GCP: add optional 'project' config to volume snapshot location

Signed-off-by: Steve Kriss <krisss@vmware.com>

changelogs/unreleased/1405-skriss

@@ -0,0 +1 @@
+GCP: add optional 'project' config to volume snapshot location for if snapshots are in a different project than the IAM account

docs/api-types/volumesnapshotlocation.md

@@ -57,6 +57,7 @@ The configurable parameters are as follows:
 | Key | Type | Default | Meaning |
 | --- | --- | --- | --- |
 | `snapshotLocation` | string | Empty | *Example*: "us-central1"<br><br>See [GCP documentation][4] for the full list.<br><br>If not specified the snapshots are stored in the [default location][5]. |
+| `project` | string | Empty | The project ID where snapshots should be stored, if different than the project that your IAM account is in. Optional. |
 
 [0]: #aws
 [1]: #gcp

pkg/cloudprovider/gcp/volume_snapshotter.go

@@ -38,8 +38,8 @@ import (
 )
 
 const (
-	projectKey          = "project"
 	zoneSeparator       = "__"
+	projectKey          = "project"
 	snapshotLocationKey = "snapshotLocation"
 )
 
@@ -55,15 +55,22 @@ func NewVolumeSnapshotter(logger logrus.FieldLogger) *VolumeSnapshotter {
 }
 
 func (b *VolumeSnapshotter) Init(config map[string]string) error {
-	if err := cloudprovider.ValidateVolumeSnapshotterConfigKeys(config, snapshotLocationKey); err != nil {
+	if err := cloudprovider.ValidateVolumeSnapshotterConfigKeys(config, snapshotLocationKey, projectKey); err != nil {
 		return err
 	}
 
 	b.snapshotLocation = config[snapshotLocationKey]
 
-	project, err := extractProjectFromCreds()
-	if err != nil {
-		return err
+	// take 'project' from config if specified, otherwise get it
+	// from the credentials file
+	if val := config[projectKey]; val != "" {
+		b.project = val
+	} else {
+		project, err := extractProjectFromCreds()
+		if err != nil {
+			return err
+		}
+		b.project = project
 	}
 
 	client, err := google.DefaultClient(oauth2.NoContext, compute.ComputeScope)
@@ -77,7 +84,6 @@ func (b *VolumeSnapshotter) Init(config map[string]string) error {
 	}
 
 	b.gce = gce
-	b.project = project
 
 	return nil
 }