Add remove function to context store

Signed-off-by: Christopher Crone <christopher.crone@docker.com>

context/store/store.go

@@ -30,6 +30,7 @@ package store
 import (
 	"context"
 	"encoding/json"
+	"fmt"
 	"io/ioutil"
 	"os"
 	"path/filepath"
@@ -71,6 +72,8 @@ type Store interface {
 	Create(name string, data TypedContext) error
 	// List returns the list of created contexts
 	List() ([]*Metadata, error)
+	// Remove removes a context by name from the context store
+	Remove(name string) error
 }
 
 type store struct {
@@ -119,7 +122,7 @@ func (s *store) Get(name string, getter func() interface{}) (*Metadata, error) {
 	meta := filepath.Join(s.root, contextsDir, metadataDir, contextdirOf(name), metaFile)
 	m, err := read(meta, getter)
 	if os.IsNotExist(err) {
-		return nil, errors.Wrapf(errdefs.ErrNotFound, "context %q", name)
+		return nil, errors.Wrap(errdefs.ErrNotFound, objectName(name))
 	} else if err != nil {
 		return nil, err
 	}
@@ -187,7 +190,7 @@ func (s *store) Create(name string, data TypedContext) error {
 	dir := contextdirOf(name)
 	metaDir := filepath.Join(s.root, contextsDir, metadataDir, dir)
 	if _, err := os.Stat(metaDir); !os.IsNotExist(err) {
-		return errors.Wrapf(errdefs.ErrAlreadyExists, "context %q", name)
+		return errors.Wrap(errdefs.ErrAlreadyExists, objectName(name))
 	}
 
 	err := os.Mkdir(metaDir, 0755)
@@ -238,10 +241,26 @@ func (s *store) List() ([]*Metadata, error) {
 	return result, nil
 }
 
+func (s *store) Remove(name string) error {
+	dir := filepath.Join(s.root, contextsDir, metadataDir, contextdirOf(name))
+	// Check if directory exists because os.RemoveAll returns nil if it doesn't
+	if _, err := os.Stat(dir); os.IsNotExist(err) {
+		return errors.Wrap(errdefs.ErrNotFound, objectName(name))
+	}
+	if err := os.RemoveAll(dir); err != nil {
+		return errors.Wrapf(errdefs.ErrUnknown, "unable to remove %s: %s", objectName(name), err)
+	}
+	return nil
+}
+
 func contextdirOf(name string) string {
 	return digest.FromString(name).Encoded()
 }
 
+func objectName(name string) string {
+	return fmt.Sprintf("context %q", name)
+}
+
 type dummyContext struct{}
 
 // Metadata represents the docker context metadata

context/store/store_test.go

@@ -107,6 +107,26 @@ func (suite *StoreTestSuite) TestList() {
 	require.Equal(suite.T(), contexts[1].Name, "test2")
 }
 
+func (suite *StoreTestSuite) TestRemoveNotFound() {
+	err := suite.store.Remove("notfound")
+	require.EqualError(suite.T(), err, `context "notfound": not found`)
+	require.True(suite.T(), errdefs.IsNotFoundError(err))
+}
+
+func (suite *StoreTestSuite) TestRemove() {
+	err := suite.store.Create("testremove", TypedContext{})
+	require.Nil(suite.T(), err)
+	contexts, err := suite.store.List()
+	require.Nil(suite.T(), err)
+	require.Equal(suite.T(), len(contexts), 1)
+
+	err = suite.store.Remove("testremove")
+	require.Nil(suite.T(), err)
+	contexts, err = suite.store.List()
+	require.Nil(suite.T(), err)
+	require.Equal(suite.T(), len(contexts), 0)
+}
+
 func TestExampleTestSuite(t *testing.T) {
 	suite.Run(t, new(StoreTestSuite))
 }