Upstream Modes v3.9.0

Upstream modes define how GripMock handles requests when reflection sources are used.

⚠️ EXPERIMENTAL FEATURE: Upstream modes (proxy, replay, capture) are experimental and may change without notice.

Modes at a glance

• proxy: pure reverse proxy through GripMock.
• replay: local stubs first, upstream fallback on real matcher miss.
• capture: replay behavior plus automatic recording of upstream misses.

Why this matters

For a typical Order Service rollout, modes let you move in predictable stages:

1. Start with proxy to route all traffic through GripMock and inspect real calls.
2. Move to replay when you have initial stubs and still need upstream fallback.
3. Use capture to accelerate coverage and transition away from live dependency.

Reflection vs mode

• Reflection source (grpc://, grpcs://) => how descriptors are loaded.
• Upstream mode (+proxy, +replay, +capture) => how runtime requests are resolved.

URL schemes

• grpc+proxy://host:port
• grpc+replay://host:port
• grpc+capture://host:port
• grpcs+proxy://host:port
• grpcs+replay://host:port
• grpcs+capture://host:port

Multi-source mode binding

When multiple sources are provided:

• the mode applies only to services registered from that source;
• if a service exists in multiple sources, first source wins for that service;
• later sources do not override already-bound services.

Example:

gripmock \
  grpc+proxy://proxy:123 \
  grpc+replay://proxy1:321 \
  grpc+capture://proxy2:444

If services overlap like (greeter greeter1) (greeter1 greeter2) (greeter2 greeter3), final binding is:

• greeter, greeter1 -> proxy
• greeter2 -> replay
• greeter3 -> capture

Detailed pages

• Proxy mode
• Replay mode
• Capture mode