Services Overview

floci-gcp emulates GCP services on a single port (4588). All services use real GCP wire protocols — your existing GCP SDK calls and gcloud CLI commands work without modification.

Service Matrix

Service	Protocol	Endpoint
Cloud Storage (GCS)	REST XML (objects) + REST JSON (management)	/{bucket}/{object}, /storage/v1/b/{bucket}
Pub/Sub	gRPC	google.pubsub.v1.Publisher, google.pubsub.v1.Subscriber
Firestore	gRPC	google.firestore.v1.Firestore
Datastore	HTTP/protobuf	/v1/projects/{project}:{method}
Secret Manager	gRPC	google.cloud.secretmanager.v1.SecretManagerService
IAM	REST JSON	/v1/projects/{project}/serviceAccounts
Managed Kafka	REST JSON	/v1/projects/{project}/locations/{location}/clusters

Single-Port Design

All services — gRPC and REST — are available on port 4588 via ALPN negotiation:

• http2=true — enables HTTP/2 support
• grpc.server.use-separate-server=false — gRPC and REST share the same port

Clients using plain HTTP/1.1 are served REST endpoints. Clients using HTTP/2 (gRPC) are served gRPC endpoints. No separate ports or proxy configuration is required.

Common Setup

Before calling any service, set the appropriate emulator environment variable:

export PUBSUB_EMULATOR_HOST=localhost:4588
export FIRESTORE_EMULATOR_HOST=localhost:4588
export DATASTORE_EMULATOR_HOST=localhost:4588
export STORAGE_EMULATOR_HOST=http://localhost:4588
export SECRET_MANAGER_EMULATOR_HOST=localhost:4588

GCP SDKs automatically bypass credential validation when these variables are set.

For gcloud CLI:

gcloud config set project floci-local

Auth Bypass

floci-gcp does not validate credentials. All requests are accepted unconditionally. This matches the behavior of GCP official emulators when *_EMULATOR_HOST is set.

Multi-Project Isolation

All resources are namespaced by GCP project ID. Resources in project-a are invisible to project-b. See Multi-Project Isolation.