src/cloud-prune: Minor fixes to handle edge cases

Removed gcp-project switch since we can access that from meta.json.
Handle AWS ami/snapshot pruning to take either of the resources
to be deleted than needing both of them. Also, exit gracefully when
we have no policy defined for the respective stream. Additionally,
added handling of some edge cases in handle_upload_builds_json

Author: gursewak1997

src/cmd-cloud-prune

@@ -60,7 +60,6 @@ def parse_args():
     parser.add_argument("--upload-builds-json", help="Push builds.json", action='store_true')
     parser.add_argument("--stream", type=str, help="CoreOS stream", required=True)
     parser.add_argument("--gcp-json-key", help="GCP Service Account JSON Auth", default=os.environ.get("GCP_JSON_AUTH"))
-    parser.add_argument("--gcp-project", help="GCP Project name", default=os.environ.get("GCP_PROJECT_NAME"))
     parser.add_argument("--acl", help="ACL for objects", action='store', default='private')
     parser.add_argument("--aws-config-file", default=os.environ.get("AWS_CONFIG_FILE"), help="Path to AWS config file")
     return parser.parse_args()
@@ -98,7 +97,11 @@ def main():
 
     with open(args.policy, "r") as f:
         policy = yaml.safe_load(f)
-    validate_policy(stream, policy)
+    if stream in policy:
+        validate_policy(stream, policy)
+    else:
+        print(f"There is no policy defined in gc-policy.yaml for {stream}")
+        return
 
     with open(BUILDFILES['list'], "r") as f:
         builds_json_data = json.load(f)
@@ -159,7 +162,6 @@ def get_cloud_config(args):
     return {
         "gcp": {
             "json-key": args.gcp_json_key,
-            "project": args.gcp_project
         },
         "aws": {
             "credentials": args.aws_config_file
@@ -207,15 +209,24 @@ def save_builds_json(builds_json_data):
 
 def handle_upload_builds_json(s3_client, bucket, prefix, dry_run, acl):
     remote_builds_json = get_json_from_s3(s3_client, bucket, os.path.join(prefix, "builds.json"))
+    # This is the copy of builds.json from what we last downloaded from the source
     with open(BUILDFILES['sourcedata'], "r") as f:
         builds_json_source_data = json.load(f)
+    # This is the current list of builds at builds/builds.json
+    with open(BUILDFILES['list'], "r") as f:
+        current_builds_json = json.load(f)
+
+    # If there are no changes to the local builds/builds.json we won't need to upload
+    # anything to the s3 bucket. Will return in this scenario.
+    if builds_json_source_data == current_builds_json:
+        print("There are no changes to the local builds/builds.json. No upload needed")
+        return
+
     # Check if there are any changes that were made to remote(s3 version) builds.json
     # while the pruning was in progress
     if remote_builds_json != builds_json_source_data:
         print("Detected remote updates to builds.json. Merging it to the local builds.json file")
-        with open(BUILDFILES['list'], "r") as f:
-            current_builds_json = json.load(f)
-            update_policy_cleanup(current_builds_json, remote_builds_json)
+        remote_builds_json = update_policy_cleanup(current_builds_json, remote_builds_json)
         if not dry_run:
             # Make sure we have the merged json as local builds/builds.json
             save_builds_json(remote_builds_json)
@@ -232,6 +243,7 @@ def update_policy_cleanup(current_builds, remote_builds):
             current_build = current_builds_dict[build_id]
             if 'policy-cleanup' in current_build:
                 remote_build['policy-cleanup'] = current_build['policy-cleanup']
+    return remote_builds
 
 
 def prune_cloud_uploads(build, cloud_config, dry_run):
@@ -257,7 +269,7 @@ def deregister_aws_amis(build, cloud_config, dry_run):
         if dry_run:
             print(f"Would delete {ami_id} and {snapshot_id} for {build.id}")
             continue
-        if ami_id and snapshot_id and region_name:
+        if (ami_id or snapshot_id) and region_name:
             try:
                 deregister_aws_resource(ami_id, snapshot_id, region=region_name, credentials_file=aws_credentials)
             except Exception as e:
@@ -274,8 +286,8 @@ def delete_gcp_image(build, cloud_config, dry_run):
         print(f"No GCP image for {build.id} for {build.arch}")
         return errors
     gcp_image = gcp.get("image")
+    project = gcp.get("project")
     json_key = cloud_config.get("gcp", {}).get("json-key")
-    project = cloud_config.get("gcp", {}).get("project")
     if dry_run:
         print(f"Would delete {gcp_image} GCP image for {build.id}")
     elif gcp_image and json_key and project: