Consider Subsystem Logger with Protocol Request and Response Data about terraform-plugin-go

[bflad]

Quick msgpack notes:

b, _ := msgpack.Marshal(/* ... */)
fmt.Printf("Bytes: %v", b) // [142 161 98 207 0 0 0 0 0 0 0 5 161 100 ...

var ret interface{}
decoder := msgpack.NewDecoder(bytes.NewReader(b))
decoder.UseDecodeInterfaceLoose(true)
err := decoder.Decode(&ret)
fmt.Printf("Friendlier: %v", ret) // map[a:5 b:5 c:5 d:true e:foo f:[102 111 111] ...

[bflad]

Since the data is a little unwieldy, maybe this could dump files separately from the logging. e.g. {TIMESTAMP}_{RPC}_(request|response).msgpack then those could be inspected.

Some additional references for inspection tooling:

• https://github.com/tagomoris/msgpack-inspect
• https://pkg.go.dev/github.com/nokute78/msgpack-microscope
• https://pkg.go.dev/github.com/nokute78/msgpack-microscope/cmd/msgpack2json (and jq)
• wader/fq#25

[bflad]

To flush out the file-based proposal a little more:

Support a new environment variable, TF_LOG_SDK_PROTO_DATA_DIR, which sets a directory to save request and response DynamicValue data. When set and a RPC request or response with DynamicValue data crosses the server logic, open a file and save the raw data:

• If len(msgpack) > 0, {TIMESTAMP}_{RPC}_(Request|Response|{MESSAGE})_{FIELD}.msgpack
• If len(json) > 0, {TIMESTAMP}_{RPC}_(Request|Response|{MESSAGE})_{FIELD}.json

Enabling this also should automatically trace log the filenames as they are created.