Allow predefining targets at startup

.golangci.yml

@@ -0,0 +1,76 @@
+run:
+  # default concurrency is a available CPU number
+  concurrency: 4
+
+  # timeout for analysis, e.g. 30s, 5m, default is 1m
+  timeout: 5m
+
+  # exit code when at least one issue was found, default is 1
+  issues-exit-code: 1
+
+  # include test files or not, default is true
+  tests: true
+
+linters-settings:
+  lll:
+    line-length: 250
+  golint:
+    min-confidence: 0
+  gomnd:
+    settings:
+      mnd:
+        # don't include the "operation" and "assign"
+        checks: argument,case,condition,return
+  govet:
+    check-shadowing: false
+
+  nolintlint:
+    allow-leading-space: false
+    allow-unused: false # report any unused nolint directives
+    require-specific: true # don't require nolint directives to be specific about which linter is being skipped
+
+  maligned:
+    # print struct with more effective memory layout or not, false by default
+    suggest-new: true
+linters:
+  disable-all: true
+  enable:
+    - bodyclose
+    - deadcode
+    - depguard
+    - dogsled
+    - dupl
+    - errcheck
+    - exhaustive
+    - funlen
+    - gochecknoinits
+    - goconst
+    - gocritic
+    - gocyclo
+    - gofmt
+    - goimports
+    - gomnd
+    - goprintffuncname
+    - gosec
+    - gosimple
+    - govet
+    - ineffassign
+    - interfacer
+    - lll
+    - maligned
+    - misspell
+    - nakedret
+    - noctx
+    - nolintlint
+    - rowserrcheck
+    - scopelint
+    - staticcheck
+    - structcheck
+    - stylecheck
+    - typecheck
+    - unconvert
+    - unparam
+    - unused
+    - varcheck
+    - whitespace
+    - wsl

.goreleaser.yml

@@ -12,6 +12,10 @@ builds:
 - env:
   - CGO_ENABLED=0
   - GO111MODULE=on
+  ldflags:
+    - -s -w -X github.com/rb3ckers/trafficmirror.Version={{.Version}}
+    - -X github.com/rb3ckers/trafficmirror.Commit={{.Commit}}
+    - -X github.com/rb3ckers/trafficmirror.Date={{.Date}}
 checksum:
   name_template: checksums.txt
 snapshot:
@@ -23,14 +27,17 @@ changelog:
     - "^docs:"
     - "^test:"
 dockers:
-- extra_files:
-  - datatypes/
-  - go.mod
-  - go.sum
-  - main.go
-  - rootfs/
-  image_templates:
-  - docker.io/stackstate/trafficmirror:latest
-  - docker.io/stackstate/trafficmirror:{{ .Tag }}
-  - docker.io/stackstate/trafficmirror:v{{ .Major }}
-  - docker.io/stackstate/trafficmirror:v{{ .Major }}.{{ .Minor }}
+  -
+    goos: linux
+    goarch: amd64
+    dockerfile: Dockerfile.goreleaser
+    build_flag_templates:
+      - "--label=org.opencontainers.image.created={{.Date}}"
+      - "--label=org.opencontainers.image.title={{.ProjectName}}"
+      - "--label=org.opencontainers.image.revision={{.FullCommit}}"
+      - "--label=org.opencontainers.image.version={{.Version}}"
+    image_templates:
+    - quay.io/stackstate/trafficmirror:latest
+    - quay.io/stackstate/trafficmirror:{{ .Tag }}
+    - quay.io/stackstate/trafficmirror:v{{ .Major }}
+    - quay.io/stackstate/trafficmirror:v{{ .Major }}.{{ .Minor }}

Dockerfile.goreleaser

@@ -0,0 +1,6 @@
+FROM gcr.io/distroless/static:nonroot
+WORKDIR /
+COPY trafficmirror .
+USER nonroot:nonroot
+
+ENTRYPOINT ["/trafficmirror"]

cmd/root.go

@@ -0,0 +1,152 @@
+package cmd
+
+import (
+	"context"
+	"fmt"
+	"log"
+	"os"
+	"os/signal"
+	"syscall"
+
+	"github.com/hierynomus/taipan"
+	home "github.com/mitchellh/go-homedir"
+	"github.com/rb3ckers/trafficmirror/internal/config"
+	"github.com/rb3ckers/trafficmirror/internal/proxy"
+	"github.com/rs/zerolog"
+	"github.com/spf13/cobra"
+)
+
+var (
+	Version string
+	Commit  string
+	Date    string
+)
+
+var EnvPrefix = "TRAFFICMIRROR_"
+
+func RootCommand(cfg *config.Config) *cobra.Command {
+	var verbosity int
+
+	cmd := &cobra.Command{
+		Use:   "trafficmirror",
+		Short: "Runs Traffic Mirror",
+		Long: `
+HTTP proxy that:
+* sends requests to a main endpoint from which the response is returned
+* can mirror the requests to any additional number of endpoints
+
+Additional targets are configured via PUT/DELETE on the '/targets?url=<endpoint>'.
+`,
+		Version: fmt.Sprintf("%s (Built on: %s, Commit: %s)", Version, Date, Commit),
+		PersistentPreRunE: func(cmd *cobra.Command, args []string) error {
+			switch verbosity {
+			case 0:
+				// Nothing to do
+			case 1:
+				zerolog.SetGlobalLevel(zerolog.InfoLevel)
+			case 2: //nolint:gomnd
+				zerolog.SetGlobalLevel(zerolog.DebugLevel)
+			default:
+				zerolog.SetGlobalLevel(zerolog.TraceLevel)
+			}
+
+			return nil
+		},
+		RunE: func(cmd *cobra.Command, args []string) error {
+			PrintUsage(cfg)
+			if err := RunProxy(cfg); err != nil {
+				return err
+			}
+
+			return nil
+		},
+	}
+
+	cmd.PersistentFlags().CountVarP(&verbosity, "verbose", "v", "Print more verbose logging")
+
+	cmd.Flags().StringP("listen", "l", ":8080", "Address to listen on and mirror traffic from")
+	cmd.Flags().StringP("main", "m", "http://localhost:8888", "Main proxy target, its responses will be returned to the client")
+	cmd.Flags().String("targets", "targets", "Path on which additional targets to mirror to can be added/deleted/listed via PUT, DELETE and GET")
+	cmd.Flags().String("targets-address", "", "Address on which the targets endpoint is made available. Leave empty to expose it on the address that is being mirrored")
+	cmd.Flags().String("username", "", "Username to protect the configuration 'targets' endpoint with.")
+	cmd.Flags().String("password", "", "Password to protect the configuration 'targets' endpoint with.")
+	cmd.Flags().String("passwordFile", "", "Provide a file that contains username/password to protect the configuration 'targets' endpoint. Contains 1 username/password combination separated by ':'.")
+	cmd.Flags().Int("fail-after", 30, "Remove a target when it has been failing for this many minutes.") //nolint:gomnd
+	cmd.Flags().Int("retry-after", 1, "After 5 successive failures a target is temporarily disabled, it will be retried after this many minutes.")
+	cmd.Flags().StringSlice("mirror", []string{}, "Start with mirroring traffic to provided targets")
+
+	return cmd
+}
+
+func RunProxy(cfg *config.Config) error {
+	sigs := make(chan os.Signal, 1)
+	done := make(chan bool, 1)
+
+	signal.Notify(sigs, syscall.SIGINT, syscall.SIGTERM)
+
+	p := proxy.NewProxy(cfg)
+
+	go func() {
+		sig := <-sigs
+		log.Printf("Received signal '%s', exiting\n", sig)
+
+		if err := p.Stop(); err != nil {
+			panic(err)
+		}
+
+		done <- true
+	}()
+
+	if err := p.Start(context.Background()); err != nil {
+		return err
+	}
+
+	<-done
+
+	return nil
+}
+
+func Execute(ctx context.Context) {
+	cfg := &config.Config{}
+	cmd := RootCommand(cfg)
+
+	homeFolder, err := home.Expand("~/.trafficmirror")
+	if err != nil {
+		fmt.Printf("%s", err)
+		os.Exit(1)
+	}
+
+	zerolog.SetGlobalLevel(zerolog.ErrorLevel)
+
+	taipanConfig := &taipan.Config{
+		DefaultConfigName:  "trafficmirror",
+		ConfigurationPaths: []string{".", homeFolder},
+		EnvironmentPrefix:  EnvPrefix,
+		AddConfigFlag:      true,
+		ConfigObject:       cfg,
+		PrefixCommands:     true,
+	}
+
+	t := taipan.New(taipanConfig)
+	t.Inject(cmd)
+
+	if err := cmd.ExecuteContext(ctx); err != nil {
+		fmt.Printf("🎃 %s\n", err)
+		os.Exit(1)
+	}
+}
+
+func PrintUsage(cfg *config.Config) {
+	var targetsText string
+	if cfg.TargetsListenAddress != "" {
+		targetsText = fmt.Sprintf("http://%s/%s", cfg.TargetsListenAddress, cfg.TargetsEndpoint)
+	} else {
+		targetsText = fmt.Sprintf("http://%s/%s", cfg.ListenAddress, cfg.TargetsEndpoint)
+	}
+
+	fmt.Printf("Add/remove/list mirror targets via PUT/DELETE/GET at %s:\n", targetsText)
+	fmt.Printf("List  : curl %s\n", targetsText)
+	fmt.Printf("Add   : curl -X PUT %s?url=http://localhost:5678\n", targetsText)
+	fmt.Printf("Remove: curl -X DELETE %s?url=http://localhost:5678\n", targetsText)
+	fmt.Println()
+}