seaweedfs/seaweed-worker/README.md

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:12535 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

It also depends on ../seaweed-common, a small crate outside this workspace holding the few helpers the Rust volume server needs identically — the HTTP<->gRPC address rule and the rustls provider choice.

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 127.0.0.1:12535

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:12535

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 127.0.0.1:12535 --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.

In a vector bucket's vector namespace the gateway vends write credentials only to a caller that proves it holds jwt.filer_signing.key. Pass that key with --filer-signing-key so compaction, cleanup and index builds can rewrite vector indexes.

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.