Transform render command as a CNAB custom action, running in the invocation image as a stateless action.

Adding a new custom parameter "com.docker.app.render-format" used only by the render action.

Signed-off-by: Silvin Lubecki <silvin.lubecki@docker.com>

Author: silvin-lubecki

cmd/cnab-run/main.go

@@ -17,6 +17,7 @@ var (
 		"uninstall":                    uninstallAction,
 		internal.Namespace + "status":  statusAction,
 		internal.Namespace + "inspect": inspectAction,
+		internal.Namespace + "render":  renderAction,
 	}
 )
 

cmd/cnab-run/render.go

@@ -0,0 +1,45 @@
+package main
+
+import (
+	"fmt"
+	"os"
+
+	"github.com/docker/app/internal"
+
+	"github.com/docker/app/internal/formatter"
+	"github.com/docker/app/internal/packager"
+	"github.com/docker/app/render"
+)
+
+func renderAction(instanceName string) error {
+	app, err := packager.Extract("")
+	// todo: merge additional compose file
+	if err != nil {
+		return err
+	}
+	defer app.Cleanup()
+
+	imageMap, err := getBundleImageMap()
+	if err != nil {
+		return err
+	}
+
+	formatDriver, ok := os.LookupEnv(internal.DockerRenderFormatEnvVar)
+	if !ok {
+		return fmt.Errorf("%q is undefined", internal.DockerRenderFormatEnvVar)
+	}
+
+	parameters := packager.ExtractCNABParametersValues(packager.ExtractCNABParameterMapping(app.Parameters()), os.Environ())
+
+	rendered, err := render.Render(app, parameters, imageMap)
+	if err != nil {
+		return err
+	}
+	res, err := formatter.Format(rendered, formatDriver)
+	if err != nil {
+		return err
+	}
+	fmt.Printf(res)
+
+	return nil
+}

e2e/testdata/simple-bundle.json.golden

@@ -49,6 +49,10 @@
 			"modifies": false,
 			"stateless": true
 		},
+		"com.docker.app.render": {
+			"modifies": false,
+			"stateless": true
+		},
 		"com.docker.app.status": {
 			"modifies": false
 		}
@@ -105,6 +109,25 @@
 				"com.docker.app.status"
 			]
 		},
+		"com.docker.app.render-format": {
+			"type": "string",
+			"defaultValue": "yaml",
+			"allowedValues": [
+				"yaml",
+				"json"
+			],
+			"required": false,
+			"metadata": {
+				"description": "Output format for the render command"
+			},
+			"destination": {
+				"path": "",
+				"env": "DOCKER_RENDER_FORMAT"
+			},
+			"apply-to": [
+				"com.docker.app.render"
+			]
+		},
 		"static_subdir": {
 			"type": "string",
 			"defaultValue": "data/static",

internal/commands/render.go

@@ -1,74 +1,88 @@
 package commands
 
 import (
-	"fmt"
+	"io"
 	"os"
 
+	"github.com/deislabs/duffle/pkg/action"
+	"github.com/deislabs/duffle/pkg/claim"
 	"github.com/docker/app/internal"
-	"github.com/docker/app/internal/formatter"
-	"github.com/docker/app/internal/packager"
-	"github.com/docker/app/render"
-	"github.com/docker/app/types"
 	"github.com/docker/cli/cli"
 	"github.com/docker/cli/cli/command"
-	cliopts "github.com/docker/cli/opts"
+	"github.com/pkg/errors"
 	"github.com/spf13/cobra"
 )
 
-var (
-	formatDriver         string
-	renderComposeFiles   []string
-	renderParametersFile []string
-	renderEnv            []string
-	renderOutput         string
-)
+type renderOptions struct {
+	parametersOptions
+	registryOptions
+	pullOptions
+
+	formatDriver string
+	renderOutput string
+}
 
 func renderCmd(dockerCli command.Cli) *cobra.Command {
+	var opts renderOptions
 	cmd := &cobra.Command{
 		Use:   "render <app-name> [-s key=value...] [-f parameters-file...]",
 		Short: "Render the Compose file for the application",
 		Long:  `Render the Compose file for the application.`,
 		Args:  cli.RequiresMaxArgs(1),
 		RunE: func(cmd *cobra.Command, args []string) error {
-			app, err := packager.Extract(firstOrEmpty(args),
-				types.WithParametersFiles(renderParametersFile...),
-				types.WithComposeFiles(renderComposeFiles...),
-			)
-			if err != nil {
-				return err
-			}
-			defer app.Cleanup()
-			d := cliopts.ConvertKVStringsToMap(renderEnv)
-			rendered, err := render.Render(app, d, nil)
-			if err != nil {
-				return err
-			}
-			res, err := formatter.Format(rendered, formatDriver)
-			if err != nil {
-				return err
-			}
-			if renderOutput == "-" {
-				fmt.Fprint(dockerCli.Out(), res)
-			} else {
-				f, err := os.Create(renderOutput)
-				if err != nil {
-					return err
-				}
-				fmt.Fprint(f, res)
-			}
-			return nil
+			return runRender(dockerCli, firstOrEmpty(args), opts)
 		},
 	}
-	if internal.Experimental == "on" {
-		cmd.Use += " [-c <compose-files>...]"
-		cmd.Long += `- External Compose files or template Compose files can be specified with the -c flag.
-  (Repeat the flag for multiple files). These files will be merged in order with
-  the app's own Compose file.`
-		cmd.Flags().StringArrayVarP(&renderComposeFiles, "compose-files", "c", []string{}, "Override Compose file")
-	}
-	cmd.Flags().StringArrayVarP(&renderParametersFile, "parameters-files", "f", []string{}, "Override with parameters from files")
-	cmd.Flags().StringArrayVarP(&renderEnv, "set", "s", []string{}, "Override parameters values")
-	cmd.Flags().StringVarP(&renderOutput, "output", "o", "-", "Output file")
-	cmd.Flags().StringVar(&formatDriver, "formatter", "yaml", "Configure the output format (yaml|json)")
+	opts.parametersOptions.addFlags(cmd.Flags())
+	opts.registryOptions.addFlags(cmd.Flags())
+	opts.pullOptions.addFlags(cmd.Flags())
+	cmd.Flags().StringVarP(&opts.renderOutput, "output", "o", "-", "Output file")
+	cmd.Flags().StringVar(&opts.formatDriver, "formatter", "yaml", "Configure the output format (yaml|json)")
+
 	return cmd
 }
+
+func runRender(dockerCli command.Cli, appname string, opts renderOptions) error {
+	defer muteDockerCli(dockerCli)()
+
+	c, err := claim.New("render")
+	if err != nil {
+		return err
+	}
+	driverImpl, err := prepareDriver(dockerCli, bindMount{})
+	if err != nil {
+		return err
+	}
+	bundle, err := resolveBundle(dockerCli, appname, opts.pull, opts.insecureRegistries)
+	if err != nil {
+		return err
+	}
+	c.Bundle = bundle
+
+	parameters, err := mergeBundleParameters(c.Bundle,
+		withFileParameters(opts.parametersFiles),
+		withCommandLineParameters(opts.overrides),
+	)
+	if err != nil {
+		return err
+	}
+	c.Parameters = parameters
+	c.Parameters[internal.Namespace+"render-format"] = opts.formatDriver
+
+	a := &action.RunCustom{
+		Action: internal.Namespace + "render",
+		Driver: driverImpl,
+	}
+
+	var writer io.Writer = dockerCli.Out()
+	if opts.renderOutput != "-" {
+		f, err := os.Create(opts.renderOutput)
+		if err != nil {
+			return err
+		}
+		defer f.Close()
+		writer = f
+	}
+	err = a.Run(c, nil, writer)
+	return errors.Wrap(err, "Render failed")
+}

internal/names.go

@@ -31,6 +31,9 @@ const (
 	// DockerKubernetesNamespaceEnvVar is the environment variable set by the CNAB runtime to select
 	// the kubernetes namespace.
 	DockerKubernetesNamespaceEnvVar = "DOCKER_KUBERNETES_NAMESPACE"
+	// DockerRenderFormatEnvVar is the environment variable set by the CNAB runtime to select
+	// the render output format.
+	DockerRenderFormatEnvVar = "DOCKER_RENDER_FORMAT"
 )
 
 var (

internal/packager/cnab.go

@@ -49,6 +49,22 @@ func ToCNAB(app *types.App, invocationImageName string) (*bundle.Bundle, error)
 				internal.Namespace + "status",
 			},
 		},
+		internal.Namespace + "render-format": {
+			DataType: "string",
+			AllowedValues: []interface{}{
+				"yaml",
+				"json",
+			},
+			DefaultValue: "yaml",
+			Destination: &bundle.Location{
+				EnvironmentVariable: internal.DockerRenderFormatEnvVar,
+			},
+			Metadata: &bundle.ParameterMetadata{
+				Description: "Output format for the render command",
+			},
+			ApplyTo: []string{
+				internal.Namespace + "render",
+			},
 		},
 	}
 	for name, envVar := range mapping.ParameterToCNABEnv {
@@ -97,6 +113,10 @@ func ToCNAB(app *types.App, invocationImageName string) (*bundle.Bundle, error)
 				Modifies:  false,
 				Stateless: true,
 			},
+			internal.Namespace + "render": {
+				Modifies:  false,
+				Stateless: true,
+			},
 			internal.Namespace + "status": {
 				Modifies: false,
 			},