Merge pull request #1 from snapp-incubator/initial-dev

Basic Code Implementation: Initial Branch

.github/workflows/ci.yaml

@@ -0,0 +1,26 @@
+---
+ name: ci
+ on:
+   - push
+ jobs:
+   lint:
+     name: lint
+     runs-on: ubuntu-latest
+     steps:
+       - uses: actions/checkout@v2
+       - name: golangci-lint
+         uses: golangci/golangci-lint-action@v2
+         with:
+           version: latest
+   test:
+     name: test
+     runs-on: ubuntu-latest
+     steps:
+       - uses: actions/checkout@v2
+       - uses: actions/setup-go@v2
+         with:
+           go-version: 1.22
+       - run: go test -v ./... -covermode=atomic -coverprofile=coverage.out
+       - uses: codecov/codecov-action@v1
+         with:
+           files: coverage.out

.gitignore

@@ -0,0 +1,21 @@
+# Binaries for programs and plugins
+*.exe
+*.exe~
+*.dll
+*.so
+*.dylib
+
+# Test binary, built with `go test -c`
+*.test
+
+# Output of the go coverage tool, specifically when used with LiteIDE
+*.out
+
+# Dependency directories (remove the comment below to include it)
+# vendor/
+
+# golang
+.idea/
+
+# config
+config.yaml

.golangci.yml

@@ -0,0 +1,27 @@
+# ---
+# linters:
+#   enable-all: true
+#   disable:
+#     - depguard
+#     # we don't use json with camel-case
+#     - tagliatelle
+#     - nolintlint
+#     # it should improve to support more known patterns
+#     - varnamelen
+#     - ireturn
+#     # deprecated linters
+#     - maligned
+#     - scopelint
+#     - golint
+#     - ifshort
+#     - interfacer
+#     - exhaustivestruct
+#     - nosnakecase
+#     - varcheck
+#     - deadcode
+#     - structcheck
+#     - gomnd
+#     - execinquery
+#     # temporarily disabled 
+#     - tagalign
+#     - gochecknoglobals

build/package/Dockerfile

@@ -0,0 +1,26 @@
+# Start from the latest golang base image
+FROM golang:alpine AS builder
+
+# Set the Current Working Directory inside the container
+WORKDIR /app
+
+# Copy go mod and sum files
+COPY go.mod go.sum ./
+
+# Download all dependencies. Dependencies will be cached if the go.mod and go.sum files are not changed
+RUN go mod download
+
+# Copy the source from the current directory to the Working Directory inside the container
+COPY . .
+
+# Build the Go app
+WORKDIR /app/cmd/nats-blackbox-exporter
+RUN go build -o /nats-blackbox-exporter
+
+FROM alpine:latest
+
+WORKDIR /app/
+
+COPY --from=builder /nats-blackbox-exporter .
+
+ENTRYPOINT ["./nats-blackbox-exporter"]

cmd/nats-blackbox-exporter/main.go

@@ -0,0 +1,7 @@
+package main
+
+import "github.com/snapp-incubator/nats-blackbox-exporter/internal/cmd"
+
+func main() {
+	cmd.Execute()
+}

go.mod

@@ -0,0 +1,30 @@
+module github.com/snapp-incubator/nats-blackbox-exporter
+
+go 1.22.0
+
+require (
+	github.com/knadh/koanf v1.5.0
+	github.com/knadh/koanf/v2 v2.1.1
+	github.com/nats-io/nats.go v1.31.0
+	github.com/spf13/cobra v1.8.0
+	github.com/tidwall/pretty v1.2.1
+	go.uber.org/zap v1.17.0
+)
+
+require (
+	github.com/fatih/structs v1.1.0 // indirect
+	github.com/fsnotify/fsnotify v1.4.9 // indirect
+	github.com/go-viper/mapstructure/v2 v2.0.0-alpha.1 // indirect
+	github.com/inconshreveable/mousetrap v1.1.0 // indirect
+	github.com/klauspost/compress v1.17.0 // indirect
+	github.com/mitchellh/copystructure v1.2.0 // indirect
+	github.com/mitchellh/reflectwalk v1.0.2 // indirect
+	github.com/nats-io/nkeys v0.4.5 // indirect
+	github.com/nats-io/nuid v1.0.1 // indirect
+	github.com/spf13/pflag v1.0.5 // indirect
+	go.uber.org/atomic v1.7.0 // indirect
+	go.uber.org/multierr v1.6.0 // indirect
+	golang.org/x/crypto v0.6.0 // indirect
+	golang.org/x/sys v0.5.0 // indirect
+	gopkg.in/yaml.v3 v3.0.1 // indirect
+)

internal/client/client.go

@@ -0,0 +1,87 @@
+package client
+
+import (
+	"time"
+
+	"github.com/nats-io/nats.go"
+	"go.uber.org/zap"
+)
+
+type Client struct {
+	Conn   *nats.Conn
+	Logger *zap.Logger
+	Config Config
+}
+
+func Connect(logger *zap.Logger, cfg Config) *nats.Conn {
+	nc, err := nats.Connect(cfg.URL)
+	if err != nil {
+		logger.Fatal("nats connection failed", zap.Error(err))
+	}
+
+	logger.Info("nats connection successful",
+		zap.String("connected-addr", nc.ConnectedAddr()),
+		zap.Strings("discovered-servers", nc.DiscoveredServers()))
+
+	nc.SetDisconnectErrHandler(func(_ *nats.Conn, err error) {
+		logger.Fatal("nats disconnected", zap.Error(err))
+	})
+
+	nc.SetReconnectHandler(func(_ *nats.Conn) {
+		logger.Warn("nats reconnected")
+	})
+
+	return nc
+}
+
+func New(nc *nats.Conn, logger *zap.Logger, cfg Config) *Client {
+	return &Client{
+		Conn:   nc,
+		Logger: logger,
+		Config: cfg,
+	}
+}
+
+func (c *Client) StartMessaging() {
+	go c.Subscribe("")
+	go c.Publish("")
+}
+
+func (c *Client) Publish(subject string) {
+	if subject == "" {
+		subject = c.Config.DefaultSubject
+	}
+	for {
+		msg, err := c.Conn.Request(subject, []byte("Hello, NATS!"), c.Config.RequestTimeout)
+		if err != nil {
+			if err == nats.ErrTimeout {
+				c.Logger.Error("Request timeout: No response received within the timeout period.")
+			} else if err == nats.ErrNoResponders {
+				c.Logger.Error("Request failed: No responders available for the subject.")
+			} else {
+				c.Logger.Error("Request failed: %v", zap.Error(err))
+			}
+		} else {
+			c.Logger.Info("Received response successfully:", zap.ByteString("response", msg.Data))
+		}
+
+		time.Sleep(c.Config.PublishInterval)
+	}
+}
+
+func (c *Client) Subscribe(subject string) {
+	if subject == "" {
+		subject = c.Config.DefaultSubject
+	}
+	_, err := c.Conn.Subscribe(subject, func(msg *nats.Msg) {
+		c.Logger.Info("Received message successfully: ", zap.ByteString("message", msg.Data))
+		err := c.Conn.Publish(msg.Reply, []byte("Hi!"))
+		if err != nil {
+			c.Logger.Error("Failed to publish response: %v", zap.Error(err))
+		}
+	})
+	if err != nil {
+		c.Logger.Error("Failed to subscribe to subject 'subject1': %v", zap.Error(err))
+	}
+
+}

internal/client/config.go

@@ -0,0 +1,10 @@
+package client
+
+import "time"
+
+type Config struct {
+	URL             string        `json:"url,omitempty"            koanf:"url"`
+	PublishInterval time.Duration `json:"publish_interval" koanf:"publish_interval"`
+	RequestTimeout  time.Duration `json:"request_timeout" koanf:"request_timeout"`
+	DefaultSubject  string        `json:"default_subject" koanf:"default_subject"`
+}

internal/cmd/main.go

@@ -0,0 +1,25 @@
+package cmd
+
+import (
+	"os"
+	"os/signal"
+	"syscall"
+
+	"github.com/snapp-incubator/nats-blackbox-exporter/internal/client"
+	"github.com/snapp-incubator/nats-blackbox-exporter/internal/config"
+	"go.uber.org/zap"
+)
+
+func main(cfg config.Config, logger *zap.Logger) {
+	natsConfig := cfg.NATS
+
+	natsClient := client.New(client.Connect(logger, natsConfig), logger, natsConfig)
+
+	natsClient.StartMessaging()
+
+	sig := make(chan os.Signal, 1)
+	signal.Notify(sig, syscall.SIGINT, syscall.SIGTERM)
+	<-sig
+	logger.Info("Received termination signal. Exiting...")
+	os.Exit(0)
+}

internal/cmd/root.go

@@ -0,0 +1,31 @@
+package cmd
+
+import (
+	"os"
+
+	"github.com/snapp-incubator/nats-blackbox-exporter/internal/config"
+	"github.com/snapp-incubator/nats-blackbox-exporter/internal/logger"
+	"github.com/spf13/cobra"
+)
+
+// ExitFailure status code.
+const ExitFailure = 1
+
+func Execute() {
+	cfg := config.New()
+
+	logger := logger.New(cfg.Logger)
+
+	// nolint: exhaustruct
+	root := &cobra.Command{
+		Use:   "nats-blackbox-exporter",
+		Short: "ping pong with nats broker",
+		Run: func(_ *cobra.Command, _ []string) {
+			main(cfg, logger)
+		},
+	}
+
+	if err := root.Execute(); err != nil {
+		os.Exit(ExitFailure)
+	}
+}

internal/config/config.go

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+package config
+
+import (
+	"encoding/json"
+	"log"
+	"strings"
+
+	"github.com/knadh/koanf/parsers/yaml"
+	"github.com/knadh/koanf/providers/env"
+	"github.com/knadh/koanf/providers/file"
+	"github.com/knadh/koanf/providers/structs"
+	"github.com/knadh/koanf/v2"
+	"github.com/snapp-incubator/nats-blackbox-exporter/internal/client"
+	"github.com/snapp-incubator/nats-blackbox-exporter/internal/logger"
+	"github.com/tidwall/pretty"
+)
+
+const (
+	// Prefix indicates environment variables prefix.
+	Prefix = "nbe_"
+)
+
+type (
+	// Config holds all configurations.
+	Config struct {
+		Logger logger.Config `json:"logger,omitempty" koanf:"logger"`
+		NATS   client.Config `json:"nats,omitempty" koanf:"nats"`
+	}
+)
+
+// New reads configuration with koanf.
+func New() Config {
+	var instance Config
+
+	k := koanf.New(".")
+
+	// load default configuration from file
+	if err := k.Load(structs.Provider(Default(), "koanf"), nil); err != nil {
+		log.Fatalf("error loading default: %s", err)
+	}
+
+	// load configuration from file
+	if err := k.Load(file.Provider("config.yaml"), yaml.Parser()); err != nil {
+		log.Printf("error loading config.yaml")
+	}
+
+	// load environment variables
+	if err := k.Load(env.Provider(Prefix, ".", func(s string) string {
+		return strings.ReplaceAll(strings.ToLower(
+			strings.TrimPrefix(s, Prefix)), "__", ".")
+	}), nil); err != nil {
+		log.Printf("error loading environment variables: %s", err)
+	}
+
+	if err := k.Unmarshal("", &instance); err != nil {
+		log.Fatalf("error unmarshalling config: %s", err)
+	}
+
+	indent, err := json.MarshalIndent(instance, "", "\t")
+	if err != nil {
+		log.Fatalf("error marshalling config to json: %s", err)
+	}
+
+	indent = pretty.Color(indent, nil)
+	tmpl := `
+	================ Loaded Configuration ================
+	%s
+	======================================================
+	`
+	log.Printf(tmpl, string(indent))
+
+	return instance
+}