Add support for secrets in composefiles

Signed-off-by: Jean-Christophe Sirot <[email protected]>

Author: Jean-Christophe Sirot

internal/names.go

@@ -45,6 +45,10 @@ const (
 	CredentialRegistryName = Namespace + "registry-creds"
 	// CredentialRegistryPath is the name to the credential containing registry credentials
 	CredentialRegistryPath = "/cnab/app/registry-creds.json"
+	// SecretsPath is the directory where secret files are mounted
+	SecretsPath = "/cnab/app/secrets"
+	// SecretsParameterPrefix is the prefix used by WriteOnly parameters
+	SecretsParameterPrefix = Namespace + "secret."
 
 	// ParameterOrchestratorName is the name of the parameter containing the orchestrator
 	ParameterOrchestratorName = Namespace + "orchestrator"

internal/packager/cnab.go

@@ -108,6 +108,20 @@ func ToCNAB(app *types.App, invocationImageName string) (*bundle.Bundle, error)
 			Definition: name,
 		}
 	}
+	for name, secret := range app.Secrets() {
+		writeOnly := new(bool)
+		*writeOnly = true
+		definitions[internal.SecretsParameterPrefix+name] = &definition.Schema{
+			Type:      "string",
+			WriteOnly: writeOnly,
+		}
+		parameters[internal.SecretsParameterPrefix+name] = bundle.Parameter{
+			Destination: &bundle.Location{
+				Path: secret.NormalizeFilename(),
+			},
+			Definition: internal.SecretsParameterPrefix + name,
+		}
+	}
 	var maintainers []bundle.Maintainer
 	for _, m := range app.Metadata().Maintainers {
 		maintainers = append(maintainers, bundle.Maintainer{

types/secrets/secrets.go

@@ -0,0 +1,27 @@
+package secrets
+
+import (
+	"crypto/sha256"
+	"fmt"
+)
+
+// Secrets represents a secret map
+type Secrets map[string]Secret
+
+// Secret represents a secret
+type Secret struct {
+	Path     string
+	External bool
+	Name     string
+}
+
+// New creates a new empty secret map
+func New() Secrets {
+	return make(map[string]Secret)
+}
+
+// NormalizeFilename generates a filename for this secret to be mounted in the invocation image
+func (s *Secret) NormalizeFilename() string {
+	digest := sha256.Sum256([]byte(s.Path))
+	return fmt.Sprintf("/cnab/app/secret/%x", digest)
+}

types/types.go

@@ -9,9 +9,13 @@ import (
 	"path/filepath"
 	"strings"
 
+	composeloader "github.com/docker/cli/cli/compose/loader"
+	composetypes "github.com/docker/cli/cli/compose/types"
+
 	"github.com/docker/app/internal"
 	"github.com/docker/app/types/metadata"
 	"github.com/docker/app/types/parameters"
+	"github.com/docker/app/types/secrets"
 )
 
 // AppSourceKind represents what format the app was in when read
@@ -41,6 +45,7 @@ type App struct {
 	composesContent   [][]byte
 	parametersContent [][]byte
 	parameters        parameters.Parameters
+	secrets           secrets.Secrets
 	metadataContent   []byte
 	metadata          metadata.AppMetadata
 	attachments       []Attachment
@@ -93,6 +98,11 @@ func (a *App) Attachments() []Attachment {
 	return a.attachments
 }
 
+// Secrets returns a map of secrets
+func (a *App) Secrets() secrets.Secrets {
+	return a.secrets
+}
+
 func (a *App) HasCRLF() bool {
 	return a.hasCRLF
 }
@@ -288,10 +298,36 @@ func composeLoader(f func() ([][]byte, error)) func(app *App) error {
 			return err
 		}
 		app.composesContent = append(app.composesContent, composesContent...)
+		app.secrets = secrets.New()
+		for _, c := range app.composesContent {
+			parsedCompose, err := composeloader.ParseYAML(c)
+			if err != nil {
+				return err
+			}
+			cfg, err := composeloader.Load(composetypes.ConfigDetails{
+				ConfigFiles: []composetypes.ConfigFile{
+					{Filename: "docker-compose.yml", Config: parsedCompose},
+				},
+			}, withSkipInterpolation)
+			if err != nil {
+				return err
+			}
+			for name, secret := range cfg.Secrets {
+				app.secrets[name] = secrets.Secret{
+					Name:     secret.Name,
+					Path:     secret.File,
+					External: secret.External.External,
+				}
+			}
+		}
 		return nil
 	}
 }
 
+func withSkipInterpolation(opts *composeloader.Options) {
+	opts.SkipInterpolation = true
+}
+
 func readReaders(readers ...io.Reader) ([][]byte, error) {
 	content := make([][]byte, len(readers))
 	var errs []string