Add flaky-service

.github/workflows/flaky-service.yaml

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+name: flaky-service
+
+on:
+  push:
+    branches: [ main ]
+    paths:
+      - .github/workflows/flaky-service.yaml
+      - flaky-service/**
+  pull_request:
+    branches: [ main ]
+    paths:
+      - .github/workflows/flaky-service.yaml
+      - flaky-service/**
+  workflow_dispatch:
+
+concurrency:
+  group: ${{ github.workflow }}-${{ github.ref }}
+  cancel-in-progress: true
+
+env:
+  REGISTRY: europe-north1-docker.pkg.dev/nais-io/nais/images
+
+jobs:
+  build_push_sign:
+    runs-on: ubuntu-latest
+    permissions:
+      contents: read
+      id-token: write
+    steps:
+      - uses: actions/checkout@v4
+      - uses: nais/platform-build-push-sign@main
+        id: image
+        with:
+          context: ./flaky-service
+          name: flaky-service
+          dockerfile: ./Dockerfile
+          google_service_account: gh-examples
+          push: ${{ github.actor != 'dependabot[bot]' }}
+          workload_identity_provider: ${{ secrets.NAIS_IO_WORKLOAD_IDENTITY_PROVIDER }}
+    outputs:
+      version: ${{ steps.image.outputs.version }}
+  rollout:
+    permissions:
+      id-token: write
+    name: Deploy to NAIS
+    needs: ["build_push_sign"]
+    runs-on: ubuntu-latest
+    if: github.ref == 'refs/heads/main'
+    steps:
+    - uses: actions/checkout@v4
+    - uses: nais/deploy/actions/deploy@v2
+      env:
+        CLUSTER: dev-gcp
+        PRINT_PAYLOAD: "true"
+        RESOURCE: "./flaky-service/.nais/unleash.yaml,./flaky-service/.nais/app.yaml"
+        VAR: image=europe-north1-docker.pkg.dev/nais-io/nais/images/flaky-service:${{ needs.build_push_sign.outputs.version }},namespace=nais

flaky-service/.nais/app.yaml

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+---
+apiVersion: nais.io/v1alpha1
+kind: Application
+metadata:
+  name: flaky-service
+  namespace: {{ namespace }}
+  labels:
+    team: {{ namespace }}
+spec:
+  image: {{ image }}
+  port: 8080
+  prometheus:
+    enabled: false
+  envFrom:
+    - secret: flaky-service-unleash-api-token
+  accessPolicy:
+    outbound:
+      external:
+        - host: nais-demo-unleash-api.nav.cloud.nais.io
+  replicas:
+    max: 1
+    min: 1

flaky-service/.nais/unleash.yaml

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+apiVersion: unleash.nais.io/v1
+kind: ApiToken
+metadata:
+  name: flaky-service
+  namespace: {{ namespace }}
+  labels:
+    team: {{ namespace }}
+spec:
+    unleashInstance:
+      apiVersion: unleash.nais.io/v1
+      kind: RemoteUnleash
+      name: nais-demo
+    secretName: flaky-service-unleash-api-token
+    environment: development

flaky-service/Dockerfile

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+FROM golang:1.22-alpine as builder
+RUN apk add --no-cache git make curl build-base
+ENV GOOS=linux
+WORKDIR /src
+COPY . /src/
+RUN go mod download
+RUN go build -o bin/flaky-service *.go
+
+FROM alpine:3.18
+RUN apk add --no-cache ca-certificates tzdata
+RUN export PATH=$PATH:/app
+WORKDIR /app
+COPY --from=builder /src/bin/flaky-service /app/flaky-service
+CMD ["/app/flaky-service"]

flaky-service/Makefile

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+flaky-service:
+	go build -o bin/flaky-service *.go

flaky-service/README.md

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+# Flaky Service
+
+The Flaky Service is a simple service that aims to simulate flaky behavior in a service oriented architecture.
+
+## Architecture
+
+The service is a simple HTTP server that listens on port `8080` by default written in Go. It has a single endpoint that returns a `200 OK` response for good requests and a `500 Server Error` response for errors.
+
+The flakiness is simulated by randomly returning a `500 Server Error` response for a percentage of requests. The flakiness limit can be adjusted using the Unleash feature toggle mentioned below.
+
+## Endpoint
+
+The service has only one endpoint:
+
+### `/`
+
+- Returns a `200 OK {"message": "hello, world"}` response for good requests.
+- Returns a `500 Server Error {"error": "server error"}` response for errors.
+
+## Adjusting Flakiness
+
+The flakiness of the service can be adjusted using the Unleash feature toggle. The service checks the `flaky-service.flakiness-limit` feature toggle to determine the flakiness limit. If the feature toggle is not present, the service defaults to a flakiness limit of `50%`.

flaky-service/config.go

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+package main
+
+import (
+	"fmt"
+	"log/slog"
+	"net/http"
+	"strconv"
+	"strings"
+
+	"github.com/Unleash/unleash-client-go/v3"
+	"github.com/Unleash/unleash-client-go/v3/api"
+)
+
+const (
+	AppName               = "flaky-service"
+	unleashDefaultProject = "default"
+	unleashDefaultEnv     = "development"
+	unleashDefaultType    = "client"
+
+	toggleFlakinessLevelName    = "flaky-service.flakiness-level"
+	toggleFlakinessLevelDefault = 50
+)
+
+type Config struct {
+	Server  *ServerConfig
+	Unleash *UnleashConfig
+}
+
+type ServerConfig struct {
+	Port string `env:"PORT, default=8080"`
+	Host string `env:"HOST, default=0.0.0.0"`
+}
+
+type UnleashConfig struct {
+	ClientType string `env:"UNLEASH_SERVER_API_TYPE, default=client"`
+	Projects   string `env:"UNLEASH_SERVER_API_PROJECTS, default=default"`
+	Env        string `env:"UNLEASH_SERVER_API_ENV, default=development"`
+	Url        string `env:"UNLEASH_SERVER_API_URL"`
+	Token      string `env:"UNLEASH_SERVER_API_TOKEN"`
+}
+
+func (c *Config) UnleashInit() {
+	projects := strings.Split(c.Unleash.Projects, ",")
+	project := unleashDefaultProject
+	if len(projects) > 0 {
+		project = projects[0]
+	}
+
+	unleash.Initialize(
+		// unleash.WithListener(&unleash.DebugListener{}),
+		unleash.WithAppName(AppName),
+		unleash.WithEnvironment(c.Unleash.Env),
+		unleash.WithUrl(fmt.Sprintf("%s/api", c.Unleash.Url)),
+		unleash.WithProjectName(project),
+		unleash.WithCustomHeaders(http.Header{"Authorization": {fmt.Sprintf("Bearer %s", c.Unleash.Token)}}),
+	)
+}
+
+func (c *Config) FlakinessLevel() int {
+	variant := unleash.GetVariant(toggleFlakinessLevelName, unleash.WithVariantFallback(api.GetDefaultVariant()))
+
+	if variant == nil {
+		slog.Info("Failed to get variant", "featureToggleName", toggleFlakinessLevelName)
+		return toggleFlakinessLevelDefault
+	}
+
+	if variant.Payload.Type != "number" {
+		slog.Info("Invalid variant payload type", "featureToggleName", toggleFlakinessLevelName, "type", variant.Payload.Type, "value", variant.Payload.Value)
+		return toggleFlakinessLevelDefault
+	}
+
+	value, err := strconv.Atoi(variant.Payload.Value)
+	if err != nil {
+		slog.Info("Failed to parse variant value", "featureToggleName", toggleFlakinessLevelName, "type", variant.Payload.Type, "value", variant.Payload.Value, "error", err)
+		return toggleFlakinessLevelDefault
+	}
+	return value
+}

flaky-service/go.mod

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+module github.com/nais/examples/flaky-service
+
+go 1.22.3
+
+require github.com/joho/godotenv v1.5.1
+
+require (
+	github.com/Masterminds/semver/v3 v3.1.1 // indirect
+	github.com/Unleash/unleash-client-go v0.0.0-20190923201156-aae25c357956
+	github.com/Unleash/unleash-client-go/v3 v3.9.2 // indirect
+	github.com/davecgh/go-spew v1.1.1 // indirect
+	github.com/pmezard/go-difflib v1.0.0 // indirect
+	github.com/sethvargo/go-envconfig v1.0.3 // indirect
+	github.com/stretchr/objx v0.1.1 // indirect
+	github.com/stretchr/testify v1.2.2 // indirect
+	github.com/twmb/murmur3 v1.1.5 // indirect
+	golang.org/x/exp v0.0.0-20240613232115-7f521ea00fb8
+)

flaky-service/go.sum

@@ -0,0 +1,24 @@
+github.com/Masterminds/semver/v3 v3.1.1 h1:hLg3sBzpNErnxhQtUy/mmLR2I9foDujNK030IGemrRc=
+github.com/Masterminds/semver/v3 v3.1.1/go.mod h1:VPu/7SZ7ePZ3QOrcuXROw5FAcLl4a0cBrbBpGY/8hQs=
+github.com/Unleash/unleash-client-go v0.0.0-20190923201156-aae25c357956 h1:KW9P0PdJZyaM/A92zCNzwmLtlu2ZgtTlFRAXmQXwgXQ=
+github.com/Unleash/unleash-client-go v0.0.0-20190923201156-aae25c357956/go.mod h1:89lPmFeGRU6Xv5kYZnN1ByXulB4vHW+UepUYSm8s8ws=
+github.com/Unleash/unleash-client-go/v3 v3.9.2 h1:/Jl61G/kOx+1+MqPuMnC/JvJxdsf52ZDdJvCmXoA2ck=
+github.com/Unleash/unleash-client-go/v3 v3.9.2/go.mod h1:jAf7F2WWpfJbfn1n8bZ74p7hkAhijrqH4TpWoT7kWLc=
+github.com/davecgh/go-spew v1.1.1 h1:vj9j/u1bqnvCEfJOwUhtlOARqs3+rkHYY13jYWTU97c=
+github.com/davecgh/go-spew v1.1.1/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
+github.com/joho/godotenv v1.5.1 h1:7eLL/+HRGLY0ldzfGMeQkb7vMd0as4CfYvUVzLqw0N0=
+github.com/joho/godotenv v1.5.1/go.mod h1:f4LDr5Voq0i2e/R5DDNOoa2zzDfwtkZa6DnEwAbqwq4=
+github.com/nbio/st v0.0.0-20140626010706-e9e8d9816f32/go.mod h1:9wM+0iRr9ahx58uYLpLIr5fm8diHn0JbqRycJi6w0Ms=
+github.com/pmezard/go-difflib v1.0.0 h1:4DBwDE0NGyQoBHbLQYPwSUPoCMWR5BEzIk/f1lZbAQM=
+github.com/pmezard/go-difflib v1.0.0/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZNVY4sRDYZ/4=
+github.com/sethvargo/go-envconfig v1.0.3 h1:ZDxFGT1M7RPX0wgDOCdZMidrEB+NrayYr6fL0/+pk4I=
+github.com/sethvargo/go-envconfig v1.0.3/go.mod h1:JLd0KFWQYzyENqnEPWWZ49i4vzZo/6nRidxI8YvGiHw=
+github.com/stretchr/objx v0.1.1 h1:2vfRuCMp5sSVIDSqO8oNnWJq7mPa6KVP3iPIwFBuy8A=
+github.com/stretchr/objx v0.1.1/go.mod h1:HFkY916IF+rwdDfMAkV7OtwuqBVzrE8GR6GFx+wExME=
+github.com/stretchr/testify v1.2.2 h1:bSDNvY7ZPG5RlJ8otE/7V6gMiyenm9RtJ7IUVIAoJ1w=
+github.com/stretchr/testify v1.2.2/go.mod h1:a8OnRcib4nhh0OaRAV+Yts87kKdq0PP7pXfy6kDkUVs=
+github.com/twmb/murmur3 v1.1.5 h1:i9OLS9fkuLzBXjt6dptlAEyk58fJsSTXbRg3SgVyqgk=
+github.com/twmb/murmur3 v1.1.5/go.mod h1:Qq/R7NUyOfr65zD+6Q5IHKsJLwP7exErjN6lyyq3OSQ=
+golang.org/x/exp v0.0.0-20240613232115-7f521ea00fb8 h1:yixxcjnhBmY0nkL253HFVIm0JsFHwrHdT3Yh6szTnfY=
+golang.org/x/exp v0.0.0-20240613232115-7f521ea00fb8/go.mod h1:jj3sYF3dwk5D+ghuXyeI3r5MFf+NT2An6/9dOA95KSI=
+gopkg.in/h2non/gock.v1 v1.0.10/go.mod h1:KHI4Z1sxDW6P4N3DfTWSEza07YpkQP7KJBfglRMEjKY=

flaky-service/main.go

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+package main
+
+import (
+	"context"
+	"fmt"
+	"log"
+	"log/slog"
+	"net/http"
+
+	"github.com/joho/godotenv"
+	"github.com/sethvargo/go-envconfig"
+	"golang.org/x/exp/rand"
+)
+
+var c Config
+
+func init() {
+	ctx := context.Background()
+
+	err := godotenv.Load()
+	if err != nil {
+		log.Fatal("Error loading .env file", err)
+	}
+
+	if err := envconfig.Process(ctx, &c); err != nil {
+		log.Fatal("Error processing config:", err)
+	}
+
+	c.UnleashInit()
+}
+
+func main() {
+	slog.Info("Starting server", "flakinessLevel", c.Server.Host, "port", c.Server.Port)
+
+	// Start a simple HTTP server
+	http.HandleFunc("/", func(w http.ResponseWriter, r *http.Request) {
+		w.Header().Set("Content-Type", "application/json")
+
+		level := c.FlakinessLevel()
+		slog.Info("Flakiness level", "level", level)
+
+		w.Header().Set("X-Flakiness-Level", fmt.Sprintf("%d", level))
+
+		if rand.Intn(100) < level {
+			w.WriteHeader(http.StatusInternalServerError)
+			w.Write([]byte(`{"error": "Internal Server Error"}`))
+			return
+		}
+
+		w.WriteHeader(http.StatusOK)
+		w.Write([]byte(`{"message": "Hello, World!"}`))
+	})
+
+	log.Fatal(http.ListenAndServe(fmt.Sprintf("%s:%s", c.Server.Host, c.Server.Port), nil))
+}