Development setup

rcfg-sim is open source (MIT) and contributions are welcome. This page covers the local workflow; read Scope & versioning before proposing changes that touch user-facing surfaces.

Prerequisites

• Go 1.24+ (CI tests 1.24 and 1.25)
• make, git

git clone https://github.com/rconfig/rconfig-sim.git
cd rconfig-sim
make build

The pre-merge gate

Every PR must pass the same gate CI runs. Run it locally before pushing:

make fmt     # gofmt -s, no diff after running
make vet     # go vet, with and without the integration tag
make test    # unit tests, incl. determinism and metrics cardinality
make build   # both binaries compile

And for changes that touch the SSH path, the integration suite:

make integration   # real SSH listeners on loopback (build tag: integration)

Tests you should know about

• Determinism tests (TestRunDeterministic, TestCienaDeterministic) hash the generated output across two same-seed runs. Any change to template output for a given seed fails them by design; update the fixture only when the diff is intentional. See Determinism.
• Cardinality test asserts the Prometheus label sets stay bounded. Adding a label or value without updating it will fail. See Metrics overview.
• Characterization tests pin Cisco output (greeting, enable-mode flow, session close) so refactors stay byte-identical. Run make integration before and after a refactor.

Benchmarks

make bench

The hot path (command dispatch) benchmarks around 640 ns/op. Preserve the zero-copy path — no per-command allocations on show running-config. See Architecture.

Dependencies

The project intentionally depends on only three external libraries (golang.org/x/crypto, golang.org/x/sys, prometheus/client_golang). New dependencies need discussion first — see Scope.