[1/x] Adds a CLI for entrypoint

Dockerfile

@@ -68,4 +68,4 @@ COPY --from=builder /build/dependencies/lib/ /lib/
 COPY --from=builder /build/ceph-api /bin/ceph-api
 WORKDIR /bin
 
-CMD ["ceph-api"]
+ENTRYPOINT ["/bin/ceph-api", "serve"]

README.md

@@ -36,7 +36,7 @@ In this way Ceph API could be deployed anywhere with access to Ceph `mon`.
    CEPH_DEMO_TAG=latest docker-compose up
    ```
 
-   Ceph-API docker container starts with both REST and grpc APIs on port `:9969` and creates default admin account with both username `admin` and password `yoursecretpass`.
+   Ceph-API docker container runs `ceph-api serve`, starts both REST and grpc APIs on port `:9969`, and creates default admin account with both username `admin` and password `yoursecretpass`.
 
 2. Get API Access token:
 
@@ -70,7 +70,17 @@ In this way Ceph API could be deployed anywhere with access to Ceph `mon`.
 ## Config
 
 By default, both gRPC and REST API are exposed on the same port `:9969`. See all default configurations in [`pkg/config/config.yaml`](./pkg/config/config.yaml).
-To override default configuration, create similar YAML file and provide its path to application binary as `-config` or `-config-override` arguments. The latter will override the former and can be useful to manage secret values (mount k8s secret to this path).
+Start the server with `ceph-api serve`. To override default configuration, create similar YAML file and provide its path with the `--config` or `--config-override` arguments. The latter will override the former and can be useful to manage secret values (mount k8s secret to this path).
+
+```shell
+ceph-api serve --config /path/to/config.yaml --config-override /path/to/override.yaml
+```
+
+The Docker image uses `/bin/ceph-api serve` as its entrypoint, so server configuration flags can be passed directly after the image name:
+
+```shell
+docker run ghcr.io/clyso/ceph-api:latest --config /path/to/config.yaml
+```
 
 Additionally, any config parameter can be set with envar in following format:
 `CFG_<yaml properties seprated with _>=<value>`. For example:
@@ -85,16 +95,16 @@ app:
 API config uses the following precedence order:
 
 1. Default [`config.yaml`](./pkg/config/config.yaml)
-2. YAML file provided in `-config`
-3. YAML file provided in `-config-override`
+2. YAML file provided in `--config`
+3. YAML file provided in `--config-override`
 4. Envars
 
 ## Mock Mode
 
 To run Ceph API in mock mode without a real Ceph cluster:
 
 ```shell
-CFG_APP_CREATEADMIN=true CFG_APP_ADMINUSERNAME=admin CFG_APP_ADMINPASSWORD=yoursecretpass go run -tags=mock ./cmd/ceph-api/main.go
+CFG_APP_CREATEADMIN=true CFG_APP_ADMINUSERNAME=admin CFG_APP_ADMINPASSWORD=yoursecretpass go run -tags=mock ./cmd/ceph-api serve
 ```
 
 ## Security

cmd/ceph-api/main.go

@@ -1,55 +1,19 @@
 package main
 
 import (
-	"context"
-	"flag"
 	"os"
-	"os/signal"
-	"syscall"
 
-	"github.com/clyso/ceph-api/pkg/app"
-	"github.com/clyso/ceph-api/pkg/config"
-	"github.com/rs/zerolog"
 	stdlog "github.com/rs/zerolog/log"
 )
 
 // this information will be collected when built, by -ldflags="-X 'main.version=$(tag)' -X 'main.commit=$(commit)'".
 var (
-	version            = "development"
-	commit             = "not set"
-	configPath         = flag.String("config", "", "set path to config directory")
-	configOverridePath = flag.String("config-override", "", "set path to config override directory")
+	version = "development"
+	commit  = "not set"
 )
 
 func main() {
-	flag.Parse()
-	var configs []config.Src
-	if configPath != nil && *configPath != "" {
-		configs = append(configs, config.Path(*configPath))
-	}
-	if configOverridePath != nil && *configOverridePath != "" {
-		configs = append(configs, config.Path(*configOverridePath))
-	}
-
-	ctx, cancel := context.WithCancel(context.Background())
-	signals := make(chan os.Signal, 1)
-	signal.Notify(signals, syscall.SIGHUP, syscall.SIGINT, syscall.SIGQUIT, syscall.SIGABRT, syscall.SIGTERM)
-	go func() {
-		<-signals
-		zerolog.Ctx(ctx).Info().Msg("received shutdown signal.")
-		cancel()
-	}()
-	var conf config.Config
-	err := config.Get(&conf, configs...)
-	if err != nil {
-		stdlog.Fatal().Err(err).Msg("critical error. Unable to read app config")
-	}
-
-	err = app.Start(ctx, conf, config.Build{
-		Version: version,
-		Commit:  commit,
-	})
-	if err != nil {
+	if err := newRootCmd().Execute(); err != nil {
 		stdlog.Err(err).Msg("critical error. Shutdown application")
 		os.Exit(1)
 	}

cmd/ceph-api/root.go

@@ -0,0 +1,30 @@
+package main
+
+import "github.com/spf13/cobra"
+
+type rootOptions struct {
+	configPath         string
+	configOverridePath string
+}
+
+func newRootCmd() *cobra.Command {
+	opts := &rootOptions{}
+
+	cmd := &cobra.Command{
+		Use:           "ceph-api",
+		Short:         "Ceph API server and client",
+		SilenceUsage:  true,
+		SilenceErrors: true,
+		RunE: func(cmd *cobra.Command, args []string) error {
+			return runServe(cmd.Context(), opts)
+		},
+	}
+
+	cmd.PersistentFlags().StringVar(&opts.configPath, "config", "", "set path to config directory")
+	cmd.PersistentFlags().StringVar(&opts.configOverridePath, "config-override", "", "set path to config override directory")
+
+	cmd.AddCommand(newServeCmd(opts))
+	cmd.AddCommand(newVersionCmd())
+
+	return cmd
+}

cmd/ceph-api/serve.go

@@ -0,0 +1,64 @@
+package main
+
+import (
+	"context"
+	"os"
+	"os/signal"
+	"syscall"
+
+	"github.com/clyso/ceph-api/pkg/app"
+	"github.com/clyso/ceph-api/pkg/config"
+	"github.com/rs/zerolog"
+	"github.com/spf13/cobra"
+)
+
+func newServeCmd(opts *rootOptions) *cobra.Command {
+	return &cobra.Command{
+		Use:   "serve",
+		Short: "Start the ceph-api server",
+		RunE: func(cmd *cobra.Command, args []string) error {
+			return runServe(cmd.Context(), opts)
+		},
+	}
+}
+
+func runServe(parent context.Context, opts *rootOptions) error {
+	var configs []config.Src
+	if opts.configPath != "" {
+		configs = append(configs, config.Path(opts.configPath))
+	}
+	if opts.configOverridePath != "" {
+		configs = append(configs, config.Path(opts.configOverridePath))
+	}
+
+	ctx, cancel := signalContext(parent)
+	defer cancel()
+
+	var conf config.Config
+	if err := config.Get(&conf, configs...); err != nil {
+		return err
+	}
+
+	return app.Start(ctx, conf, config.Build{
+		Version: version,
+		Commit:  commit,
+	})
+}
+
+func signalContext(parent context.Context) (context.Context, context.CancelFunc) {
+	ctx, cancel := context.WithCancel(parent)
+	signals := make(chan os.Signal, 1)
+	signal.Notify(signals, syscall.SIGHUP, syscall.SIGINT, syscall.SIGQUIT, syscall.SIGABRT, syscall.SIGTERM)
+
+	go func() {
+		select {
+		case <-signals:
+			zerolog.Ctx(ctx).Info().Msg("received shutdown signal.")
+			cancel()
+		case <-ctx.Done():
+		}
+		signal.Stop(signals)
+	}()
+
+	return ctx, cancel
+}

cmd/ceph-api/version.go

@@ -0,0 +1,18 @@
+package main
+
+import (
+	"fmt"
+
+	"github.com/spf13/cobra"
+)
+
+func newVersionCmd() *cobra.Command {
+	return &cobra.Command{
+		Use:   "version",
+		Short: "Print version information",
+		RunE: func(cmd *cobra.Command, args []string) error {
+			_, err := fmt.Fprintf(cmd.OutOrStdout(), "ceph-api %s (%s)\n", version, commit)
+			return err
+		},
+	}
+}

cmd/ceph-api/version_test.go

@@ -0,0 +1,30 @@
+package main
+
+import (
+	"bytes"
+	"testing"
+)
+
+func TestVersionCommand(t *testing.T) {
+	oldVersion := version
+	oldCommit := commit
+	version = "v1.2.3"
+	commit = "abc123"
+	t.Cleanup(func() {
+		version = oldVersion
+		commit = oldCommit
+	})
+
+	cmd := newRootCmd()
+	buf := new(bytes.Buffer)
+	cmd.SetOut(buf)
+	cmd.SetArgs([]string{"version"})
+
+	if err := cmd.Execute(); err != nil {
+		t.Fatalf("Execute() error = %v", err)
+	}
+
+	if got, want := buf.String(), "ceph-api v1.2.3 (abc123)\n"; got != want {
+		t.Fatalf("version output = %q, want %q", got, want)
+	}
+}

deploy/ceph-api/templates/deployment.yaml

@@ -38,9 +38,10 @@ spec:
             {{- end }}
           command:
             - "ceph-api"
-            - "-config"
+            - "serve"
+            - "--config"
             - "/bin/config/config.yaml"
-            - "-config-override"
+            - "--config-override"
             - "/bin/config/override.yaml"
           volumeMounts:
             - mountPath: /bin/config/config.yaml

go.mod

@@ -33,6 +33,7 @@ require (
 
 require (
 	github.com/soheilhy/cmux v0.1.5
+	github.com/spf13/cobra v1.8.0
 	go.opentelemetry.io/otel/exporters/otlp/otlptrace/otlptracehttp v1.24.0
 	golang.org/x/oauth2 v0.20.0
 )
@@ -87,7 +88,6 @@ require (
 	github.com/sourcegraph/conc v0.3.0 // indirect
 	github.com/spf13/afero v1.11.0 // indirect
 	github.com/spf13/cast v1.6.0 // indirect
-	github.com/spf13/cobra v1.8.0 // indirect
 	github.com/spf13/pflag v1.0.5 // indirect
 	github.com/subosito/gotenv v1.6.0 // indirect
 	go.opentelemetry.io/contrib/instrumentation/net/http/httptrace/otelhttptrace v0.49.0 // indirect

pkg/rados/production_conn.go

@@ -3,6 +3,7 @@
 package rados
 
 import (
+	"fmt"
 	"strconv"
 
 	"github.com/ceph/go-ceph/rados"
@@ -21,26 +22,26 @@ func NewRadosConn(conf Config) (RadosConnInterface, error) {
 	// Create a real connection.
 	conn, err := rados.NewConnWithUser(conf.User)
 	if err != nil {
-		return nil, err
+		return nil, fmt.Errorf("initialize Ceph/RADOS client for user %q: ensure Ceph libraries are installed and available: %w", conf.User, err)
 	}
 	if conf.MonHost == "" || conf.UserKeyring == "" || conf.RadosTimeout == 0 {
 		err = conn.ReadDefaultConfigFile()
 	} else {
 		err = conn.ParseCmdLineArgs([]string{"--mon-host", conf.MonHost, "--key", conf.UserKeyring, "--client_mount_timeout", "3"})
 	}
 	if err != nil {
-		return nil, err
+		return nil, fmt.Errorf("load Ceph/RADOS configuration: provide rados.monHost and rados.userKeyring, or ensure the default Ceph config/keyring files are readable: %w", err)
 	}
 
 	timeout := strconv.FormatFloat(conf.RadosTimeout.Seconds(), 'f', -1, 64)
 	if err = conn.SetConfigOption("rados_osd_op_timeout", timeout); err != nil {
-		return nil, err
+		return nil, fmt.Errorf("configure Ceph/RADOS OSD operation timeout: %w", err)
 	}
 	if err = conn.SetConfigOption("rados_mon_op_timeout", timeout); err != nil {
-		return nil, err
+		return nil, fmt.Errorf("configure Ceph/RADOS monitor operation timeout: %w", err)
 	}
 	if err = conn.Connect(); err != nil {
-		return nil, err
+		return nil, fmt.Errorf("connect to Ceph/RADOS cluster: ensure Ceph config/keyring are valid and monitors are reachable: %w", err)
 	}
 
 	// Wrap the real connection.