WIP Introduce xcp-metrics-plugin-squeezed plugin for xcp-rrdd

xcp-metrics-plugin-squeezed is meant as a drop-in replacement for
rrdp-squeezed, as a first Rust-written brick for XAPI.

Metrics are read in Xenstore using the xenstore-rs bindings of
libxenstore, structured in a suitable way for upcoming OpenMetrics
support, and communicated to xcp-rrdd using its v2 protocol.

NOTE: while the full xcp-metrics work currently references external
git repository for xenstore-rs and xenctrl-rs as we had to add some
features there and the PRs are still pending, this initial work
explicitly does ot require any of those, and we went into some
gymnastics to support this, which reflects in the scripts extracting
this PR source code, as well as in parts of the code itself.

Signed-off-by: Teddy Astie <[email protected]>
Reviewed-by: Yann Dirson <[email protected]>

.github/workflows/rust.yml

@@ -0,0 +1,79 @@
+name: Rust
+
+on:
+  push:
+  pull_request:
+
+env:
+  CARGO_TERM_COLOR: always
+
+jobs:
+  build:
+    runs-on: ubuntu-latest
+    #container:
+    #  image: centos8 
+
+    steps:
+    - uses: actions/checkout@v3
+    - uses: actions-rs/toolchain@v1
+      with:
+        toolchain: 1.70.0
+        override: true
+    - name: Installing dependency packages
+      run: sudo apt update && sudo apt install -y libxen-dev protobuf-compiler
+
+    - name: Build
+      run: cargo build --verbose
+
+  doc:
+    runs-on: ubuntu-latest
+
+    steps:
+    - uses: actions/checkout@v3
+    - uses: actions-rs/toolchain@v1
+      with:
+        toolchain: 1.70.0
+        override: true
+    - name: Installing dependency packages
+      run: sudo apt update && sudo apt install -y libxen-dev protobuf-compiler
+
+    - name: Build docs
+      run: cargo doc --workspace --no-deps
+
+    - name: Upload docs
+      uses: actions/upload-artifact@v3
+      with:
+        name: rustdoc-html
+        path: ./target/doc
+
+  test:
+    runs-on: ubuntu-latest
+
+    steps:
+    - uses: actions/checkout@v3
+    - uses: actions-rs/toolchain@v1
+      with:
+        toolchain: nightly
+        override: true
+    - name: Installing dependency packages
+      run: sudo apt update && sudo apt install -y libxen-dev protobuf-compiler
+
+    - name: Run tests
+      run: |
+        cargo clean
+        cargo test --verbose
+      env:
+        CARGO_INCREMENTAL: '0'
+        RUSTFLAGS: '-Zprofile -Ccodegen-units=1 -Cinline-threshold=0 -Clink-dead-code -Coverflow-checks=off -Cpanic=abort -Zpanic_abort_tests'
+        RUSTDOCFLAGS: '-Zprofile -Ccodegen-units=1 -Cinline-threshold=0 -Clink-dead-code -Coverflow-checks=off -Cpanic=abort -Zpanic_abort_tests'
+
+    - name: Install grcov
+      run: cargo install grcov
+    - name: Test coverage report
+      run: grcov . -s . --binary-path ./target/debug/ -t html --branch --ignore-not-existing -o ./target/debug/coverage/
+
+    - name: Upload test coverage report
+      uses: actions/upload-artifact@v3
+      with:
+        name: coverage-html
+        path: ./target/debug/coverage/

.gitignore

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+/target
+/third-party/