internal/libhive: support simulator build configurations via --config

[danceratopz]

Adds --config to load client and simulator build configurations from a single YAML file. The file is a flat list in which each entry is either a client (client key) or a simulator (simulator key) with an optional Dockerfile extension and build arguments. Client entries use the existing --client-file format, so --client-file becomes an alias of --config: existing client files keep working unchanged and can gain simulator entries in place. This enables per-simulator configuration and selection of alternate Dockerfiles when available. The second commit replaces the initial --sim.file approach following review; --sim.file and --sim-file are removed.

- client: go-ethereum
  build_args:
    baseimage: docker.io/ethereum/client-go
    tag: latest
- simulator: ethereum/eels/consume-engine
  build_args:
    fixtures: stable@latest
    branch: ""
    disable_strict_exception_matching: nimbus-el

Run with ./hive --config devnet.yaml. Entries run in file order; --client filters the client entries when set explicitly, --sim filters the simulator entries using its existing regexp semantics, and --sim.buildarg overrides matching file arguments. A file without simulator entries matches --sim against the inventory as before, and a file without client entries uses the --client list, so client-only and simulator-only files are both valid. Unknown fields, entries with both or neither key, nametag on a simulator, unknown or duplicate simulators, missing alternate Dockerfiles, and empty files are rejected. Passing both --config and --client-file is an error. The file is optional. Without it, --client, --sim, --sim.buildarg and the default Dockerfile behave exactly as before, including hive_context.txt build contexts.

docs/commandline.md documents the file format and currently supported EELS examples. The documentation is intentionally minimal: no simulator ships an alternate Dockerfile yet, so the dockerfile field is described generically and the examples use only build arguments the current EELS simulators accept. The change adds configuration plumbing; simulator Dockerfiles and image publishing remain separate work.

Validation: gofmt, go test -race . ./internal/... ./hivesim/..., go vet . ./internal/... ./hivesim/..., go build, and git diff --check passed on the branch head. Regression tests cover parsing of client-only, simulator-only and mixed files, selection, argument precedence and isolation, and Docker build requests for default and alternate Dockerfiles with overridden contexts. CLI smoke checks verified both flag spellings, the alias conflict error, and error reporting for missing or invalid files. No live Docker simulation was run for this change.

Motivation

We'd like to start publishing images for EELS simulators and this mechanism is required to maintain support of building an arbitrary branch/ref from source (each eels Dockerfile would move to Dockerfile.git and be replaced with a minimal Dockerfile that pulls in a pre-built image).

[spencer-tb]

Thanks for adding this support! 2 potential paths before approving on my side :)

Let me know what you prefer, I'm happy with both!

1) Keep the current approach, and align the spelling.

Drop the --sim-file alias (hive.go:95) so --sim.file is the only form, and add --client.file:

./hive --sim.file simulators.yaml --client.file clients.yaml

2) Or switch to one file and one flag for both. Both parsers exist, so this is mostly wiring, i.e just use a single --configs flag:

# devnet8.yaml
clients:
  - client: go-ethereum
    build_args: { baseimage: docker.io/ethereum/client-go, tag: latest }
simulators:
  - simulator: ethereum/eels/consume-engine
    build_args: { tag: glamsterdam-devnet-8 }
  - simulator: ethereum/eels/consume-rlp
    dockerfile: git
    build_args: { branch: devnets/glamsterdam/8, fixtures: tests-glamsterdam-devnet@v8.1.4 }

./hive --config devnet8.yaml

--client and --sim stay as optional filters over the file, --client-file stays or is removed for --config.

[danceratopz]

Thanks for adding this support! 2 potential paths before approving on my side :)

Let me know what you prefer, I'm happy with both!

Thanks, good suggestions! I think it's cleaner to only require specifying a single file. --sim.file is gone!

2) Or switch to one file and one flag for both. Both parsers exist, so this is mostly wiring, i.e just use a single --configs flag:

# devnet8.yaml
clients:
  - client: go-ethereum
    build_args: { baseimage: docker.io/ethereum/client-go, tag: latest }
simulators:
  - simulator: ethereum/eels/consume-engine
    build_args: { tag: glamsterdam-devnet-8 }
  - simulator: ethereum/eels/consume-rlp
    dockerfile: git
    build_args: { branch: devnets/glamsterdam/8, fixtures: tests-glamsterdam-devnet@v8.1.4 }

./hive --config devnet8.yaml

--client and --sim stay as optional filters over the file, --client-file stays or is removed for --config.

There's a small tweak to the file format, so that we can alias --client-file to --config and keep it backwards compatible. Instead of top-level clients: and simulators: sections, the file stays a flat list and each entry is identified by its client or simulator key:

- client: go-ethereum
  build_args:
    baseimage: docker.io/ethereum/client-go
    tag: latest
- simulator: ethereum/eels/consume-engine
  build_args:
    fixtures: stable@latest
    branch: ""
- simulator: ethereum/eels/consume-rlp
  build_args:
    fixtures: stable@latest
    branch: ""

Then:

./hive --config devnet.yaml

Selection works as before: --client filters the client entries when set explicitly and --sim filters the simulator entries. A file without simulator entries falls back to matching --sim against the inventory, and a file without client entries falls back to the --client list, so a simulators-only file is valid too. E.g.,

./hive --config devnet.yaml --client go-ethereum --sim consume-engine

The only potential disadvantage is that we insist on a single file, so you can't mix and match client and simulator config files. But I don't think there's a real use case for mixing them, since our images are tied to mainnet or specific devnet configuration anyway.

I just pushed this change, but don't mind doing another round to get this right if need be!

[spencer-tb]

Awesome! I like that --client-file still works :)

Approved from my side! :)