Add support for stateless actions (#630)

This implements stateless actions as defined in cnabio/cnab-spec#85.

pkg/action/action.go

@@ -13,6 +13,9 @@ import (
 	"github.com/deislabs/duffle/pkg/driver"
 )
 
+// notStateless is there just to make callers of opFromClaims more readable
+const notStateless = false
+
 // Action describes one of the primary actions that can be executed in CNAB.
 //
 // The actions are:
@@ -48,8 +51,8 @@ func getImageMap(b *bundle.Bundle) ([]byte, error) {
 	return json.Marshal(imgs)
 }
 
-func opFromClaim(action string, c *claim.Claim, ii bundle.InvocationImage, creds credentials.Set, w io.Writer) (*driver.Operation, error) {
-	env, files, err := creds.Expand(c.Bundle)
+func opFromClaim(action string, stateless bool, c *claim.Claim, ii bundle.InvocationImage, creds credentials.Set, w io.Writer) (*driver.Operation, error) {
+	env, files, err := creds.Expand(c.Bundle, stateless)
 	if err != nil {
 		return nil, err
 	}

pkg/action/action_test.go

@@ -99,7 +99,7 @@ func TestOpFromClaim(t *testing.T) {
 	}
 	invocImage := c.Bundle.InvocationImages[0]
 
-	op, err := opFromClaim(claim.ActionInstall, c, invocImage, mockSet, os.Stdout)
+	op, err := opFromClaim(claim.ActionInstall, notStateless, c, invocImage, mockSet, os.Stdout)
 	if err != nil {
 		t.Fatal(err)
 	}
@@ -140,7 +140,7 @@ func TestOpFromClaim_UndefinedParams(t *testing.T) {
 	}
 	invocImage := c.Bundle.InvocationImages[0]
 
-	_, err := opFromClaim(claim.ActionInstall, c, invocImage, mockSet, os.Stdout)
+	_, err := opFromClaim(claim.ActionInstall, notStateless, c, invocImage, mockSet, os.Stdout)
 	assert.Error(t, err)
 }
 

pkg/action/install.go

@@ -20,7 +20,7 @@ func (i *Install) Run(c *claim.Claim, creds credentials.Set, w io.Writer) error
 		return err
 	}
 
-	op, err := opFromClaim(claim.ActionInstall, c, invocImage, creds, w)
+	op, err := opFromClaim(claim.ActionInstall, notStateless, c, invocImage, creds, w)
 	if err != nil {
 		return err
 	}

pkg/action/run_custom.go

@@ -43,7 +43,7 @@ func (i *RunCustom) Run(c *claim.Claim, creds credentials.Set, w io.Writer) erro
 		return err
 	}
 
-	op, err := opFromClaim(i.Action, c, invocImage, creds, w)
+	op, err := opFromClaim(i.Action, actionDef.Stateless, c, invocImage, creds, w)
 	if err != nil {
 		return err
 	}

pkg/action/status.go

@@ -20,7 +20,7 @@ func (i *Status) Run(c *claim.Claim, creds credentials.Set, w io.Writer) error {
 		return err
 	}
 
-	op, err := opFromClaim(claim.ActionStatus, c, invocImage, creds, w)
+	op, err := opFromClaim(claim.ActionStatus, notStateless, c, invocImage, creds, w)
 	if err != nil {
 		return err
 	}

pkg/action/uninstall.go

@@ -20,7 +20,7 @@ func (u *Uninstall) Run(c *claim.Claim, creds credentials.Set, w io.Writer) erro
 		return err
 	}
 
-	op, err := opFromClaim(claim.ActionUninstall, c, invocImage, creds, w)
+	op, err := opFromClaim(claim.ActionUninstall, notStateless, c, invocImage, creds, w)
 	if err != nil {
 		return err
 	}

pkg/action/upgrade.go

@@ -20,7 +20,7 @@ func (u *Upgrade) Run(c *claim.Claim, creds credentials.Set, w io.Writer) error
 		return err
 	}
 
-	op, err := opFromClaim(claim.ActionUpgrade, c, invocImage, creds, w)
+	op, err := opFromClaim(claim.ActionUpgrade, notStateless, c, invocImage, creds, w)
 	if err != nil {
 		return err
 	}

pkg/bundle/bundle.go

@@ -118,6 +118,10 @@ type Action struct {
 	//
 	// If it is possible that an action modify a release, this must be set to true.
 	Modifies bool `json:"modifies" mapstructure:"modifies"`
+	// Stateless indicates that the action is purely informational, that credentials are not required, and that the runtime should not keep track of its invocation
+	Stateless bool `json:"stateless,omitempty" mapstructure:"stateless"`
+	// Description describes the action as a user-readable string
+	Description string `json:"description,omitempty" mapstructure:"description,omitempty"`
 }
 
 // ValuesOrDefaults returns parameter values or the default parameter values

pkg/credentials/credentialset.go

@@ -20,11 +20,14 @@ type Set map[string]string
 //
 // This matches the credentials required by the bundle to the credentials present
 // in the credentialset, and then expands them per the definition in the Bundle.
-func (s Set) Expand(b *bundle.Bundle) (env, files map[string]string, err error) {
+func (s Set) Expand(b *bundle.Bundle, stateless bool) (env, files map[string]string, err error) {
 	env, files = map[string]string{}, map[string]string{}
 	for name, val := range b.Credentials {
 		src, ok := s[name]
 		if !ok {
+			if stateless {
+				continue
+			}
 			err = fmt.Errorf("credential %q is missing from the user-supplied credentials", name)
 			return
 		}

pkg/credentials/credentialset_test.go

@@ -73,7 +73,7 @@ func TestCredentialSet_Expand(t *testing.T) {
 		"third":  "third",
 	}
 
-	env, path, err := cs.Expand(b)
+	env, path, err := cs.Expand(b, false)
 	is := assert.New(t)
 	is.NoError(err)
 	for k, v := range b.Credentials {
@@ -85,3 +85,19 @@ func TestCredentialSet_Expand(t *testing.T) {
 		}
 	}
 }
+
+func TestCredentialSetMissingCred(t *testing.T) {
+	b := &bundle.Bundle{
+		Name: "knapsack",
+		Credentials: map[string]bundle.Location{
+			"first": {
+				EnvironmentVariable: "FIRST_VAR",
+			},
+		},
+	}
+	cs := Set{}
+	_, _, err := cs.Expand(b, false)
+	assert.EqualError(t, err, `credential "first" is missing from the user-supplied credentials`)
+	_, _, err = cs.Expand(b, true)
+	assert.NoError(t, err)
+}