89f5be005d
SeaweedFS Rust workers
weed/pb/plugin.proto is a language-agnostic contract: a maintenance worker
connects out to admin, announces the job types it can detect and execute, and
answers requests on that one stream. weed worker -admin=host:23646 is the Go
implementation of it from outside the admin process. This workspace is the Rust
one.
crates/core the contract: stream, handshake, heartbeat, registry, config forms
crates/lance maintenance jobs for Lance tables, and a binary
core knows nothing about any job. A second worker is a new crate beside
lance that depends on it, not a fork of the protocol.
Building
Requires Rust 1.94.1+ (2024 edition), matching rust-version in Cargo.toml.
The patch release matters: 1.94.0 does not build. The edition itself only needs
1.85; the higher floor comes from the dependency tree — lance's aws feature
pulls in the AWS SDK — so it moves with those crates. CI builds on the latest
stable.
core compiles plugin.proto with the protoc that protoc-bin-vendored ships,
the way seaweed-volume does, so it needs no system install.
The lance crates compile protos of their own, in their own build-script
processes, which nothing our build script sets can reach. They need a protoc of
their own: either one on PATH — brew install protobuf, apt install protobuf-compiler — or PROTOC naming one. CI points it at the vendored
binary for the runner's platform, resolved from the version in Cargo.lock.
Running
cargo run -p weed-lance-worker -- --admin 127.0.0.1:23646
The admin's HTTP address is what an operator has; the gRPC port is derived from it the way the Go side does. Dialling the HTTP port fails as "frame with invalid size", which reads like a protocol bug rather than a wrong port.
The binary is weed-worker, not weed-lance-worker: it is the Rust side of
weed worker, and lance is the first family of jobs it carries rather than the
only one it ever will.
Released builds do not need a toolchain. The worker ships inside the SeaweedFS
image, beside the Rust volume server, under the verb that mirrors
volume-rust:
docker run chrislusf/seaweedfs worker-rust --admin admin:23646
and as weed-worker_linux_{amd64,arm64}.tar.gz on each GitHub release. Both are
linux amd64/arm64 only — lance, arrow and datafusion make every extra target an
expensive build, and the worker runs beside the cluster it maintains. On an
architecture without a build the image carries an empty placeholder and the
entrypoint says so rather than failing as "not found".
Metrics
cargo run -p weed-lance-worker -- --admin 127.0.0.1:23646 --metrics-port 9328
Serves /health, /ready and /metrics on that port, the same three the Go
worker serves under weed worker -metricsPort, so one scrape config covers
workers in either language. Off by default, and bound to loopback unless
--metrics-ip says otherwise, because the endpoint is unauthenticated. 9328
continues the series the other components use (master 9324, volume 9325, filer
9326, s3 9327); an IPv6 address works with or without brackets.
Grafana: the "Plugin Workers" row of other/metrics/grafana_seaweedfs.json
graphs these. Its panels filter on $cluster, which comes from the scrape job's
labels, so scrape the worker the way the rest of the cluster is scraped or the
row stays empty.
Names are SeaweedFS_worker_*, matching the Go side's convention. The pair
worth alerting on is objects_seen_total and objects_skipped_total: a sweep
that proposes nothing and a sweep that could read nothing look identical from
proposals_total alone.
SeaweedFS_worker_connected 1
SeaweedFS_worker_objects_seen_total{job_type="lance_compact"} 7
SeaweedFS_worker_proposals_total{job_type="lance_compact"} 2
SeaweedFS_worker_jobs_total{job_type="lance_compact",result="ok"} 2
SeaweedFS_worker_lance_fragments_removed_total 25
/ready follows the control stream: a worker whose admin has gone away is
running but is not going to do anything.
Credentials
The worker holds none. It asks the namespace to describe a table with
vend_credentials and hands the storage_options that come back to lance. A
gateway without STS configured vends no credentials at all, so --access-key
and --secret-key supply a fallback; anything the namespace does vend wins over
them.
State
All three jobs are implemented and tested end to end against a live gateway:
compaction result: 12 fragments became 1
reindex result: 512 uncovered rows became 0
cleanup result: removed 14 versions and 24272 bytes
cargo test -p weed-lance-worker runs them when WEED_LANCE_NAMESPACE names a
live namespace and skips otherwise, the way the Go integration tests skip
without Docker. Each test seeds the table it needs, including building a vector
index and then appending rows outside it, so a run does not depend on what the
previous one left behind — the first version of these did, and quietly stopped
testing anything once it had done its job.
The handshake, descriptor exchange and heartbeat work against a live admin, which logs the worker connecting and prefetches all three descriptors.