Add GCP snapshot volume support to kanister (#4788)

* copy k10/blockstorage/gcepd to kansiter

* Modify blockstorage for GCP Volume snapshot

* remove kasten reference

* Use poll.Wait() instead of time.Sleep()

* Fix space b/w comments & serviceKey assignment

* nit fix

* set label in initial CreateSnapshot() call

pkg/blockstorage/blockstorage_test.go

@@ -31,23 +31,11 @@ type BlockStorageProviderSuite struct {
 }
 
 var _ = Suite(&BlockStorageProviderSuite{storageType: blockstorage.TypeEBS, storageRegion: clusterRegionAWS})
+var _ = Suite(&BlockStorageProviderSuite{storageType: blockstorage.TypeGPD, storageRegion: ""})
 
 func (s *BlockStorageProviderSuite) SetUpSuite(c *C) {
-	config := make(map[string]string)
 	var err error
-	if s.storageType == blockstorage.TypeEBS {
-		config[awsebs.ConfigRegion] = s.storageRegion
-		accessKey, ok := os.LookupEnv(awsebs.AccessKeyID)
-		if !ok {
-			c.Skip("The necessary env variable AWS_ACCESS_KEY_ID is not set.")
-		}
-		secretAccessKey, ok := os.LookupEnv(awsebs.SecretAccessKey)
-		if !ok {
-			c.Skip("The necessary env variable AWS_SECRET_ACCESS_KEY is not set.")
-		}
-		config[awsebs.AccessKeyID] = accessKey
-		config[awsebs.SecretAccessKey] = secretAccessKey
-	}
+	config := s.getConfig(c, s.storageRegion)
 	s.provider, err = getter.New().Get(s.storageType, config)
 	c.Assert(err, IsNil)
 }
@@ -147,16 +135,7 @@ func (s *BlockStorageProviderSuite) TestSnapshotCopy(c *C) {
 
 	log.Infof("Copied snapshot %v to %v", srcSnapshot.ID, snap.ID)
 
-	config := make(map[string]string)
-	if s.storageType == blockstorage.TypeEBS {
-		config[awsebs.ConfigRegion] = dstSnapshot.Region
-		accessKey := os.Getenv(awsebs.AccessKeyID)
-		c.Assert(len(accessKey) > 0, Equals, true)
-		secretAccessKey := os.Getenv(awsebs.SecretAccessKey)
-		c.Assert(len(secretAccessKey) > 0, Equals, true)
-		config[awsebs.AccessKeyID] = accessKey
-		config[awsebs.SecretAccessKey] = secretAccessKey
-	}
+	config := s.getConfig(c, dstSnapshot.Region)
 	provider, err := getter.New().Get(s.storageType, config)
 	c.Assert(err, IsNil)
 
@@ -267,3 +246,28 @@ func (s *BlockStorageProviderSuite) checkStdTagsExist(c *C, actual map[string]st
 		c.Check(actual[k], NotNil)
 	}
 }
+
+func (s *BlockStorageProviderSuite) getConfig(c *C, region string) map[string]string {
+	config := make(map[string]string)
+	switch s.storageType {
+	case blockstorage.TypeEBS:
+		config[awsebs.ConfigRegion] = region
+		accessKey, ok := os.LookupEnv(awsebs.AccessKeyID)
+		if !ok {
+			c.Skip("The necessary env variable AWS_ACCESS_KEY_ID is not set.")
+		}
+		secretAccessKey, ok := os.LookupEnv(awsebs.SecretAccessKey)
+		if !ok {
+			c.Skip("The necessary env variable AWS_SECRET_ACCESS_KEY is not set.")
+		}
+		config[awsebs.AccessKeyID] = accessKey
+		config[awsebs.SecretAccessKey] = secretAccessKey
+	case blockstorage.TypeGPD:
+		creds, ok := os.LookupEnv(blockstorage.GoogleCloudCreds)
+		if !ok {
+			c.Skip("The necessary env variable GOOGLE_APPLICATION_CREDENTIALS is not set.")
+		}
+		config[blockstorage.GoogleCloudCreds] = creds
+	}
+	return config
+}

pkg/blockstorage/gcepd/client.go

@@ -0,0 +1,49 @@
+package gcepd
+
+import (
+	"context"
+	"net/http"
+
+	"golang.org/x/oauth2"
+	"golang.org/x/oauth2/google"
+	compute "google.golang.org/api/compute/v1"
+)
+
+// Client is a wrapper for Client client
+type Client struct {
+	Service   *compute.Service
+	ProjectID string
+}
+
+// NewClient returns a Client struct
+func NewClient(ctx context.Context, servicekey string) (*Client, error) {
+	var err error
+	var creds *google.Credentials
+	if len(servicekey) > 0 {
+		creds, err = google.CredentialsFromJSON(ctx, []byte(servicekey), compute.ComputeScope)
+	} else {
+		creds, err = google.FindDefaultCredentials(ctx, compute.ComputeScope)
+	}
+
+	if err != nil {
+		return nil, err
+	}
+	// NOTE: Ashlie is not sure how long this will work for since a comment at
+	// https://godoc.org/golang.org/x/oauth2#NewClient
+	// states that the client in the context will only be used for getting a
+	// token.
+	httpClient := &http.Client{Transport: http.DefaultTransport}
+	ctx = context.WithValue(ctx, oauth2.HTTPClient, httpClient)
+
+	client := oauth2.NewClient(ctx, creds.TokenSource)
+
+	service, err := compute.New(client)
+	if err != nil {
+		return nil, err
+	}
+
+	return &Client{
+		Service:   service,
+		ProjectID: creds.ProjectID,
+	}, nil
+}

pkg/blockstorage/gcepd/client_test.go

@@ -0,0 +1,45 @@
+package gcepd
+
+import (
+	"context"
+	"io/ioutil"
+	"os"
+	"testing"
+
+	. "gopkg.in/check.v1"
+
+	"github.com/kanisterio/kanister/pkg/blockstorage"
+)
+
+// Hook up gocheck into the "go test" runner.
+func Test(t *testing.T) { TestingT(t) }
+
+type ClientSuite struct{}
+
+var _ = Suite(&ClientSuite{})
+
+func (s *ClientSuite) SetUpSuite(c *C) {}
+
+func (s *ClientSuite) TestClient(c *C) {
+	var zone string
+	filename := s.GetEnvOrSkip(c, blockstorage.GoogleCloudCreds)
+	b, err := ioutil.ReadFile(filename)
+	c.Assert(err, IsNil)
+	gCli, err := NewClient(context.Background(), string(b))
+	c.Assert(err, IsNil)
+	c.Assert(gCli.Service, NotNil)
+	c.Assert(*gCli, FitsTypeOf, Client{})
+	// Get zone
+	zone = s.GetEnvOrSkip(c, blockstorage.GoogleCloudZone)
+	_, err = gCli.Service.Disks.List(gCli.ProjectID, zone).Do()
+	c.Assert(err, IsNil)
+}
+
+func (s *ClientSuite) GetEnvOrSkip(c *C, varName string) string {
+	v := os.Getenv(varName)
+	// Ensure the variable is set
+	if v == "" {
+		c.Skip("Required environment variable " + varName + " is not set")
+	}
+	return v
+}