cloud-cleaner: clean up image and vm after GCP integration test

Extend internal GCP library to allow deleting Compute Node image and
instance. In addition provide function to load service account
credentials file content from the environment.

Change names used for GCP image and instance in `api.sh` integration
test to make them predictable. This is important, so that cloud-cleaner
can identify potentially left over resources and clean them up. Use the
same approach for generating predictable, but run-specific, test ID as
in GenerateCIArtifactName() from internal/test/helpers.go. Use SHA224
to generate a hash from the string, because it can contain characters
not allowed by GCP for resource name (specifically "_" e.g. in "x86_64").
SHA-224 was picked because it generates short enough output and it is
future proof for use in RHEL (unlike MD5 or SHA-1).

Refactor cloud-cleaner to clean up GCP resources and also to run cleanup
for each cloud in a separate goroutine.

Modify run_cloud_cleaner.sh to be able to run in environment in which
AZURE_CREDS is not defined.

Always run cloud-cleaner after integration tests for rhel8, rhel84 and
cs8, which test GCP.

Define DISTRO_CODE for each integration testing stage in Jenkinsfile.

Signed-off-by: Tomas Hozza <thozza@redhat.com>

internal/cloud/gcp/compute.go

@@ -204,3 +204,40 @@ func (g *GCP) ComputeImageShare(imageName string, shareWith []string) error {
 
 	return nil
 }
+
+// ComputeImageDelete deletes a Compute Node image with the given name. If the
+// image existed and was successfully deleted, no error is returned.
+//
+// Uses:
+//	- Compute Engine API
+func (g *GCP) ComputeImageDelete(image string) error {
+	ctx := context.Background()
+
+	computeService, err := compute.NewService(ctx, option.WithCredentials(g.creds))
+	if err != nil {
+		return fmt.Errorf("failed to get Compute Engine client: %v", err)
+	}
+
+	_, err = computeService.Images.Delete(g.creds.ProjectID, image).Context(ctx).Do()
+
+	return err
+}
+
+// ComputeInstanceDelete deletes a Compute Node instance with the given name and
+// running in the given zone. If the instance existed and was successfully deleted,
+// no error is returned.
+//
+// Uses:
+//	- Compute Engine API
+func (g *GCP) ComputeInstanceDelete(zone, instance string) error {
+	ctx := context.Background()
+
+	computeService, err := compute.NewService(ctx, option.WithCredentials(g.creds))
+	if err != nil {
+		return fmt.Errorf("failed to get Compute Engine client: %v", err)
+	}
+
+	_, err = computeService.Instances.Delete(g.creds.ProjectID, zone, instance).Context(ctx).Do()
+
+	return err
+}

internal/cloud/gcp/gcp.go

@@ -3,6 +3,8 @@ package gcp
 import (
 	"context"
 	"fmt"
+	"io/ioutil"
+	"os"
 
 	cloudbuild "cloud.google.com/go/cloudbuild/apiv1"
 	"cloud.google.com/go/storage"
@@ -10,6 +12,12 @@ import (
 	"google.golang.org/api/compute/v1"
 )
 
+// GCPCredentialsEnvName contains name of the environment variable used
+// to specify the path to file with CGP service account credentials
+const (
+	GCPCredentialsEnvName string = "GOOGLE_APPLICATION_CREDENTIALS"
+)
+
 // GCP structure holds necessary information to authenticate and interact with GCP.
 type GCP struct {
 	creds *google.Credentials
@@ -49,6 +57,29 @@ func New(credentials []byte) (*GCP, error) {
 	return &GCP{creds}, nil
 }
 
+// GetCredentialsFromEnv reads the service account credentials JSON file from
+// the path pointed to by the environment variable name stored in
+// 'GCPCredentialsEnvName'. If the content of the JSON file was read successfully,
+// its content is returned as []byte, otherwise nil is returned with proper error.
+func GetCredentialsFromEnv() ([]byte, error) {
+	credsPath, exists := os.LookupEnv(GCPCredentialsEnvName)
+
+	if !exists {
+		return nil, fmt.Errorf("'%s' env variable is not set", GCPCredentialsEnvName)
+	}
+	if credsPath == "" {
+		return nil, fmt.Errorf("'%s' env variable is empty", GCPCredentialsEnvName)
+	}
+
+	var err error
+	credentials, err := ioutil.ReadFile(credsPath)
+	if err != nil {
+		return nil, fmt.Errorf("Error while reading credentials file: %s", err)
+	}
+
+	return credentials, nil
+}
+
 // GetProjectID returns a string with the Project ID of the project, used for
 // all GCP operations.
 func (g *GCP) GetProjectID() string {