Recording

Record a real service once, then test without it. A recording sends requests to the service, writes what it answered as mock files, and the server answers the same requests the same way from then on: in later test runs, in CI, and with no network.

HTTP

err := m.StartRecording(
	mockhttp.RecordDir("testdata/recorded"),
	mockhttp.RecordTarget("https://api.example.com"),
)
// ... requests to m reach the target, and are recorded ...
res, err := m.StopRecording(ctx) // writes the mock files, then serves them

gRPC

err := m.StartRecording(mockgrpc.RecordTarget("localhost:50051"), mockgrpc.RecordDir("testdata/grpc_recorded"))
// ... calls to m reach the target, and are recorded ...
res, err := m.StopRecording(ctx) // writes the mock files, then serves them

CLI

vlatte --record --record-target=https://api.example.com
# Ctrl-C writes the recordings; the next run serves them
vlatte

How it works

1. Take. With a target, the requests the recording takes go to the target before any mock. Without one, it takes what the server proxies already. Filters choose which requests it takes.
2. Write. Each answer becomes a mock file that matches its request, and no other, in testdata/vlatte/_mocks_recorded by default for HTTP, and _mocks_recorded under the gRPC root directory for gRPC.
3. Play back. Stopping the recording serves its files, and a server started later serves them too: they are mock files like any other, which you review and commit.

Page	What it covers
HTTP	What is recorded, filters, playback, what a recording matches and answers.
gRPC	How gRPC calls, streams included, are recorded and played back.
CLI, settings and admin API	Recording from the command line, from settings, and while a server runs.
Files and secrets	Where recordings go, and keeping secrets out of them.

The Record and replay guide builds a test helper that records on demand and replays otherwise.