workspace: split into prometheus-expfmt, prometheus-relabel, and prometheus-scrape-manager

.github/workflows/ci.yml

@@ -29,13 +29,13 @@ jobs:
       - name: Check formatting (OTAP compatibility suite)
         run: cargo fmt --manifest-path tests/otap-compat/Cargo.toml --all -- --check
       - name: Run clippy
-        run: cargo clippy --all-targets --all-features -- -D warnings
+        run: cargo clippy --workspace --all-targets --all-features -- -D warnings
       - name: Run clippy (no default features)
-        run: cargo clippy --all-targets --no-default-features -- -D warnings
+        run: cargo clippy --workspace --all-targets --no-default-features -- -D warnings
       - name: Run tests (all features)
-        run: cargo test --all-features
+        run: cargo test --workspace --all-features
       - name: Run tests (no default features)
-        run: cargo test --no-default-features
+        run: cargo test --workspace --no-default-features
       - name: Run clippy (OTAP compatibility suite)
         env:
           CARGO_TARGET_DIR: target
@@ -53,9 +53,9 @@ jobs:
       - uses: dtolnay/rust-toolchain@1.88
       - uses: Swatinem/rust-cache@v2
       - name: Check MSRV (all features)
-        run: cargo check --all-targets --all-features
+        run: cargo check --workspace --all-targets --all-features
       - name: Check MSRV (no default features)
-        run: cargo check --all-targets --no-default-features
+        run: cargo check --workspace --all-targets --no-default-features
 
   go-fixtures:
     name: Go testdata sync check

.github/workflows/release.yml

@@ -0,0 +1,77 @@
+name: Release
+
+on:
+  release:
+    types: [published]
+  workflow_dispatch:
+    inputs:
+      dry_run:
+        description: "Run cargo publish --dry-run without uploading to crates.io"
+        required: true
+        type: boolean
+        default: true
+
+permissions:
+  contents: read
+  id-token: write
+
+concurrency:
+  group: release-${{ github.ref }}
+  cancel-in-progress: false
+
+jobs:
+  publish:
+    name: Publish to crates.io
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+        with:
+          persist-credentials: false
+
+      - uses: dtolnay/rust-toolchain@stable
+
+      - name: Verify release tag matches workspace crate versions
+        if: github.event_name == 'release'
+        env:
+          TAG_NAME: ${{ github.event.release.tag_name }}
+        run: |
+          expected="${TAG_NAME#v}"
+          if [ "$expected" = "$TAG_NAME" ]; then
+            echo "Release tag '${TAG_NAME}' must start with 'v' (for example, v0.1.0)"
+            exit 1
+          fi
+          actual=$(cargo metadata --no-deps --format-version 1 \
+            | jq -r '.packages[] | select(.publish == null or (.publish | length > 0)) | "\(.name)@\(.version)"')
+          echo "Publishable crates:"
+          echo "$actual"
+          mismatched=$(cargo metadata --no-deps --format-version 1 \
+            | jq -r --arg expected "$expected" \
+              '.packages[] | select(.publish == null or (.publish | length > 0)) | select(.version != $expected) | "\(.name)@\(.version)"')
+          if [ -n "$mismatched" ]; then
+            echo "Release tag ${TAG_NAME} (version ${expected}) does not match crate versions:"
+            echo "$mismatched"
+            exit 1
+          fi
+
+      - name: Run workspace tests and doc checks
+        env:
+          RUSTDOCFLAGS: "--deny warnings"
+        run: |
+          cargo test --workspace --locked --all-features
+          cargo test --workspace --locked --no-default-features
+          cargo doc --workspace --locked --no-deps --all-features
+
+      - name: Dry-run workspace publish
+        if: github.event_name == 'workflow_dispatch' && inputs.dry_run
+        run: cargo publish --workspace --locked --dry-run
+
+      - name: Authenticate with crates.io (OIDC Trusted Publishing)
+        if: github.event_name == 'release' || (github.event_name == 'workflow_dispatch' && !inputs.dry_run)
+        id: crates-io-auth
+        uses: rust-lang/crates-io-auth-action@3268eb413133e2960fa4ae0e963ca76380c54cd9 # v1.0.6
+
+      - name: Publish workspace crates to crates.io
+        if: github.event_name == 'release' || (github.event_name == 'workflow_dispatch' && !inputs.dry_run)
+        env:
+          CARGO_REGISTRY_TOKEN: ${{ steps.crates-io-auth.outputs.token }}
+        run: cargo publish --workspace --locked

AGENTS.md

@@ -8,13 +8,13 @@ Run these before you push. CI runs the same commands, see [.github/workflows/ci.
 
 ```sh
 cargo fmt --all -- --check
-cargo clippy --all-targets --all-features -- -D warnings
-cargo clippy --all-targets --no-default-features -- -D warnings
-cargo test --all-features
-cargo test --no-default-features
+cargo clippy --workspace --all-targets --all-features -- -D warnings
+cargo clippy --workspace --all-targets --no-default-features -- -D warnings
+cargo test --workspace --all-features
+cargo test --workspace --no-default-features
 ```
 
-If you touch `src/arrow`, also run the OTAP compatibility suite. It has its own manifest:
+If you touch `crates/expfmt/src/arrow`, also run the OTAP compatibility suite. It has its own manifest:
 
 ```sh
 cargo test --manifest-path tests/otap-compat/Cargo.toml
@@ -24,7 +24,7 @@ Do not use Rust language or std features newer than `rust-version` in `Cargo.tom
 
 ## Spec
 
-[specs/SPEC.md](specs/SPEC.md) is the specification contract for `scrape.rs` (`expfmt`, `relabel`, and scrape pipeline integration). If you change behavior the spec describes, update the spec in the same PR.
+[specs/SPEC.md](specs/SPEC.md) is the specification contract for `scrape.rs` (`prometheus-expfmt`, `prometheus-relabel`, and `prometheus-scrape-manager`). If you change behavior the spec describes, update the spec in the same PR.
 
 ## Test data
 
@@ -46,7 +46,7 @@ If Rust must differ from Go on purpose, explain each difference in the PR body w
 
 - Write all benchmarks with [`benchfmt.rs`](https://github.com/bwplotka/benchfmt.rs) using `benchfmt::Suite` and `benchfmt::CountingAlloc` in `harness = false` `[[bench]]` targets so every benchmark emits Go [Benchmark Data Format](https://go.googlesource.com/proposal/+/master/design/14313-benchmark-format.md) lines with `ns/op`, `MB/s`, `B/op`, and `allocs/op` for [`benchstat`](https://pkg.go.dev/golang.org/x/perf/cmd/benchstat). Do not use Criterion or custom benchmark output formats.
 - Name benchmarks with `/key=value` sub-benchmark dimensions such as `Decode/case=alltypes.237mfs/mode=decode`, call `b.report_allocs()` and `while b.keep_running()`, and include a `Recommended CLI invocation:` doc comment at the top of each benchmark file.
-- Performance improvements and hot-path changes require running benchmarks before and after the change, for example `cargo bench --bench decode -- -bench '^BenchmarkDecode' -benchtime 1s -count 6 -cpu 2 -benchmem | tee ${bench}.txt`, and comparing with `benchstat before.txt after.txt`.
+- Performance improvements and hot-path changes require running benchmarks before and after the change, for example `cargo bench -p prometheus-expfmt --bench decode -- -bench '^BenchmarkDecode' -benchtime 1s -count 6 -cpu 2 -benchmem | tee ${bench}.txt`, and comparing with `benchstat before.txt after.txt`.
 - Always output benchmark results in raw `benchstat` format in the PR body and review comments, and always include links to the exact `before` and `after` commits that the benchmark refers to. Rerun benchmarks and update the commit links whenever addressing review comments that touch benchmarked code or benchmarks.
 - If a subset of benchmark results shows a regression, address it or explain in the PR body why that case is not important.
 - Reuse allocations in hot paths where possible, such as `Vec::clear`, scratch buffers, and interner arenas. When reusing buffers exposed through APIs or traits, document lifetime and copy requirements on the trait or type definition.

Cargo.toml

@@ -1,52 +1,39 @@
-[package]
-name = "expfmt"
+[workspace]
+resolver = "3"
+members = [
+    "crates/expfmt",
+    "crates/relabel",
+    "crates/scrape-manager",
+]
+exclude = ["tests/otap-compat"]
+
+[workspace.package]
 version = "0.1.0"
 edition = "2024"
 rust-version = "1.88"
-description = "Prometheus and OpenMetrics wire exposition format decoders"
 license = "Apache-2.0"
-repository = "https://github.com/prometheus/expfmt-rs"
-keywords = ["prometheus", "openmetrics", "metrics", "opentelemetry", "arrow"]
-categories = ["parser-implementations", "encoding"]
-
-[workspace]
-exclude = ["tests/otap-compat"]
+repository = "https://github.com/prometheus/scrape.rs"
 
-[features]
-default = ["arrow", "dto", "relabel"]
-arrow = ["dep:arrow-array", "dep:arrow-buffer", "dep:arrow-schema"]
-dto = ["dep:prost", "dep:prost-types"]
-relabel = ["dep:regex", "dep:serde"]
+[workspace.dependencies]
+prometheus-expfmt = { version = "0.1.0", path = "crates/expfmt", default-features = false }
+prometheus-relabel = { version = "0.1.0", path = "crates/relabel" }
 
-[dependencies]
-arrow-array = { version = "59", default-features = false, optional = true }
-arrow-buffer = { version = "59", default-features = false, optional = true }
-arrow-schema = { version = "59", default-features = false, optional = true }
-prost = { version = "0.14", optional = true }
-prost-types = { version = "0.14", optional = true }
-regex = { version = "1", optional = true }
-serde = { version = "1", features = ["derive"], optional = true }
-thiserror = "2"
-
-[dev-dependencies]
+arrow-array = { version = "59", default-features = false }
+arrow-buffer = { version = "59", default-features = false }
+arrow-schema = { version = "59", default-features = false }
 benchfmt = { git = "https://github.com/bwplotka/benchfmt.rs" }
+prost = { version = "0.14" }
 prost-build = "=0.14.4"
+prost-types = { version = "0.14" }
 protox = "0.10"
+regex = { version = "1" }
+serde = { version = "1", features = ["derive"] }
 serde_json = "1"
+thiserror = "2"
 
-[[bench]]
-name = "decode"
-harness = false
-required-features = ["arrow"]
-
-[[bench]]
-name = "relabel"
-harness = false
-required-features = ["relabel"]
-
-[lints.rust]
+[workspace.lints.rust]
 missing_docs = "warn"
 unsafe_code = "forbid"
 
-[lints.clippy]
+[workspace.lints.clippy]
 all = "warn"