Update TwinProduction/gocache to v1.2.3

* add starttls

* remove starttls from default config

Co-authored-by: Gopher Johns <gopher.johns28@gmail.com>

README.md

@@ -10,11 +10,20 @@
 Gatus is a health dashboard that gives you the ability to monitor your services using HTTP, ICMP, TCP, and even DNS
 queries as well as evaluate the result of said queries by using a list of conditions on values like the status code,
 the response time, the certificate expiration, the body and many others. The icing on top is that each of these health
-checks can be paired with alerting via Slack, PagerDuty and even Twilio.
+checks can be paired with alerting via Slack, PagerDuty, Discord and even Twilio.
 
 I personally deploy it in my Kubernetes cluster and let it monitor the status of my
 core applications: https://status.twinnation.org/
 
+<details>
+  <summary><b>Quick start</b></summary>
+
+```
+docker run -p 8080:8080 --name gatus twinproduction/gatus
+```
+For more details, see [Usage](#usage)
+</details>
+
 
 ## Table of Contents
 
@@ -47,6 +56,7 @@ core applications: https://status.twinnation.org/
   - [Monitoring a TCP service](#monitoring-a-tcp-service)
   - [Monitoring a service using ICMP](#monitoring-a-service-using-icmp)
   - [Monitoring a service using DNS queries](#monitoring-a-service-using-dns-queries)
+  - [Monitoring a service using STARTTLS](#monitoring-a-service-using-starttls)
   - [Basic authentication](#basic-authentication)
   - [disable-monitoring-lock](#disable-monitoring-lock)
   - [Reloading configuration on the fly](#reloading-configuration-on-the-fly)
@@ -77,6 +87,8 @@ fixing the issue before they even know about it.
 
 ## Features
 
+![Gatus dark mode](.github/assets/dark-mode.png)
+
 The main features of Gatus are:
 - **Highly flexible health check conditions**: While checking the response status may be enough for some use cases, Gatus goes much further and allows you to add conditions on the response time, the response body and even the IP address.
 - **Ability to use Gatus for user acceptance tests**: Thanks to the point above, you can leverage this application to create automated user acceptance tests.
@@ -85,7 +97,6 @@ The main features of Gatus are:
 - **Metrics**
 - **Low resource consumption**: As with most Go applications, the resource footprint that this application requires is negligibly small.
 - **GitHub uptime badges**: ![Uptime 1h](https://status.twinnation.org/api/v1/badges/uptime/1h/core_twinnation-external.svg) ![Uptime 24h](https://status.twinnation.org/api/v1/badges/uptime/24h/core_twinnation-external.svg) ![Uptime 7d](https://status.twinnation.org/api/v1/badges/uptime/7d/core_twinnation-external.svg)
-- **Service auto discovery in Kubernetes** (ALPHA)
 
 
 ## Usage
@@ -119,6 +130,8 @@ This example would look like this:
 
 Note that you can also use environment variables in the configuration file (e.g. `$DOMAIN`, `${DOMAIN}`)
 
+If you want to test it locally, see [Docker](#docker).
+
 
 ## Configuration
 
@@ -629,8 +642,13 @@ See [example/kubernetes-with-auto-discovery](example/kubernetes-with-auto-discov
 
 ## Docker
 
+To run Gatus locally with Docker:
+```
+docker run -p 8080:8080 --name gatus twinproduction/gatus
+```
+
 Other than using one of the examples provided in the `examples` folder, you can also try it out locally by 
-creating a configuration file - we'll call it `config.yaml` for this example - and running the following 
+creating a configuration file, we'll call it `config.yaml` for this example, and running the following 
 command:
 ```
 docker run -p 8080:8080 --mount type=bind,source="$(pwd)"/config.yaml,target=/config/config.yaml --name gatus twinproduction/gatus
@@ -792,10 +810,24 @@ There are two placeholders that can be used in the conditions for services of ty
 `NOERROR`, `FORMERR`, `SERVFAIL`, `NXDOMAIN`, etc.
 
 
+### Monitoring a service using STARTTLS
+
+If you have an email server that you want to ensure there are no problems with, monitoring it through STARTTLS 
+will serve as a good initial indicator:
+```yaml
+services:
+  - name: starttls-smtp-example
+    url: "starttls://smtp.gmail.com:587"
+    interval: 30m
+    conditions:
+      - "[CONNECTED] == true"
+      - "[CERTIFICATE_EXPIRATION] > 48h"
+```
+
+
 ### Basic authentication
 
 You can require Basic authentication by leveraging the `security.basic` configuration:
-
 ```yaml
 security:
   basic:

client/client.go

@@ -2,10 +2,14 @@ package client
 
 import (
 	"crypto/tls"
+	"crypto/x509"
+	"errors"
 	"net"
 	"net/http"
+	"net/smtp"
 	"os"
 	"strconv"
+	"strings"
 	"time"
 
 	"github.com/go-ping/ping"
@@ -74,6 +78,31 @@ func CanCreateTCPConnection(address string) bool {
 	return true
 }
 
+// CanPerformStartTLS checks whether a connection can be established to an address using the STARTTLS protocol
+func CanPerformStartTLS(address string, insecure bool) (connected bool, certificate *x509.Certificate, err error) {
+	hostAndPort := strings.Split(address, ":")
+	if len(hostAndPort) != 2 {
+		return false, nil, errors.New("invalid address for starttls, format must be host:port")
+	}
+	smtpClient, err := smtp.Dial(address)
+	if err != nil {
+		return
+	}
+	err = smtpClient.StartTLS(&tls.Config{
+		InsecureSkipVerify: insecure,
+		ServerName:         hostAndPort[0],
+	})
+	if err != nil {
+		return
+	}
+	if state, ok := smtpClient.TLSConnectionState(); ok {
+		certificate = state.PeerCertificates[0]
+	} else {
+		return false, nil, errors.New("could not get TLS connection state")
+	}
+	return true, certificate, nil
+}
+
 // Ping checks if an address can be pinged and returns the round-trip time if the address can be pinged
 //
 // Note that this function takes at least 100ms, even if the address is 127.0.0.1

client/client_test.go

@@ -49,3 +49,53 @@ func TestPing(t *testing.T) {
 		}
 	}
 }
+
+func TestCanPerformStartTLS(t *testing.T) {
+	type args struct {
+		address  string
+		insecure bool
+	}
+	tests := []struct {
+		name          string
+		args          args
+		wantConnected bool
+		wantErr       bool
+	}{
+		{
+			name: "invalid address",
+			args: args{
+				address: "test",
+			},
+			wantConnected: false,
+			wantErr:       true,
+		},
+		{
+			name: "error dial",
+			args: args{
+				address: "test:1234",
+			},
+			wantConnected: false,
+			wantErr:       true,
+		},
+		{
+			name: "valid starttls",
+			args: args{
+				address: "smtp.gmail.com:587",
+			},
+			wantConnected: true,
+			wantErr:       false,
+		},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			connected, _, err := CanPerformStartTLS(tt.args.address, tt.args.insecure)
+			if (err != nil) != tt.wantErr {
+				t.Errorf("CanPerformStartTLS() err=%v, wantErr=%v", err, tt.wantErr)
+				return
+			}
+			if connected != tt.wantConnected {
+				t.Errorf("CanPerformStartTLS() connected=%v, wantConnected=%v", connected, tt.wantConnected)
+			}
+		})
+	}
+}

core/condition.go

@@ -126,7 +126,7 @@ func (c Condition) evaluate(result *Result) bool {
 			conditionToDisplay = prettifyNumericalParameters(parameters, resolvedParameters, "<")
 		}
 	} else {
-		result.Errors = append(result.Errors, fmt.Sprintf("invalid condition '%s' has been provided", condition))
+		result.AddError(fmt.Sprintf("invalid condition '%s' has been provided", condition))
 		return false
 	}
 	if !success {
@@ -242,7 +242,7 @@ func sanitizeAndResolve(elements []string, result *Result) ([]string, []string)
 				} else {
 					if err != nil {
 						if err.Error() != "unexpected end of JSON input" {
-							result.Errors = append(result.Errors, err.Error())
+							result.AddError(err.Error())
 						}
 						if checkingForLength {
 							element = LengthFunctionPrefix + element + FunctionSuffix + " " + InvalidConditionElementSuffix

core/condition_bench_test.go

@@ -38,6 +38,15 @@ func BenchmarkCondition_evaluateWithBodyStringFailure(b *testing.B) {
 	b.ReportAllocs()
 }
 
+func BenchmarkCondition_evaluateWithBodyStringFailureInvalidPath(b *testing.B) {
+	condition := Condition("[BODY].user.name == bob.doe")
+	for n := 0; n < b.N; n++ {
+		result := &Result{body: []byte("{\"name\": \"bob.doe\"}")}
+		condition.evaluate(result)
+	}
+	b.ReportAllocs()
+}
+
 func BenchmarkCondition_evaluateWithBodyStringLen(b *testing.B) {
 	condition := Condition("len([BODY].name) == 8")
 	for n := 0; n < b.N; n++ {

core/dns.go

@@ -52,7 +52,7 @@ func (d *DNS) query(url string, result *Result) {
 	m.SetQuestion(d.QueryName, queryType)
 	r, _, err := c.Exchange(m, url)
 	if err != nil {
-		result.Errors = append(result.Errors, err.Error())
+		result.AddError(err.Error())
 		return
 	}
 	result.Connected = true

core/result.go

@@ -25,7 +25,7 @@ type Result struct {
 	Duration time.Duration `json:"duration"`
 
 	// Errors encountered during the evaluation of the service's health
-	Errors []string `json:"errors"`
+	Errors []string `json:"errors"` // XXX: find a way to filter out duplicate errors
 
 	// ConditionResults results of the service's conditions
 	ConditionResults []*ConditionResult `json:"conditionResults"`
@@ -46,3 +46,15 @@ type Result struct {
 	// and sets it to nil after the evaluation has been completed.
 	body []byte
 }
+
+// AddError adds an error to the result's list of errors.
+// It also ensures that there are no duplicates.
+func (r *Result) AddError(error string) {
+	for _, resultError := range r.Errors {
+		if resultError == error {
+			// If the error already exists, don't add it
+			return
+		}
+	}
+	r.Errors = append(r.Errors, error)
+}

core/result_test.go

@@ -0,0 +1,21 @@
+package core
+
+import (
+	"testing"
+)
+
+func TestResult_AddError(t *testing.T) {
+	result := &Result{}
+	result.AddError("potato")
+	if len(result.Errors) != 1 {
+		t.Error("should've had 1 error")
+	}
+	result.AddError("potato")
+	if len(result.Errors) != 1 {
+		t.Error("should've still had 1 error, because a duplicate error was added")
+	}
+	result.AddError("tomato")
+	if len(result.Errors) != 2 {
+		t.Error("should've had 2 error")
+	}
+}

core/service.go

@@ -2,6 +2,7 @@ package core
 
 import (
 	"bytes"
+	"crypto/x509"
 	"encoding/json"
 	"errors"
 	"io/ioutil"
@@ -155,35 +156,20 @@ func (service *Service) EvaluateHealth() *Result {
 	return result
 }
 
-// GetAlertsTriggered returns a slice of alerts that have been triggered
-func (service *Service) GetAlertsTriggered() []alert.Alert {
-	var alerts []alert.Alert
-	if service.NumberOfFailuresInARow == 0 {
-		return alerts
-	}
-	for _, alert := range service.Alerts {
-		if alert.IsEnabled() && alert.FailureThreshold == service.NumberOfFailuresInARow {
-			alerts = append(alerts, *alert)
-			continue
-		}
-	}
-	return alerts
-}
-
 func (service *Service) getIP(result *Result) {
 	if service.DNS != nil {
 		result.Hostname = strings.TrimSuffix(service.URL, ":53")
 	} else {
 		urlObject, err := url.Parse(service.URL)
 		if err != nil {
-			result.Errors = append(result.Errors, err.Error())
+			result.AddError(err.Error())
 			return
 		}
 		result.Hostname = urlObject.Hostname()
 	}
 	ips, err := net.LookupIP(result.Hostname)
 	if err != nil {
-		result.Errors = append(result.Errors, err.Error())
+		result.AddError(err.Error())
 		return
 	}
 	result.IP = ips[0].String()
@@ -193,10 +179,12 @@ func (service *Service) call(result *Result) {
 	var request *http.Request
 	var response *http.Response
 	var err error
+	var certificate *x509.Certificate
 	isServiceDNS := service.DNS != nil
 	isServiceTCP := strings.HasPrefix(service.URL, "tcp://")
 	isServiceICMP := strings.HasPrefix(service.URL, "icmp://")
-	isServiceHTTP := !isServiceDNS && !isServiceTCP && !isServiceICMP
+	isServiceStartTLS := strings.HasPrefix(service.URL, "starttls://")
+	isServiceHTTP := !isServiceDNS && !isServiceTCP && !isServiceICMP && !isServiceStartTLS
 	if isServiceHTTP {
 		request = service.buildHTTPRequest()
 	}
@@ -204,6 +192,14 @@ func (service *Service) call(result *Result) {
 	if isServiceDNS {
 		service.DNS.query(service.URL, result)
 		result.Duration = time.Since(startTime)
+	} else if isServiceStartTLS {
+		result.Connected, certificate, err = client.CanPerformStartTLS(strings.TrimPrefix(service.URL, "starttls://"), service.Insecure)
+		if err != nil {
+			result.AddError(err.Error())
+			return
+		}
+		result.Duration = time.Since(startTime)
+		result.CertificateExpiration = time.Until(certificate.NotAfter)
 	} else if isServiceTCP {
 		result.Connected = client.CanCreateTCPConnection(strings.TrimPrefix(service.URL, "tcp://"))
 		result.Duration = time.Since(startTime)
@@ -213,12 +209,12 @@ func (service *Service) call(result *Result) {
 		response, err = client.GetHTTPClient(service.Insecure).Do(request)
 		result.Duration = time.Since(startTime)
 		if err != nil {
-			result.Errors = append(result.Errors, err.Error())
+			result.AddError(err.Error())
 			return
 		}
 		defer response.Body.Close()
 		if response.TLS != nil && len(response.TLS.PeerCertificates) > 0 {
-			certificate := response.TLS.PeerCertificates[0]
+			certificate = response.TLS.PeerCertificates[0]
 			result.CertificateExpiration = time.Until(certificate.NotAfter)
 		}
 		result.HTTPStatus = response.StatusCode
@@ -227,7 +223,7 @@ func (service *Service) call(result *Result) {
 		if service.needsToReadBody() {
 			result.body, err = ioutil.ReadAll(response.Body)
 			if err != nil {
-				result.Errors = append(result.Errors, err.Error())
+				result.AddError(err.Error())
 			}
 		}
 	}

core/service_test.go

@@ -102,31 +102,6 @@ func TestService_ValidateAndSetDefaultsWithDNS(t *testing.T) {
 	}
 }
 
-func TestService_GetAlertsTriggered(t *testing.T) {
-	condition := Condition("[STATUS] == 200")
-	enabled := true
-	service := Service{
-		Name:       "twinnation-health",
-		URL:        "https://twinnation.org/health",
-		Conditions: []*Condition{&condition},
-		Alerts:     []*alert.Alert{{Type: alert.TypePagerDuty, Enabled: &enabled}},
-	}
-	service.ValidateAndSetDefaults()
-	if service.NumberOfFailuresInARow != 0 {
-		t.Error("Service.NumberOfFailuresInARow should start with 0")
-	}
-	if service.NumberOfSuccessesInARow != 0 {
-		t.Error("Service.NumberOfSuccessesInARow should start with 0")
-	}
-	if len(service.GetAlertsTriggered()) > 0 {
-		t.Error("No alerts should've been triggered, because service.NumberOfFailuresInARow is 0, which is below the failure threshold")
-	}
-	service.NumberOfFailuresInARow = service.Alerts[0].FailureThreshold
-	if len(service.GetAlertsTriggered()) != 1 {
-		t.Error("Alert should've been triggered")
-	}
-}
-
 func TestService_buildHTTPRequest(t *testing.T) {
 	condition := Condition("[STATUS] == 200")
 	service := Service{

example/docker-compose/docker-compose.yml

@@ -1,8 +1,8 @@
 version: "3.8"
 services:
-    gatus:
-        image: twinproduction/gatus:latest
-        ports:
-          - 8080:8080
-        volumes:
-          - ./config.yaml:/config/config.yaml
+  gatus:
+    image: twinproduction/gatus:latest
+    ports:
+      - 8080:8080
+    volumes:
+      - ./config.yaml:/config/config.yaml

go.mod

@@ -4,7 +4,7 @@ go 1.16
 
 require (
 	cloud.google.com/go v0.74.0 // indirect
-	github.com/TwinProduction/gocache v1.2.1
+	github.com/TwinProduction/gocache v1.2.3
 	github.com/TwinProduction/health v1.0.0
 	github.com/go-ping/ping v0.0.0-20201115131931-3300c582a663
 	github.com/google/gofuzz v1.2.0 // indirect

go.sum

@@ -49,8 +49,8 @@ github.com/PuerkitoBio/purell v1.0.0/go.mod h1:c11w/QuzBsJSee3cPx9rAFu61PvFxuPbt
 github.com/PuerkitoBio/urlesc v0.0.0-20160726150825-5bd2802263f2/go.mod h1:uGdkoq3SwY9Y+13GIhn11/XLaGBb4BfwItxLd5jeuXE=
 github.com/Shopify/sarama v1.19.0/go.mod h1:FVkBWblsNy7DGZRfXLU0O9RCGt5g3g3yEuWXgklEdEo=
 github.com/Shopify/toxiproxy v2.1.4+incompatible/go.mod h1:OXgGpZ6Cli1/URJOF1DMxUHB2q5Ap20/P/eIdh4G0pI=
-github.com/TwinProduction/gocache v1.2.1 h1:NAdMwO9SQEZFmX69YWx6fzhwb6fHakkLri0451c+V1w=
-github.com/TwinProduction/gocache v1.2.1/go.mod h1:6zkBoLjrFLkIISwkZTgLy67qliCGSon1xpORM4Ri5HM=
+github.com/TwinProduction/gocache v1.2.3 h1:4wFNih4CemUX+A99Gk/EsaU0SXSNZV42Ve77v7/7ToY=
+github.com/TwinProduction/gocache v1.2.3/go.mod h1:Yj2daITit8TTBgiOpc26XCDSbg9xcFskUilHj9u3Mh8=
 github.com/TwinProduction/health v1.0.0 h1:TVyYTAORQQZ8LaptX8jCHZRCGCAO6e+oJx19BUIzQYY=
 github.com/TwinProduction/health v1.0.0/go.mod h1:ys4mYKUeEfYrWmkm60xLtPjTuLIEDQNBZaTZvenLG1c=
 github.com/VividCortex/gohistogram v1.0.0/go.mod h1:Pf5mBqqDxYaXu3hDrrU+w6nw50o/4+TcAqDqk/vUH7g=

jsonpath/jsonpath.go

@@ -25,6 +25,9 @@ func walk(path string, object interface{}) (string, int, error) {
 	case map[string]interface{}:
 		return walk(strings.Replace(path, fmt.Sprintf("%s.", currentKey), "", 1), value)
 	case string:
+		if len(keys) > 1 {
+			return "", 0, fmt.Errorf("couldn't walk through '%s', because '%s' was a string instead of an object", keys[1], currentKey)
+		}
 		return value, len(value), nil
 	case []interface{}:
 		return fmt.Sprintf("%v", value), len(value), nil

jsonpath/jsonpath_test.go

@@ -1,180 +1,148 @@
 package jsonpath
 
-import "testing"
+import (
+	"testing"
+)
 
 func TestEval(t *testing.T) {
-	path := "simple"
-	data := `{"simple": "value"}`
-
-	expectedOutput := "value"
-
-	output, outputLength, err := Eval(path, []byte(data))
-	if err != nil {
-		t.Error("Didn't expect any error, but got", err)
+	type Scenario struct {
+		Name                 string
+		Path                 string
+		Data                 string
+		ExpectedOutput       string
+		ExpectedOutputLength int
+		ExpectedError        bool
 	}
-	if outputLength != len(expectedOutput) {
-		t.Errorf("Expected output length to be %v, but was %v", len(expectedOutput), outputLength)
+	scenarios := []Scenario{
+		{
+			Name:                 "simple",
+			Path:                 "key",
+			Data:                 `{"key": "value"}`,
+			ExpectedOutput:       "value",
+			ExpectedOutputLength: 5,
+			ExpectedError:        false,
+		},
+		{
+			Name:                 "simple-with-invalid-data",
+			Path:                 "key",
+			Data:                 "invalid data",
+			ExpectedOutput:       "",
+			ExpectedOutputLength: 0,
+			ExpectedError:        true,
+		},
+		{
+			Name:                 "invalid-path",
+			Path:                 "key",
+			Data:                 `{}`,
+			ExpectedOutput:       "",
+			ExpectedOutputLength: 0,
+			ExpectedError:        true,
+		},
+		{
+			Name:                 "long-simple-walk",
+			Path:                 "long.simple.walk",
+			Data:                 `{"long": {"simple": {"walk": "value"}}}`,
+			ExpectedOutput:       "value",
+			ExpectedOutputLength: 5,
+			ExpectedError:        false,
+		},
+		{
+			Name:                 "array-of-maps",
+			Path:                 "ids[1].id",
+			Data:                 `{"ids": [{"id": 1}, {"id": 2}]}`,
+			ExpectedOutput:       "2",
+			ExpectedOutputLength: 1,
+			ExpectedError:        false,
+		},
+		{
+			Name:                 "array-of-values",
+			Path:                 "ids[0]",
+			Data:                 `{"ids": [1, 2]}`,
+			ExpectedOutput:       "1",
+			ExpectedOutputLength: 1,
+			ExpectedError:        false,
+		},
+		{
+			Name:                 "array-of-values-and-invalid-index",
+			Path:                 "ids[wat]",
+			Data:                 `{"ids": [1, 2]}`,
+			ExpectedOutput:       "",
+			ExpectedOutputLength: 0,
+			ExpectedError:        true,
+		},
+		{
+			Name:                 "array-of-values-at-root",
+			Path:                 "[1]",
+			Data:                 `[1, 2]`,
+			ExpectedOutput:       "2",
+			ExpectedOutputLength: 1,
+			ExpectedError:        false,
+		},
+		{
+			Name:                 "array-of-maps-at-root",
+			Path:                 "[0].id",
+			Data:                 `[{"id": 1}, {"id": 2}]`,
+			ExpectedOutput:       "1",
+			ExpectedOutputLength: 1,
+			ExpectedError:        false,
+		},
+		{
+			Name:                 "array-of-maps-at-root-and-invalid-index",
+			Path:                 "[5].id",
+			Data:                 `[{"id": 1}, {"id": 2}]`,
+			ExpectedOutput:       "",
+			ExpectedOutputLength: 0,
+			ExpectedError:        true,
+		},
+		{
+			Name:                 "long-walk-and-array",
+			Path:                 "data.ids[0].id",
+			Data:                 `{"data": {"ids": [{"id": 1}, {"id": 2}, {"id": 3}]}}`,
+			ExpectedOutput:       "1",
+			ExpectedOutputLength: 1,
+			ExpectedError:        false,
+		},
+		{
+			Name:                 "nested-array",
+			Path:                 "[3][2]",
+			Data:                 `[[1, 2], [3, 4], [], [5, 6, 7]]`,
+			ExpectedOutput:       "7",
+			ExpectedOutputLength: 1,
+			ExpectedError:        false,
+		},
+		{
+			Name:                 "map-of-nested-arrays",
+			Path:                 "data[1][1]",
+			Data:                 `{"data": [["a", "b", "c"], ["d", "eeeee", "f"]]}`,
+			ExpectedOutput:       "eeeee",
+			ExpectedOutputLength: 5,
+			ExpectedError:        false,
+		},
+		{
+			Name:                 "partially-invalid-path-issue122",
+			Path:                 "data.name.invalid",
+			Data:                 `{"data": {"name": "john"}}`,
+			ExpectedOutput:       "",
+			ExpectedOutputLength: 0,
+			ExpectedError:        true,
+		},
 	}
-	if output != expectedOutput {
-		t.Errorf("Expected output to be %v, but was %v", expectedOutput, output)
-	}
-}
-
-func TestEvalWithInvalidData(t *testing.T) {
-	path := "simple"
-	data := `invalid data`
-	_, _, err := Eval(path, []byte(data))
-	if err == nil {
-		t.Error("expected an error")
-	}
-}
-
-func TestEvalWithInvalidPath(t *testing.T) {
-	path := "errors"
-	data := `{}`
-	_, _, err := Eval(path, []byte(data))
-	if err == nil {
-		t.Error("Expected error, but got", err)
-	}
-}
-
-func TestEvalWithLongSimpleWalk(t *testing.T) {
-	path := "long.simple.walk"
-	data := `{"long": {"simple": {"walk": "value"}}}`
-
-	expectedOutput := "value"
-
-	output, _, err := Eval(path, []byte(data))
-	if err != nil {
-		t.Error("Didn't expect any error, but got", err)
-	}
-	if output != expectedOutput {
-		t.Errorf("Expected output to be %v, but was %v", expectedOutput, output)
-	}
-}
-
-func TestEvalWithArrayOfMaps(t *testing.T) {
-	path := "ids[1].id"
-	data := `{"ids": [{"id": 1}, {"id": 2}]}`
-
-	expectedOutput := "2"
-
-	output, _, err := Eval(path, []byte(data))
-	if err != nil {
-		t.Error("Didn't expect any error, but got", err)
-	}
-
-	if output != expectedOutput {
-		t.Errorf("Expected output to be %v, but was %v", expectedOutput, output)
-	}
-}
-
-func TestEvalWithArrayOfValues(t *testing.T) {
-	path := "ids[0]"
-	data := `{"ids": [1, 2]}`
-
-	expectedOutput := "1"
-
-	output, _, err := Eval(path, []byte(data))
-	if err != nil {
-		t.Error("Didn't expect any error, but got", err)
-	}
-	if output != expectedOutput {
-		t.Errorf("Expected output to be %v, but was %v", expectedOutput, output)
-	}
-}
-
-func TestEvalWithArrayOfValuesAndInvalidIndex(t *testing.T) {
-	path := "ids[wat]"
-	data := `{"ids": [1, 2]}`
-
-	_, _, err := Eval(path, []byte(data))
-	if err == nil {
-		t.Error("Expected an error")
-	}
-}
-
-func TestEvalWithRootArrayOfValues(t *testing.T) {
-	path := "[1]"
-	data := `[1, 2]`
-
-	expectedOutput := "2"
-
-	output, _, err := Eval(path, []byte(data))
-	if err != nil {
-		t.Error("Didn't expect any error, but got", err)
-	}
-	if output != expectedOutput {
-		t.Errorf("Expected output to be %v, but was %v", expectedOutput, output)
-	}
-}
-
-func TestEvalWithRootArrayOfMaps(t *testing.T) {
-	path := "[0].id"
-	data := `[{"id": 1}, {"id": 2}]`
-
-	expectedOutput := "1"
-
-	output, _, err := Eval(path, []byte(data))
-	if err != nil {
-		t.Error("Didn't expect any error, but got", err)
-	}
-	if output != expectedOutput {
-		t.Errorf("Expected output to be %v, but was %v", expectedOutput, output)
-	}
-}
-
-func TestEvalWithRootArrayOfMapsUsingInvalidArrayIndex(t *testing.T) {
-	path := "[5].id"
-	data := `[{"id": 1}, {"id": 2}]`
-
-	_, _, err := Eval(path, []byte(data))
-	if err == nil {
-		t.Error("Should've returned an error, but didn't")
-	}
-}
-
-func TestEvalWithLongWalkAndArray(t *testing.T) {
-	path := "data.ids[0].id"
-	data := `{"data": {"ids": [{"id": 1}, {"id": 2}, {"id": 3}]}}`
-
-	expectedOutput := "1"
-
-	output, _, err := Eval(path, []byte(data))
-	if err != nil {
-		t.Error("Didn't expect any error, but got", err)
-	}
-	if output != expectedOutput {
-		t.Errorf("Expected output to be %v, but was %v", expectedOutput, output)
-	}
-}
-
-func TestEvalWithNestedArray(t *testing.T) {
-	path := "[3][2]"
-	data := `[[1, 2], [3, 4], [], [5, 6, 7]]`
-
-	expectedOutput := "7"
-
-	output, _, err := Eval(path, []byte(data))
-	if err != nil {
-		t.Error("Didn't expect any error, but got", err)
-	}
-	if output != expectedOutput {
-		t.Errorf("Expected output to be %v, but was %v", expectedOutput, output)
-	}
-}
-
-func TestEvalWithMapOfNestedArray(t *testing.T) {
-	path := "data[1][1]"
-	data := `{"data": [["a", "b", "c"], ["d", "e", "f"]]}`
-
-	expectedOutput := "e"
-
-	output, _, err := Eval(path, []byte(data))
-	if err != nil {
-		t.Error("Didn't expect any error, but got", err)
-	}
-	if output != expectedOutput {
-		t.Errorf("Expected output to be %v, but was %v", expectedOutput, output)
+	for _, scenario := range scenarios {
+		t.Run(scenario.Name, func(t *testing.T) {
+			output, outputLength, err := Eval(scenario.Path, []byte(scenario.Data))
+			if (err != nil) != scenario.ExpectedError {
+				if scenario.ExpectedError {
+					t.Errorf("Expected error, got '%v'", err)
+				} else {
+					t.Errorf("Expected no error, got '%v'", err)
+				}
+			}
+			if outputLength != scenario.ExpectedOutputLength {
+				t.Errorf("Expected output length to be %v, but was %v", scenario.ExpectedOutputLength, outputLength)
+			}
+			if output != scenario.ExpectedOutput {
+				t.Errorf("Expected output to be %v, but was %v", scenario.ExpectedOutput, output)
+			}
+		})
 	}
 }

vendor/github.com/TwinProduction/gocache/Dockerfile

@@ -2,7 +2,7 @@
 FROM golang:alpine as builder
 WORKDIR /app
 ADD . ./
-RUN CGO_ENABLED=0 GOOS=linux go build -mod vendor -a -installsuffix cgo -o bin/gocache-server ./gocacheserver/main
+RUN CGO_ENABLED=0 GOOS=linux go build -mod vendor -a -installsuffix cgo -o bin/gocache-server cmd/server/main.go
 RUN apk --update add --no-cache ca-certificates
 
 FROM scratch

vendor/github.com/TwinProduction/gocache/LICENSE.md

@@ -1,6 +1,6 @@
 MIT License
 
-Copyright (c) 2020 TwinProduction
+Copyright (c) 2021 TwinProduction
 
 Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:
 

vendor/github.com/TwinProduction/gocache/Makefile

@@ -12,7 +12,7 @@ docker-run-max-memory-usage:
 	docker run -p 6666:6379 -e AUTOSAVE=true -e MAX_CACHE_SIZE=0 -e MAX_MEMORY_USAGE=524288000 --name gocache-server -d gocache-server
 
 run:
-	PORT=6666 go run gocacheserver/main/server.go
+	PORT=6666 go run cmd/server/main.go
 
 start-redis:
 	docker run -p 6379:6379 --name redis -d redis

vendor/github.com/TwinProduction/gocache/README.md

@@ -5,6 +5,7 @@
 [![codecov](https://codecov.io/gh/TwinProduction/gocache/branch/master/graph/badge.svg)](https://codecov.io/gh/TwinProduction/gocache)
 [![Go version](https://img.shields.io/github/go-mod/go-version/TwinProduction/gocache.svg)](https://github.com/TwinProduction/gocache)
 [![Go Reference](https://pkg.go.dev/badge/github.com/TwinProduction/gocache.svg)](https://pkg.go.dev/github.com/TwinProduction/gocache)
+[![Follow TwinProduction](https://img.shields.io/github/followers/TwinProduction?label=Follow&style=social)](https://github.com/TwinProduction)
 
 gocache is an easy-to-use, high-performance, lightweight and thread-safe (goroutine-safe) in-memory key-value cache 
 with support for LRU and FIFO eviction policies as well as expiration, bulk operations and even persistence to file.
@@ -33,6 +34,8 @@ with support for LRU and FIFO eviction policies as well as expiration, bulk oper
   - [Summary](#summary)
   - [Results](#results)
 - [FAQ](#faq)
+  - [How can I persist the data on application termination?](#how-can-i-persist-the-data-on-application-termination)
+  - [How can I automatically save the cache to a file every 5 minutes?](#how-can-i-automatically-save-the-cache-to-a-file-every-5-minutes)
   - [Why does the memory usage not go down?](#why-does-the-memory-usage-not-go-down)
 
 
@@ -58,6 +61,9 @@ It may also serve as a good reference to use in order to implement gocache in yo
 go get -u github.com/TwinProduction/gocache
 ```
 
+If you're interested in using gocache as a server rather than an embedded library, see [Server](#server)
+
+
 ### Initializing the cache
 ```go
 cache := gocache.NewCache().WithMaxSize(1000).WithEvictionPolicy(gocache.LeastRecentlyUsed)
@@ -125,52 +131,52 @@ You can also delete multiple entries by using `cache.DeleteAll([]string{"key1",
 package main
 
 import (
-	"fmt"
-	"time"
+    "fmt"
+    "time"
 
     "github.com/TwinProduction/gocache"
 )
 
 func main() {
-	cache := gocache.NewCache().WithEvictionPolicy(gocache.LeastRecentlyUsed).WithMaxSize(10000)
-	cache.StartJanitor() // Passively manages expired entries
+    cache := gocache.NewCache().WithEvictionPolicy(gocache.LeastRecentlyUsed).WithMaxSize(10000)
+    cache.StartJanitor() // Passively manages expired entries
 
-	cache.Set("key", "value")
-	cache.SetWithTTL("key-with-ttl", "value", 60*time.Minute)
-	cache.SetAll(map[string]interface{}{"k1": "v1", "k2": "v2", "k3": "v3"})
+    cache.Set("key", "value")
+    cache.SetWithTTL("key-with-ttl", "value", 60*time.Minute)
+    cache.SetAll(map[string]interface{}{"k1": "v1", "k2": "v2", "k3": "v3"})
 
-	value, exists := cache.Get("key")
-	fmt.Printf("[Get] key=key; value=%s; exists=%v\n", value, exists)
-	for key, value := range cache.GetByKeys([]string{"k1", "k2", "k3"}) {
-		fmt.Printf("[GetByKeys] key=%s; value=%s\n", key, value)
-	}
-	for _, key := range cache.GetKeysByPattern("key*", 0) {
-		fmt.Printf("[GetKeysByPattern] key=%s\n", key)
-	}
+    value, exists := cache.Get("key")
+    fmt.Printf("[Get] key=key; value=%s; exists=%v\n", value, exists)
+    for key, value := range cache.GetByKeys([]string{"k1", "k2", "k3"}) {
+        fmt.Printf("[GetByKeys] key=%s; value=%s\n", key, value)
+    }
+    for _, key := range cache.GetKeysByPattern("key*", 0) {
+        fmt.Printf("[GetKeysByPattern] key=%s\n", key)
+    }
 
-	fmt.Println("Cache size before persisting cache to file:", cache.Count())
-	err := cache.SaveToFile("cache.bak")
-	if err != nil {
-		panic(fmt.Sprintf("failed to persist cache to file: %s", err.Error()))
-	}
+    fmt.Println("Cache size before persisting cache to file:", cache.Count())
+    err := cache.SaveToFile("cache.bak")
+    if err != nil {
+        panic(fmt.Sprintf("failed to persist cache to file: %s", err.Error()))
+    }
 
-	cache.Expire("key", time.Hour)
-	time.Sleep(500*time.Millisecond)
-	timeUntilExpiration, _ := cache.TTL("key")
-	fmt.Println("Number of minutes before 'key' expires:", int(timeUntilExpiration.Seconds()))
+    cache.Expire("key", time.Hour)
+    time.Sleep(500*time.Millisecond)
+    timeUntilExpiration, _ := cache.TTL("key")
+    fmt.Println("Number of minutes before 'key' expires:", int(timeUntilExpiration.Seconds()))
 
-	cache.Delete("key")
-	cache.DeleteAll([]string{"k1", "k2", "k3"})
+    cache.Delete("key")
+    cache.DeleteAll([]string{"k1", "k2", "k3"})
 
-	fmt.Println("Cache size before restoring cache from file:", cache.Count())
-	_, err = cache.ReadFromFile("cache.bak")
-	if err != nil {
-		panic(fmt.Sprintf("failed to restore cache from file: %s", err.Error()))
-	}
+    fmt.Println("Cache size before restoring cache from file:", cache.Count())
+    _, err = cache.ReadFromFile("cache.bak")
+    if err != nil {
+        panic(fmt.Sprintf("failed to restore cache from file: %s", err.Error()))
+    }
 
-	fmt.Println("Cache size after restoring cache from file:", cache.Count())
-	cache.Clear()
-	fmt.Println("Cache size after clearing the cache:", cache.Count())
+    fmt.Println("Cache size after restoring cache from file:", cache.Count())
+    cache.Clear()
+    fmt.Println("Cache size after clearing the cache:", cache.Count())
 }
 ```
 
@@ -215,8 +221,8 @@ While you can cache structs in memory out of the box, persisting structs to a fi
 
 ```go
 type YourCustomStruct struct {
-	A string
-	B int
+    A string
+    B int
 }
 
 // ...
@@ -251,6 +257,13 @@ every key that cannot be parsed are not populated into the cache by `ReadFromFil
 In other words, if you're falling back to a database or something similar when the cache doesn't have the key requested,
 you'll be fine.
 
+Note that if you need to modify the type of a variable in a struct, you should change the name of that variable as well.
+For instance, if the struct has a `CreatedAt` variable with the type `time.Time` and that variable type is later
+modified to `uint64`, decoding the struct would fail, however, if you rename the variable to `CreatedAtUnixTimeInMs`,
+there won't be any decoding issues other than the loss of data for that field. You could also obviously handle the 
+migration gracefully by keeping both variables, populating the `CreatedAtUnixTimeInMs` variable with the `CreatedAt`
+value and then removing the `CreatedAt` field.
+
 
 ## Eviction
 
@@ -303,31 +316,37 @@ If you do not start the janitor, there will be no passive deletion of expired ke
 
 
 ## Server
-For the sake of convenience, a ready-to-go cache server is available 
-through the `gocacheserver` package. 
-
-The reason why the server is in a different package is because `gocache` limit its external dependencies to the strict 
-minimum (e.g. boltdb for persistence), however, rather than re-inventing the wheel, the server implementation uses
-redcon, which is a very good Redis server framework for Go.
-
-That way, those who desire to use gocache without the server will not add any extra dependencies
-as long as they don't import the `gocacheserver` package. 
+For the sake of convenience, a ready-to-go cache server is available through the `server` package.
 
+#### As an application
 ```go
 package main
 
 import (
-	"github.com/TwinProduction/gocache"
-	"github.com/TwinProduction/gocache/gocacheserver"
+    "github.com/TwinProduction/gocache"
+    gocacheserver "github.com/TwinProduction/gocache/server"
 )
 
 func main() {
-	cache := gocache.NewCache().WithEvictionPolicy(gocache.LeastRecentlyUsed).WithMaxSize(100000)
-	server := gocacheserver.NewServer(cache).WithPort(6379)
-	server.Start()
+    cache := gocache.NewCache().WithEvictionPolicy(gocache.LeastRecentlyUsed).WithMaxSize(100000)
+    server := gocacheserver.NewServer(cache).WithPort(6379)
+    // This is a blocking function, therefore, you are expected to run this on a goroutine
+    server.Start()
 }
 ```
 
+The reason why the server is in a different package is because `gocache` limit its external dependencies to the strict
+minimum (e.g. boltdb for persistence), however, rather than re-inventing the wheel, the server implementation uses
+redcon, which is a very good Redis server framework for Go.
+
+That way, those who desire to use gocache without the server will not add any extra dependencies
+as long as they don't import the `server` package.
+
+If you'd like to run it through the CLI:
+```
+go run cmd/server/main.go
+```
+
 Any Redis client should be able to interact with the server, though only the following instructions are supported:
 - [X] GET
 - [X] SET
@@ -350,14 +369,12 @@ Any Redis client should be able to interact with the server, though only the fol
 ## Running the server with Docker
 [![Docker pulls](https://img.shields.io/docker/pulls/twinproduction/gocache-server.svg)](https://cloud.docker.com/repository/docker/twinproduction/gocache-server)
 
-To build it locally, refer to the Makefile's `docker-build` and `docker-run` steps.
-
-Note that the server version of gocache is still under development.
-
 ```
 docker run --name gocache-server -p 6379:6379 twinproduction/gocache-server
 ```
 
+To build it locally, refer to the Makefile's `docker-build` and `docker-run` steps.
+
 
 ## Performance
 
@@ -448,9 +465,96 @@ WithForceNilInterfaceOnNilPointerWithConcurrency/false-8
 
 ## FAQ
 
+### How can I persist the data on application termination?
+
+Because this library doesn't persist immediately after every write operations, persistence is instead expected to be
+done on a schedule, like for instance, every 10 minutes.
+
+While this prevents you from losing all of your data, you may still lose some data if the application stopped 9 minutes
+after the previous "auto save".
+
+To increase your odds of not losing any data, you can use Go's `signal` package, more specifically its `Notify` function
+which allows listening for termination signals like SIGTERM and SIGINT. Once a termination signal is caught, you can
+add the necessary logic for a graceful shutdown.
+
+In the following example, the code that would usually be present in the `main` function is moved to a different function
+named `Start` which is launched on a different goroutine so that listening for a termination signals is what blocks the
+main goroutine instead:
+
+```go
+package main
+
+import (
+    "log"
+    "os"
+    "os/signal"
+    "syscall"
+
+    "github.com/TwinProduction/gocache"
+)
+
+const CacheFile = "gocache.data"
+
+var cache = gocache.NewCache()
+
+func main() {
+    // Load persisted data from file
+    cache.ReadFromFile(CacheFile)
+    // Start everything else on another goroutine to prevent blocking the main goroutine
+    go Start()
+    // Wait for termination signal
+    sig := make(chan os.Signal, 1)
+    done := make(chan bool, 1)
+    signal.Notify(sig, os.Interrupt, syscall.SIGTERM)
+    go func() {
+        <-sig
+        log.Println("Received termination signal, attempting to gracefully shut down")
+        err := cache.SaveToFile(CacheFile)
+        if err != nil {
+            log.Println("Failed to save storage provider:", err.Error())
+        }
+        done <- true
+    }()
+    <-done
+    log.Println("Shutting down")
+}
+```
+
+Note that this won't protect you from a SIGKILL, as this signal cannot be caught.
+
+
+### How can I automatically save the cache to a file every 5 minutes?
+
+Beside using the suggestion above, automatically persisting the cache on an interval will protect your application from
+sudden terminations triggered by signals that cannot be caught, such as the force kill signal received by an application
+being OOMKilled.
+
+The simplest implementation could be something like this:
+```go
+const CacheFile = "gocache.data"
+
+func main() {
+    cache := gocache.NewCache()
+    cache.ReadFromFile(CacheFile)
+    go autoSave(10*time.Minute)
+    // ...
+}
+
+func autoSave(interval time.Duration) {
+    for {
+        err := cache.SaveToFile(CacheFile)
+        if err != nil {
+            log.Println("Failed to persist cache to file:", err.Error())
+        }
+        time.Sleep(interval)
+    }
+}
+```
+
+
 ### Why does the memory usage not go down?
 
-> **NOTE**: As of Go 1.16, this will no longer apply. See [golang/go#42330](https://github.com/golang/go/issues/42330)
+> **NOTE**: As of Go 1.16, this no longer applies. See [golang/go#42330](https://github.com/golang/go/issues/42330)
 
 By default, Go uses `MADV_FREE` if the kernel supports it to release memory, which is significantly more efficient 
 than using `MADV_DONTNEED`. Unfortunately, this means that RSS doesn't go down unless the OS actually needs the 
@@ -463,7 +567,7 @@ notice the memory usage lowering.
 [reference](https://github.com/golang/go/issues/33376#issuecomment-666455792)
 
 You can reproduce this by following the steps below:
-- Start gocacheserver
+- Start the server
 - Note the memory usage
 - Create 500k keys
 - Note the memory usage

vendor/github.com/TwinProduction/gocache/go.mod

@@ -1,6 +1,6 @@
 module github.com/TwinProduction/gocache
 
-go 1.15
+go 1.16
 
 require (
 	github.com/go-redis/redis v6.15.9+incompatible

vendor/github.com/TwinProduction/gocache/go.sum

@@ -9,11 +9,9 @@ github.com/golang/protobuf v1.4.0-rc.1.0.20200221234624-67d41d38c208/go.mod h1:x
 github.com/golang/protobuf v1.4.0-rc.2/go.mod h1:LlEzMj4AhA7rCAGe4KMBDvJI+AwstrUpVNzEA03Pprs=
 github.com/golang/protobuf v1.4.0-rc.4.0.20200313231945-b860323f09d0/go.mod h1:WU3c8KckQ9AFe+yFwt9sWVRKCVIyN9cPHBJSNnbL67w=
 github.com/golang/protobuf v1.4.0/go.mod h1:jodUvKwWbYaEsadDk5Fwe5c77LiNKVO9IDvqG2KuDX0=
-github.com/golang/protobuf v1.4.2 h1:+Z5KGCizgyZCbGh1KZqA0fcLLkwbsjIzS4aV2v7wJX0=
 github.com/golang/protobuf v1.4.2/go.mod h1:oDoupMAO8OvCJWAcko0GGGIgR6R6ocIYbsSw735rRwI=
 github.com/google/go-cmp v0.3.0/go.mod h1:8QqcDgzrUqlUb/G2PQTWiueGozuR1884gddMywk6iLU=
 github.com/google/go-cmp v0.3.1/go.mod h1:8QqcDgzrUqlUb/G2PQTWiueGozuR1884gddMywk6iLU=
-github.com/google/go-cmp v0.4.0 h1:xsAVV57WRhGj6kEIi8ReJzQlHHqcBYCElAvkovg3B/4=
 github.com/google/go-cmp v0.4.0/go.mod h1:v8dTdLbMG2kIc/vJvl+f65V22dbkXbowE6jgT/gNBxE=
 github.com/hpcloud/tail v1.0.0/go.mod h1:ab1qPbhIpdTxEkNHXyeSf5vhxWSCs/tWer42PpOxQnU=
 github.com/nxadm/tail v1.4.4 h1:DQuhQpB1tVlglWS2hLQ5OV6B5r8aGxSrPc5Qo6uTN78=
@@ -55,9 +53,7 @@ google.golang.org/protobuf v0.0.0-20200221191635-4d8936d0db64/go.mod h1:kwYJMbMJ
 google.golang.org/protobuf v0.0.0-20200228230310-ab0ca4ff8a60/go.mod h1:cfTl7dwQJ+fmap5saPgwCLgHXTUD7jkjRqWcaiX5VyM=
 google.golang.org/protobuf v1.20.1-0.20200309200217-e05f789c0967/go.mod h1:A+miEFZTKqfCUM6K7xSMQL9OKL/b6hQv+e19PK+JZNE=
 google.golang.org/protobuf v1.21.0/go.mod h1:47Nbq4nVaFHyn7ilMalzfO3qCViNmqZ2kzikPIcrTAo=
-google.golang.org/protobuf v1.23.0 h1:4MY060fB1DLGMB/7MBTLnwQUY6+F09GEiz6SsrNqyzM=
 google.golang.org/protobuf v1.23.0/go.mod h1:EGpADcykh3NcUnDUJcl1+ZksZNG86OlYog2l/sGQquU=
-gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405 h1:yhCVgyC4o1eVCa2tZl7eS0r+SDo693bJlVdllGtEeKM=
 gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
 gopkg.in/fsnotify.v1 v1.4.7/go.mod h1:Tz8NjZHkW78fSQdbUxIjBTcgA1z1m8ZHf0WmKUhAMys=
 gopkg.in/tomb.v1 v1.0.0-20141024135613-dd632973f1e7 h1:uRGJdciOHaEIrze2W8Q3AKkepLTh2hOroT7a+7czfdQ=

vendor/github.com/TwinProduction/gocache/gocache.go

@@ -239,12 +239,12 @@ func (cache *Cache) SetWithTTL(key string, value interface{}, ttl time.Duration)
 			Key:               key,
 			Value:             value,
 			RelevantTimestamp: time.Now(),
-			previous:          cache.head,
+			next:              cache.head,
 		}
 		if cache.head == nil {
 			cache.tail = entry
 		} else {
-			cache.head.next = entry
+			cache.head.previous = entry
 		}
 		cache.head = entry
 		cache.entries[key] = entry
@@ -260,7 +260,7 @@ func (cache *Cache) SetWithTTL(key string, value interface{}, ttl time.Duration)
 			return
 		}
 		if cache.maxMemoryUsage != NoMaxMemoryUsage {
-			// Substract the old entry from the cache's memoryUsage
+			// Subtract the old entry from the cache's memoryUsage
 			cache.memoryUsage -= entry.SizeInBytes()
 		}
 		// Update existing entry's value
@@ -278,8 +278,8 @@ func (cache *Cache) SetWithTTL(key string, value interface{}, ttl time.Duration)
 	} else {
 		entry.Expiration = NoExpiration
 	}
-	// If the cache doesn't have a maxSize/maxMemoryUsage, then there's no point checking if we need to evict
-	// an entry, so we'll just return now
+	// If the cache doesn't have a maxSize/maxMemoryUsage, then there's no point
+	// checking if we need to evict an entry, so we'll just return now
 	if cache.maxSize == NoMaxSize && cache.maxMemoryUsage == NoMaxMemoryUsage {
 		cache.mutex.Unlock()
 		return
@@ -519,10 +519,10 @@ func (cache *Cache) moveExistingEntryToHead(entry *Entry) {
 		cache.removeExistingEntryReferences(entry)
 	}
 	if entry != cache.head {
-		entry.previous = cache.head
-		entry.next = nil
+		entry.next = cache.head
+		entry.previous = nil
 		if cache.head != nil {
-			cache.head.next = entry
+			cache.head.previous = entry
 		}
 		cache.head = entry
 	}
@@ -536,9 +536,9 @@ func (cache *Cache) removeExistingEntryReferences(entry *Entry) {
 		cache.tail = nil
 		cache.head = nil
 	} else if cache.tail == entry {
-		cache.tail = cache.tail.next
+		cache.tail = cache.tail.previous
 	} else if cache.head == entry {
-		cache.head = cache.head.previous
+		cache.head = cache.head.next
 	}
 	if entry.previous != nil {
 		entry.previous.next = entry.next

vendor/github.com/TwinProduction/gocache/janitor.go

@@ -33,7 +33,7 @@ func (cache *Cache) StartJanitor() error {
 	}
 	cache.stopJanitor = make(chan bool)
 	go func() {
-		// rather than starting from the tail on every run, we can try to start from the last next entry
+		// rather than starting from the tail on every run, we can try to start from the last traversed entry
 		var lastTraversedNode *Entry
 		totalNumberOfExpiredKeysInPreviousRunFromTailToHead := 0
 		backOff := JanitorMinShiftBackOff
@@ -62,13 +62,14 @@ func (cache *Cache) StartJanitor() error {
 						totalNumberOfExpiredKeysInPreviousRunFromTailToHead = 0
 					}
 					for current != nil {
-						var next *Entry
+						// since we're walking from the tail to the head, we get the previous reference
+						var previous *Entry
 						steps++
 						if current.Expired() {
 							expiredEntriesFound++
-							// Because delete will remove the next reference from the entry, we need to store the
-							// next reference before we delete it
-							next = current.next
+							// Because delete will remove the previous reference from the entry, we need to store the
+							// previous reference before we delete it
+							previous = current.previous
 							cache.delete(current.Key)
 							cache.stats.ExpiredKeys++
 						}
@@ -76,11 +77,11 @@ func (cache *Cache) StartJanitor() error {
 							lastTraversedNode = nil
 							break
 						}
-						// Travel to the current node's next node only if no specific next node has been specified
-						if next != nil {
-							current = next
+						// Travel to the current node's previous node only if no specific previous node has been specified
+						if previous != nil {
+							current = previous
 						} else {
-							current = current.next
+							current = current.previous
 						}
 						lastTraversedNode = current
 						if steps == JanitorMaxIterationsPerShift || expiredEntriesFound >= JanitorShiftTarget {
@@ -131,8 +132,8 @@ func (cache *Cache) StartJanitor() error {
 func (cache *Cache) StopJanitor() {
 	if cache.stopJanitor != nil {
 		// Tell the janitor to stop, and then wait for the janitor to reply on the same channel that it's stopping
-		// This may seem a bit odd, but this allows us to avoid a data race condition in which setting cache.stopJanitor
-		// to nil
+		// This may seem a bit odd, but this allows us to avoid a data race condition when trying to set
+		// cache.stopJanitor to nil
 		cache.stopJanitor <- true
 		<-cache.stopJanitor
 		cache.stopJanitor = nil

vendor/github.com/TwinProduction/gocache/persistence.go

@@ -85,6 +85,12 @@ func (cache *Cache) ReadFromFile(path string) (int, error) {
 			if err != nil {
 				// Failed to decode the value, so we'll skip it.
 				// This is likely due to the fact that the custom struct wasn't registered using gob.Register(...)
+				//
+				// Could also be due to a breaking change in a struct's variable. For instance, if the struct has
+				// a variable with a type map[string]string and that variable is modified to map[string]int,
+				// decoding the struct would fail. This can be avoided by using a different variable name every
+				// time you must change the type of a variable within a struct.
+				//
 				// See [Persistence - Limitations](https://github.com/TwinProduction/gocache#limitations)
 				return err
 			}
@@ -114,8 +120,8 @@ func (cache *Cache) ReadFromFile(path string) (int, error) {
 			cache.tail = current
 			cache.head = current
 		} else {
-			previous.next = current
-			current.previous = previous
+			previous.previous = current
+			current.next = previous
 			cache.head = current
 		}
 		previous = entries[i]

vendor/github.com/TwinProduction/gocache/policy.go

@@ -1,5 +1,6 @@
 package gocache
 
+// EvictionPolicy is what dictates how evictions are handled
 type EvictionPolicy string
 
 var (

vendor/modules.txt

@@ -1,7 +1,7 @@
 # cloud.google.com/go v0.74.0
 ## explicit
 cloud.google.com/go/compute/metadata
-# github.com/TwinProduction/gocache v1.2.1
+# github.com/TwinProduction/gocache v1.2.3
 ## explicit
 github.com/TwinProduction/gocache
 # github.com/TwinProduction/health v1.0.0

web/app/src/components/Settings.vue

@@ -1,24 +1,20 @@
 <template>
-  <div id="settings">
-    <div class="flex">
-      <div class="flex bg-gray-200 border-gray-300 rounded border shadow dark:text-gray-200 dark:bg-gray-800 dark:border-gray-500">
-        <div class="text-xs text-gray-600 rounded-xl py-1 px-2 dark:text-gray-200">
-          &#x21bb;
-        </div>
-        <select class="text-center text-gray-500 text-xs dark:text-gray-200 dark:bg-gray-800 border-r border-l border-gray-300 dark:border-gray-500" id="refresh-rate" ref="refreshInterval" @change="handleChangeRefreshInterval">
-          <option value="10" :selected="refreshInterval === 10">10s</option>
-          <option value="30" :selected="refreshInterval === 30">30s</option>
-          <option value="60" :selected="refreshInterval === 60">1m</option>
-          <option value="120" :selected="refreshInterval === 120">2m</option>
-          <option value="300" :selected="refreshInterval === 300">5m</option>
-          <option value="600" :selected="refreshInterval === 600">10m</option>
-        </select>
-        <button @click="toggleDarkMode" class="text-xs p-1">
-          <slot v-if="darkMode">☀</slot>
-          <slot v-else>🌙</slot>
-        </button>
-      </div>
+  <div id="settings" class="flex bg-gray-200 border-gray-300 rounded border shadow dark:text-gray-200 dark:bg-gray-800 dark:border-gray-500">
+    <div class="text-xs text-gray-600 rounded-xl py-1 px-2 dark:text-gray-200">
+      &#x21bb;
     </div>
+    <select class="text-center text-gray-500 text-xs dark:text-gray-200 dark:bg-gray-800 border-r border-l border-gray-300 dark:border-gray-500" id="refresh-rate" ref="refreshInterval" @change="handleChangeRefreshInterval">
+      <option value="10" :selected="refreshInterval === 10">10s</option>
+      <option value="30" :selected="refreshInterval === 30">30s</option>
+      <option value="60" :selected="refreshInterval === 60">1m</option>
+      <option value="120" :selected="refreshInterval === 120">2m</option>
+      <option value="300" :selected="refreshInterval === 300">5m</option>
+      <option value="600" :selected="refreshInterval === 600">10m</option>
+    </select>
+    <button @click="toggleDarkMode" class="text-xs p-1">
+      <slot v-if="darkMode">☀</slot>
+      <slot v-else>🌙</slot>
+    </button>
   </div>
 </template>
 
@@ -83,12 +79,11 @@ export default {
 </script>
 
 
-<style scoped>
+<style>
 #settings {
   position: fixed;
-  left: 5px;
-  bottom: 5px;
-  padding: 5px;
+  left: 10px;
+  bottom: 10px;
 }
 
 #settings select:focus {

web/static/index.html

@@ -1 +1 @@
-<!doctype html><html lang="en"><head><meta charset="utf-8"><meta http-equiv="X-UA-Compatible" content="IE=edge"><meta name="viewport" content="width=device-width,initial-scale=1"><link rel="icon" href="/favicon.ico"><title>Health Dashboard | Gatus</title><script defer="defer" src="/js/chunk-vendors.js" type="module"></script><script defer="defer" src="/js/app.js" type="module"></script><link href="/css/app.css" rel="stylesheet"><script defer="defer" src="/js/chunk-vendors-legacy.js" nomodule></script><script defer="defer" src="/js/app-legacy.js" nomodule></script></head><body class="dark:bg-gray-900"><noscript><strong>Enable JavaScript to view this page.</strong></noscript><div id="app"></div></body></html>
+<!doctype html><html lang="en"><head><meta charset="utf-8"/><title>Health Dashboard | Gatus</title><meta http-equiv="X-UA-Compatible" content="IE=edge"><meta name="viewport" content="width=device-width,initial-scale=1"><link rel="icon" href="/favicon.ico"><script defer="defer" src="/js/chunk-vendors.js" type="module"></script><script defer="defer" src="/js/app.js" type="module"></script><link href="/css/app.css" rel="stylesheet"><script defer="defer" src="/js/chunk-vendors-legacy.js" nomodule></script><script defer="defer" src="/js/app-legacy.js" nomodule></script></head><body class="dark:bg-gray-900"><noscript><strong>Enable JavaScript to view this page.</strong></noscript><div id="app"></div></body></html>