Add support for printing published docker image metadata to a file (#17)

cmd/artifact/artifact.go

@@ -0,0 +1,76 @@
+package artifact
+
+import (
+	"encoding/json"
+	"fmt"
+	"io/ioutil"
+	"os"
+	"path/filepath"
+
+	"github.com/pkg/errors"
+)
+
+const (
+	dockerArtifactV1 string = "docker/v1"
+)
+
+type RegistryTypeEnum string
+
+const (
+	Docker RegistryTypeEnum = "Docker"
+	ECR    RegistryTypeEnum = "ECR"
+	GCR    RegistryTypeEnum = "GCR"
+)
+
+type (
+	Image struct {
+		Image  string `json:"image"`
+		Digest string `json:"digest"`
+	}
+	Data struct {
+		RegistryType RegistryTypeEnum `json:"registryType"`
+		RegistryUrl  string           `json:"registryUrl"`
+		Images       []Image          `json:"images"`
+	}
+	DockerArtifact struct {
+		Kind string `json:"kind"`
+		Data Data   `json:"data"`
+	}
+)
+
+func WritePluginArtifactFile(registryType RegistryTypeEnum, artifactFilePath, registryUrl, imageName, digest string, tags []string) error {
+	var images []Image
+	for _, tag := range tags {
+		images = append(images, Image{
+			Image:  fmt.Sprintf("%s:%s", imageName, tag),
+			Digest: digest,
+		})
+	}
+	data := Data{
+		RegistryType: registryType,
+		RegistryUrl:  registryUrl,
+		Images:       images,
+	}
+
+	dockerArtifact := DockerArtifact{
+		Kind: dockerArtifactV1,
+		Data: data,
+	}
+
+	b, err := json.MarshalIndent(dockerArtifact, "", "\t")
+	if err != nil {
+		return errors.Wrap(err, fmt.Sprintf("failed to marshal output %+v", dockerArtifact))
+	}
+
+	dir := filepath.Dir(artifactFilePath)
+	err = os.MkdirAll(dir, 0644)
+	if err != nil {
+		return errors.Wrap(err, fmt.Sprintf("failed to create %s directory for artifact file", dir))
+	}
+
+	err = ioutil.WriteFile(artifactFilePath, b, 0644)
+	if err != nil {
+		return errors.Wrap(err, fmt.Sprintf("failed to write artifact to artifact file %s", artifactFilePath))
+	}
+	return nil
+}

cmd/artifact/artifact.json

@@ -0,0 +1,17 @@
+{
+	"kind": "docker/v1",
+	"data": {
+		"registryType": "Docker",
+		"registryUrl": "https://index.docker.io/",
+		"images": [
+			{
+				"image": "image:a1",
+				"digest": "sha256:22332233"
+			},
+			{
+				"image": "image:latest",
+				"digest": "sha256:22332233"
+			}
+		]
+	}
+}

cmd/artifact/artifact_test.go

@@ -0,0 +1,38 @@
+package artifact
+
+import (
+	"io/ioutil"
+	"testing"
+)
+
+func TestWritePluginArtifactFile(t *testing.T) {
+
+	testFile := t.TempDir() + "got.json"
+
+	err := WritePluginArtifactFile(Docker, testFile, "https://index.docker.io/", "image", "sha256:22332233", []string{"a1", "latest"})
+	if err != nil {
+		t.Error(err)
+		t.FailNow()
+	}
+
+	gotBytes, err := ioutil.ReadFile(testFile)
+	if err != nil {
+		t.Error(err)
+		t.FailNow()
+	}
+
+	wantBytes, err := ioutil.ReadFile("./artifact.json")
+	if err != nil {
+		t.Error(err)
+		t.FailNow()
+	}
+
+	got := string(gotBytes)
+	want := string(wantBytes)
+
+	if got != want {
+		t.Logf("got:%s", got)
+		t.Logf("want:%s", want)
+		t.FailNow()
+	}
+}

cmd/kaniko-docker/main.go

@@ -12,6 +12,7 @@ import (
 	"github.com/urfave/cli"
 
 	kaniko "github.com/drone/drone-kaniko"
+	"github.com/drone/drone-kaniko/cmd/artifact"
 )
 
 const (
@@ -21,6 +22,8 @@ const (
 
 	v1Registry string = "https://index.docker.io/v1/" // Default registry
 	v2Registry string = "https://index.docker.io/v2/" // v2 registry is not supported
+
+	defaultDigestFile string = "/kaniko/digest-file"
 )
 
 var (
@@ -119,6 +122,11 @@ func main() {
 			Usage:  "Cache timeout in hours. Defaults to two weeks.",
 			EnvVar: "PLUGIN_CACHE_TTL",
 		},
+		cli.StringFlag{
+			Name:   "artifact-file",
+			Usage:  "Artifact file location that will be generated by the plugin. This file will include information of docker images that are uploaded by the plugin.",
+			EnvVar: "PLUGIN_ARTIFACT_FILE",
+		},
 	}
 
 	if err := app.Run(os.Args); err != nil {
@@ -146,6 +154,14 @@ func run(c *cli.Context) error {
 			EnableCache:   c.Bool("enable-cache"),
 			CacheRepo:     c.String("cache-repo"),
 			CacheTTL:      c.Int("cache-ttl"),
+			DigestFile:    defaultDigestFile,
+		},
+		Artifact: kaniko.Artifact{
+			Tags:         c.StringSlice("tags"),
+			Repo:         c.String("repo"),
+			Registry:     c.String("registry"),
+			ArtifactFile: c.String("artifact-file"),
+			RegistryType: artifact.Docker,
 		},
 	}
 	return plugin.Exec()

cmd/kaniko-ecr/main.go

@@ -11,12 +11,15 @@ import (
 	"github.com/urfave/cli"
 
 	kaniko "github.com/drone/drone-kaniko"
+	"github.com/drone/drone-kaniko/cmd/artifact"
 )
 
 const (
 	accessKeyEnv     string = "AWS_ACCESS_KEY_ID"
 	secretKeyEnv     string = "AWS_SECRET_ACCESS_KEY"
 	dockerConfigPath string = "/kaniko/.docker/config.json"
+
+	defaultDigestFile string = "/kaniko/digest-file"
 )
 
 var (
@@ -109,6 +112,11 @@ func main() {
 			Usage:  "Cache timeout in hours. Defaults to two weeks.",
 			EnvVar: "PLUGIN_CACHE_TTL",
 		},
+		cli.StringFlag{
+			Name:   "artifact-file",
+			Usage:  "Artifact file location that will be generated by the plugin. This file will include information of docker images that are uploaded by the plugin.",
+			EnvVar: "PLUGIN_ARTIFACT_FILE",
+		},
 	}
 
 	if err := app.Run(os.Args); err != nil {
@@ -135,14 +143,22 @@ func run(c *cli.Context) error {
 			EnableCache:  c.Bool("enable-cache"),
 			CacheRepo:    fmt.Sprintf("%s/%s", c.String("registry"), c.String("cache-repo")),
 			CacheTTL:     c.Int("cache-ttl"),
+			DigestFile:   defaultDigestFile,
+		},
+		Artifact: kaniko.Artifact{
+			Tags:         c.StringSlice("tags"),
+			Repo:         c.String("repo"),
+			Registry:     c.String("registry"),
+			ArtifactFile: c.String("artifact-file"),
+			RegistryType: artifact.ECR,
 		},
 	}
 	return plugin.Exec()
 }
 
 func setupECRAuth(accessKey, secretKey, registry string) error {
 	if registry == "" {
-		return fmt.Errorf("Registry must be specified")
+		return fmt.Errorf("registry must be specified")
 	}
 
 	// If IAM role is used, access key & secret key are not required

cmd/kaniko-gcr/main.go

@@ -11,12 +11,15 @@ import (
 	"github.com/urfave/cli"
 
 	kaniko "github.com/drone/drone-kaniko"
+	"github.com/drone/drone-kaniko/cmd/artifact"
 )
 
 const (
 	// GCR JSON key file path
 	gcrKeyPath     string = "/kaniko/config.json"
 	gcrEnvVariable string = "GOOGLE_APPLICATION_CREDENTIALS"
+
+	defaultDigestFile string = "/kaniko/digest-file"
 )
 
 var (
@@ -105,6 +108,11 @@ func main() {
 			Usage:  "Cache timeout in hours. Defaults to two weeks.",
 			EnvVar: "PLUGIN_CACHE_TTL",
 		},
+		cli.StringFlag{
+			Name:   "artifact-file",
+			Usage:  "Artifact file location that will be generated by the plugin. This file will include information of docker images that are uploaded by the plugin.",
+			EnvVar: "PLUGIN_ARTIFACT_FILE",
+		},
 	}
 
 	if err := app.Run(os.Args); err != nil {
@@ -135,6 +143,14 @@ func run(c *cli.Context) error {
 			EnableCache:  c.Bool("enable-cache"),
 			CacheRepo:    fmt.Sprintf("%s/%s", c.String("registry"), c.String("cache-repo")),
 			CacheTTL:     c.Int("cache-ttl"),
+			DigestFile:   defaultDigestFile,
+		},
+		Artifact: kaniko.Artifact{
+			Tags:         c.StringSlice("tags"),
+			Repo:         c.String("repo"),
+			Registry:     c.String("registry"),
+			ArtifactFile: c.String("artifact-file"),
+			RegistryType: artifact.GCR,
 		},
 	}
 	return plugin.Exec()

kaniko.go

@@ -2,9 +2,12 @@ package kaniko
 
 import (
 	"fmt"
+	"io/ioutil"
 	"os"
 	"os/exec"
 	"strings"
+
+	"github.com/drone/drone-kaniko/cmd/artifact"
 )
 
 type (
@@ -22,11 +25,22 @@ type (
 		EnableCache   bool     // Whether to enable kaniko cache
 		CacheRepo     string   // Remote repository that will be used to store cached layers
 		CacheTTL      int      // Cache timeout in hours
+		DigestFile    string   // Digest file location
+	}
+	// Artifact defines content of artifact file
+	Artifact struct {
+		Tags         []string                  // Docker artifact tags
+		Repo         string                    // Docker artifact repository
+		Registry     string                    // Docker artifact registry
+		RegistryType artifact.RegistryTypeEnum // Rocker artifact registry type
+		ArtifactFile string                    // Artifact file location
+
 	}
 
 	// Plugin defines the Docker plugin parameters.
 	Plugin struct {
-		Build Build // Docker build configuration
+		Build    Build    // Docker build configuration
+		Artifact Artifact // Artifact file content
 	}
 )
 
@@ -82,13 +96,32 @@ func (p Plugin) Exec() error {
 		cmdArgs = append(cmdArgs, fmt.Sprintf("--cache-ttl=%d", p.Build.CacheTTL))
 	}
 
+	if p.Build.DigestFile != "" {
+		cmdArgs = append(cmdArgs, fmt.Sprintf("--digest-file=%s", p.Build.DigestFile))
+	}
+
 	cmd := exec.Command("/kaniko/executor", cmdArgs...)
 	cmd.Stdout = os.Stdout
 	cmd.Stderr = os.Stderr
 	trace(cmd)
 
 	err := cmd.Run()
-	return err
+	if err != nil {
+		return err
+	}
+
+	if p.Build.DigestFile != "" && p.Artifact.ArtifactFile != "" {
+		content, err := ioutil.ReadFile(p.Build.DigestFile)
+		if err != nil {
+			fmt.Fprintf(os.Stderr, "failed to read digest file contents at path: %s with error: %s\n", p.Build.DigestFile, err)
+		}
+		err = artifact.WritePluginArtifactFile(p.Artifact.RegistryType, p.Artifact.ArtifactFile, p.Artifact.Registry, p.Artifact.Repo, string(content), p.Artifact.Tags)
+		if err != nil {
+			fmt.Fprintf(os.Stderr, "failed to write plugin artifact file at path: %s with error: %s\n", p.Artifact.ArtifactFile, err)
+		}
+	}
+
+	return nil
 }
 
 // trace writes each command to stdout with the command wrapped in an xml