fix: search $DOCKER_CONFIG if no base64 config is provided

envbuilder.go

@@ -154,13 +154,13 @@ func run(ctx context.Context, opts options.Options, execArgs *execArgsInfo) erro
 
 	opts.Logger(log.LevelInfo, "%s %s - Build development environments from repositories in a container", newColor(color.Bold).Sprintf("envbuilder"), buildinfo.Version())
 
-	cleanupDockerConfigJSON, err := initDockerConfigJSON(opts.Logger, workingDir, opts.DockerConfigBase64)
+	cleanupDockerConfigOverride, err := initDockerConfigOverride(opts.Logger, workingDir, opts.DockerConfigBase64)
 	if err != nil {
 		return err
 	}
 	defer func() {
-		if err := cleanupDockerConfigJSON(); err != nil {
-			opts.Logger(log.LevelError, "failed to cleanup docker config JSON: %w", err)
+		if err := cleanupDockerConfigOverride(); err != nil {
+			opts.Logger(log.LevelError, "failed to cleanup docker config override: %w", err)
 		}
 	}() // best effort
 
@@ -771,7 +771,7 @@ func run(ctx context.Context, opts options.Options, execArgs *execArgsInfo) erro
 	}
 
 	// Remove the Docker config secret file!
-	if err := cleanupDockerConfigJSON(); err != nil {
+	if err := cleanupDockerConfigOverride(); err != nil {
 		return err
 	}
 
@@ -978,13 +978,13 @@ func RunCacheProbe(ctx context.Context, opts options.Options) (v1.Image, error)
 
 	opts.Logger(log.LevelInfo, "%s %s - Build development environments from repositories in a container", newColor(color.Bold).Sprintf("envbuilder"), buildinfo.Version())
 
-	cleanupDockerConfigJSON, err := initDockerConfigJSON(opts.Logger, workingDir, opts.DockerConfigBase64)
+	cleanupDockerConfigOverride, err := initDockerConfigOverride(opts.Logger, workingDir, opts.DockerConfigBase64)
 	if err != nil {
 		return nil, err
 	}
 	defer func() {
-		if err := cleanupDockerConfigJSON(); err != nil {
-			opts.Logger(log.LevelError, "failed to cleanup docker config JSON: %w", err)
+		if err := cleanupDockerConfigOverride(); err != nil {
+			opts.Logger(log.LevelError, "failed to cleanup docker config override: %w", err)
 		}
 	}() // best effort
 
@@ -1315,7 +1315,7 @@ func RunCacheProbe(ctx context.Context, opts options.Options) (v1.Image, error)
 	options.UnsetEnv()
 
 	// Remove the Docker config secret file!
-	if err := cleanupDockerConfigJSON(); err != nil {
+	if err := cleanupDockerConfigOverride(); err != nil {
 		return nil, err
 	}
 
@@ -1627,55 +1627,83 @@ func parseMagicImageFile(fs billy.Filesystem, path string, v any) error {
 	return nil
 }
 
-func initDockerConfigJSON(logf log.Func, workingDir workingdir.WorkingDir, dockerConfigBase64 string) (func() error, error) {
-	var cleanupOnce sync.Once
-	noop := func() error { return nil }
+func initDockerConfigOverride(logf log.Func, workingDir workingdir.WorkingDir, dockerConfigBase64 string) (func() error, error) {
+	var (
+		oldDockerConfig = os.Getenv("DOCKER_CONFIG")
+		newDockerConfig = workingDir.Path()
+		cfgPath         = workingDir.Join("config.json")
+		restoreEnv      = func() error { return nil } // noop.
+	)
+	if dockerConfigBase64 != "" || oldDockerConfig == "" {
+		err := os.Setenv("DOCKER_CONFIG", newDockerConfig)
+		if err != nil {
+			logf(log.LevelError, "Failed to set DOCKER_CONFIG: %s", err)
+			return nil, fmt.Errorf("set DOCKER_CONFIG: %w", err)
+		}
+		logf(log.LevelInfo, "Set DOCKER_CONFIG to %s", newDockerConfig)
+
+		restoreEnv = func() error {
+			// Restore the old DOCKER_CONFIG value.
+			if oldDockerConfig == "" {
+				err := os.Unsetenv("DOCKER_CONFIG")
+				if err != nil {
+					err = fmt.Errorf("unset DOCKER_CONFIG: %w", err)
+				}
+				return err
+			}
+			err := os.Setenv("DOCKER_CONFIG", oldDockerConfig)
+			if err != nil {
+				return fmt.Errorf("restore DOCKER_CONFIG: %w", err)
+			}
+			logf(log.LevelInfo, "Restored DOCKER_CONFIG to %s", oldDockerConfig)
+			return nil
+		}
+	} else {
+		logf(log.LevelInfo, "Using existing DOCKER_CONFIG set to %s", oldDockerConfig)
+	}
+
 	if dockerConfigBase64 == "" {
-		return noop, nil
+		return restoreEnv, nil
 	}
-	cfgPath := workingDir.Join("config.json")
+
 	decoded, err := base64.StdEncoding.DecodeString(dockerConfigBase64)
 	if err != nil {
-		return noop, fmt.Errorf("decode docker config: %w", err)
+		return restoreEnv, fmt.Errorf("decode docker config: %w", err)
 	}
 	var configFile DockerConfig
 	decoded, err = hujson.Standardize(decoded)
 	if err != nil {
-		return noop, fmt.Errorf("humanize json for docker config: %w", err)
+		return restoreEnv, fmt.Errorf("humanize json for docker config: %w", err)
 	}
 	err = json.Unmarshal(decoded, &configFile)
 	if err != nil {
-		return noop, fmt.Errorf("parse docker config: %w", err)
+		return restoreEnv, fmt.Errorf("parse docker config: %w", err)
 	}
 	for k := range configFile.AuthConfigs {
 		logf(log.LevelInfo, "Docker config contains auth for registry %q", k)
 	}
 	err = os.WriteFile(cfgPath, decoded, 0o644)
 	if err != nil {
-		return noop, fmt.Errorf("write docker config: %w", err)
+		return restoreEnv, fmt.Errorf("write docker config: %w", err)
 	}
 	logf(log.LevelInfo, "Wrote Docker config JSON to %s", cfgPath)
-	oldDockerConfig := os.Getenv("DOCKER_CONFIG")
-	_ = os.Setenv("DOCKER_CONFIG", workingDir.Path())
-	newDockerConfig := os.Getenv("DOCKER_CONFIG")
-	logf(log.LevelInfo, "Set DOCKER_CONFIG to %s", newDockerConfig)
-	cleanup := func() error {
+
+	var cleanupOnce sync.Once
+	return func() error {
 		var cleanupErr error
 		cleanupOnce.Do(func() {
-			// Restore the old DOCKER_CONFIG value.
-			os.Setenv("DOCKER_CONFIG", oldDockerConfig)
-			logf(log.LevelInfo, "Restored DOCKER_CONFIG to %s", oldDockerConfig)
+			cleanupErr = restoreEnv()
 			// Remove the Docker config secret file!
-			if cleanupErr = os.Remove(cfgPath); err != nil {
+			if err := os.Remove(cfgPath); err != nil {
 				if !errors.Is(err, fs.ErrNotExist) {
-					cleanupErr = fmt.Errorf("remove docker config: %w", cleanupErr)
+					err = errors.Join(err, fmt.Errorf("remove docker config: %w", err))
 				}
 				logf(log.LevelError, "Failed to remove the Docker config secret file: %s", cleanupErr)
+				cleanupErr = errors.Join(cleanupErr, err)
 			}
 		})
 		return cleanupErr
-	}
-	return cleanup, err
+	}, nil
 }
 
 // Allows quick testing of layer caching using a local directory!

integration/integration_test.go

@@ -552,13 +552,20 @@ func TestBuildFromDockerfile(t *testing.T) {
 			"Dockerfile": "FROM " + testImageAlpine,
 		},
 	})
-	ctr, err := runEnvbuilder(t, runOpts{env: []string{
-		envbuilderEnv("GIT_URL", srv.URL),
-		envbuilderEnv("DOCKERFILE_PATH", "Dockerfile"),
-		envbuilderEnv("DOCKER_CONFIG_BASE64", base64.StdEncoding.EncodeToString([]byte(`{"experimental": "enabled"}`))),
-	}})
+	logbuf := new(bytes.Buffer)
+	ctr, err := runEnvbuilder(t, runOpts{
+		env: []string{
+			envbuilderEnv("GIT_URL", srv.URL),
+			envbuilderEnv("DOCKERFILE_PATH", "Dockerfile"),
+			envbuilderEnv("DOCKER_CONFIG_BASE64", base64.StdEncoding.EncodeToString([]byte(`{"experimental": "enabled"}`))),
+			"DOCKER_CONFIG=/config", // Ignored, because we're setting DOCKER_CONFIG_BASE64.
+		},
+		logbuf: logbuf,
+	})
 	require.NoError(t, err)
 
+	require.Contains(t, logbuf.String(), "Set DOCKER_CONFIG to /.envbuilder")
+
 	output := execContainer(t, ctr, "echo hello")
 	require.Equal(t, "hello", strings.TrimSpace(output))
 
@@ -568,6 +575,52 @@ func TestBuildFromDockerfile(t *testing.T) {
 	require.Contains(t, output, "No such file or directory")
 }
 
+func TestBuildDockerConfigPathFromEnv(t *testing.T) {
+	// Ensures that a Git repository with a Dockerfile is cloned and built.
+	srv := gittest.CreateGitServer(t, gittest.Options{
+		Files: map[string]string{
+			"Dockerfile": "FROM " + testImageAlpine,
+		},
+	})
+	dir := t.TempDir()
+	err := os.WriteFile(filepath.Join(dir, "config.json"), []byte(`{"experimental": "enabled"}`), 0o644)
+	require.NoError(t, err)
+
+	logbuf := new(bytes.Buffer)
+	_, err = runEnvbuilder(t, runOpts{
+		env: []string{
+			envbuilderEnv("GIT_URL", srv.URL),
+			envbuilderEnv("DOCKERFILE_PATH", "Dockerfile"),
+			"DOCKER_CONFIG=/config",
+		},
+		binds:  []string{fmt.Sprintf("%s:/config:ro", dir)},
+		logbuf: logbuf,
+	})
+	require.NoError(t, err)
+
+	require.Contains(t, logbuf.String(), "Using existing DOCKER_CONFIG set to /config")
+}
+
+func TestBuildDockerConfigDefaultPath(t *testing.T) {
+	// Ensures that a Git repository with a Dockerfile is cloned and built.
+	srv := gittest.CreateGitServer(t, gittest.Options{
+		Files: map[string]string{
+			"Dockerfile": "FROM " + testImageAlpine,
+		},
+	})
+	logbuf := new(bytes.Buffer)
+	_, err := runEnvbuilder(t, runOpts{
+		env: []string{
+			envbuilderEnv("GIT_URL", srv.URL),
+			envbuilderEnv("DOCKERFILE_PATH", "Dockerfile"),
+		},
+		logbuf: logbuf,
+	})
+	require.NoError(t, err)
+
+	require.Contains(t, logbuf.String(), "Set DOCKER_CONFIG to /.envbuilder")
+}
+
 func TestBuildPrintBuildOutput(t *testing.T) {
 	// Ensures that a Git repository with a Dockerfile is cloned and built.
 	srv := gittest.CreateGitServer(t, gittest.Options{
@@ -2296,6 +2349,7 @@ type runOpts struct {
 	binds   []string
 	env     []string
 	volumes map[string]string
+	logbuf  *bytes.Buffer
 }
 
 // runEnvbuilder starts the envbuilder container with the given environment
@@ -2340,6 +2394,7 @@ func runEnvbuilder(t *testing.T, opts runOpts) (string, error) {
 			testContainerLabel: "true",
 		},
 	}, &container.HostConfig{
+		CapAdd:      []string{"SYS_ADMIN"}, // For remounting.
 		NetworkMode: container.NetworkMode("host"),
 		Binds:       opts.binds,
 		Mounts:      mounts,
@@ -2357,6 +2412,9 @@ func runEnvbuilder(t *testing.T, opts runOpts) (string, error) {
 	logChan, errChan := streamContainerLogs(t, cli, ctr.ID)
 	go func() {
 		for log := range logChan {
+			if opts.logbuf != nil {
+				opts.logbuf.WriteString(log)
+			}
 			if strings.HasPrefix(log, "=== Running init command") {
 				errChan <- nil
 				return