GEN-55: Move sim-engine from hashintel/hash repo into /labs (#29)

* Add `engine`

* First attempt to run CI

* Attempt to fix CI

* `cargo fmt`

* Move to `sim-engine`

* Update apps/sim-engine/README.md

Co-authored-by: David @ HASH <[email protected]>

---------

Co-authored-by: David @ HASH <[email protected]>

.github/actions/install-rust-toolchain/action.yml

@@ -0,0 +1,42 @@
+name: Install Rust toolchain
+description: "Install Rust toolchain"
+
+inputs:
+  toolchain:
+    required: true
+    description: "Rust toolchain, e.g. 'stable' or 'nightly'"
+  working-directory:
+    description: "Working directory to run the action in"
+    required: false
+    default: "."
+
+runs:
+  using: "composite"
+  steps:
+    - name: "Install Rust"
+      working-directory: ${{ inputs.working-directory }}
+      shell: bash
+      run: |
+        # regex for components that are only available on nightly and should not be installed on stable
+        # these are in variables due to: https://stackoverflow.com/a/56449915/9077988
+        NIGHTLY_ONLY="miri|llvm-tools|llvm-tools-preview"
+        NIGHTLY_TOOLCHAIN="nightly-.*"
+
+        # extract components from the rust-toolchain.toml 
+        COMPONENTS=$(cat rust-toolchain.toml | yq -p toml '.toolchain.components[]')
+
+        rustup toolchain install "${{ inputs.toolchain }}"
+
+        for component in $COMPONENTS; do
+          # depending on the toolchain we need to conditionally skip specific components
+          if [[ ! "${{ inputs.toolchain }}" =~ $NIGHTLY_TOOLCHAIN ]]; then
+            # ensure that we only install components that are meant for stable
+            if [[ ! $component =~ $NIGHTLY_ONLY ]]; then
+              rustup component add --toolchain "${{ inputs.toolchain }}" "$component"
+            fi
+          else
+            rustup component add --toolchain "${{ inputs.toolchain }}" "$component"  
+          fi
+        done
+
+        echo "RUSTUP_TOOLCHAIN=${{ inputs.toolchain }}" >> $GITHUB_ENV

.github/actions/setup-rust-ci/action.yml

@@ -0,0 +1,16 @@
+name: Setup Rust CI
+description: Prepares Rust CI and installs Python to run scripts
+
+runs:
+  using: composite
+  steps:
+    - name: Set up Python
+      uses: actions/setup-python@61a6322f88396a6271a6ee3565807d608ecaddd1 # v4.7.0
+      with:
+        python-version: "3.10"
+    - name: Upgrade pip
+      shell: bash
+      run: python -m pip install --upgrade pip
+    - name: Install dependencies
+      shell: bash
+      run: pip install -r .github/scripts/rust/requirements.txt

.github/scripts/rust/requirements.txt

@@ -0,0 +1,2 @@
+pygit2 == 1.9.2
+toml == 0.10.2

.github/scripts/rust/setup.py

@@ -0,0 +1,182 @@
+"""
+Setup script for the Rust GitHub Actions.
+
+The output of this will be used as arguments for the GitHub Actions matrix.
+
+see: https://docs.github.com/en/actions/using-jobs/using-a-matrix-for-your-jobs
+"""
+
+import re
+import json
+import itertools
+import os
+import toml
+
+from fnmatch import fnmatch
+from pathlib import Path
+from pygit2 import Repository, Commit
+
+CWD = Path.cwd()
+
+# All jobs for all crates will run if any of these paths change
+ALWAYS_RUN_PATTERNS = [".github/**", ".config/**", ".cargo/**"]
+
+# We only run a subset of configurations for PRs, the rest will only be tested prior merging
+IS_PULL_REQUEST_EVENT = "GITHUB_EVENT_NAME" in os.environ and os.environ["GITHUB_EVENT_NAME"] == "pull_request"
+
+
+def generate_diffs():
+    """
+    Generates a diff between `HEAD^` and `HEAD`
+    """
+
+    repository = Repository(CWD)
+    head = repository.head.peel(Commit)
+    return repository.diff(head.parents[0], head, context_lines=0)
+
+
+def find_local_crates():
+    """
+    Returns all available crates in the workspace.
+
+    If a crate is in a sub-crate of another crate, only the super-crate will be returned because
+    the sub-crates will be picked up by `cargo` automatically.
+    :return: a list of crate paths
+    """
+    return [path.relative_to(CWD).parent for path in CWD.rglob("Cargo.toml") if find_toolchain(path.parent)]
+
+
+def find_toolchain(crate):
+    """
+    Returns the toolchain for the specified crate.
+
+    The toolchain is determined by the `rust-toolchain.toml` file in the crate's directory or any parent directory
+    :param crate: the path to the crate
+    :return: the toolchain for the crate
+    """
+    directory = crate
+    root = Path(directory.root)
+
+    while directory != root:
+        toolchain_file = directory / "rust-toolchain.toml"
+        if toolchain_file.exists():
+            toolchain = toml.load(toolchain_file).get("toolchain", {}).get("channel")
+            if toolchain:
+                return toolchain
+        directory = directory.parent
+
+    return None
+
+
+
+def filter_parent_crates(crates):
+    checked_crates = []
+    for crate in crates:
+        if not any(path in crate.parents for path in crates):
+            checked_crates.append(crate)
+    return checked_crates
+
+
+def filter_for_changed_crates(diffs, crates):
+    """
+    Returns a list of paths to crates which have changed files
+
+    If a file was changed, which matches `ALWAYS_RUN_PATTERNS`, all crates will be returned
+    :param diffs: a list `Diff`s returned from git
+    :param crates: a list of paths to crates
+    :return: a list of crate paths
+    """
+    # Check if any changed file matches `ALWAYS_RUN_PATTERNS`
+    if any(
+        fnmatch(diff.delta.new_file.path, pattern)
+        for diff in diffs
+        for pattern in ALWAYS_RUN_PATTERNS
+    ):
+        return crates
+
+    # Get the unique crate paths which have changed files
+    return list(
+        {
+            crate
+            for crate in crates
+            for diff in diffs
+            if fnmatch(diff.delta.new_file.path, f"{crate}/**")
+        }
+    )
+
+
+def output_matrix(name, github_output_file, crates, **kwargs):
+    """
+    Outputs the job matrix for the given crates
+    :param name: The name where the list of crates will be stored to be read by GitHub Actions
+    :param crates: a list of paths to crates
+    """
+
+    crate_names = {}
+    for crate in crates:
+        with open(
+                crate / "Cargo.toml", "r", encoding="UTF-8"
+        ) as cargo_toml:
+            cargo_toml_obj = toml.loads(cargo_toml.read())
+            if "package" in cargo_toml_obj and "name" in cargo_toml_obj["package"]:
+                crate_names[crate] = cargo_toml_obj["package"]["name"]
+            else:
+                crate_names[crate] = str(crate.name.replace("_", "-"))
+
+    available_toolchains = set()
+    used_toolchain_combinations = []
+
+    for crate in crates:
+        toolchain = find_toolchain(crate)
+        available_toolchains.add(toolchain)
+        toolchains = [toolchain]
+
+        used_toolchain_combinations.append(
+            itertools.product([crate_names[crate]], toolchains, repeat=1)
+        )
+
+    available_toolchain_combinations = itertools.product(crate_names.values(), available_toolchains)
+    excluded_toolchain_combinations = set(available_toolchain_combinations).difference(
+        *used_toolchain_combinations
+    )
+
+    matrix = dict(
+        name=[crate_names[crate] for crate in crates],
+        toolchain=list(available_toolchains),
+        **kwargs,
+        exclude=[
+            dict(name=elem[0], toolchain=elem[1])
+            for elem in excluded_toolchain_combinations
+        ],
+        include=[
+            dict(name=crate_names[crate], directory=str(crate))
+            for crate in crates
+        ],
+    )
+
+    if len(matrix["name"]) == 0:
+        matrix = {}
+
+    github_output_file.write(f"{name}={json.dumps(matrix)}\n")
+    print(f"Job matrix for {name}: {json.dumps(matrix, indent=4)}")
+
+
+def main():
+    diffs = generate_diffs()
+    available_crates = find_local_crates()
+    changed_crates = filter_for_changed_crates(diffs, available_crates)
+    changed_parent_crates = filter_parent_crates(changed_crates)
+
+    github_output_file = open(os.environ["GITHUB_OUTPUT_FILE_PATH"], "w")
+
+    output_matrix("lint", github_output_file, changed_parent_crates)
+    if IS_PULL_REQUEST_EVENT:
+        output_matrix("test", github_output_file, changed_parent_crates, profile=["dev"])
+    else:
+        output_matrix("test", github_output_file, changed_parent_crates, profile=["dev", "release"])
+
+    github_output_file.close()
+
+
+if __name__ == "__main__":
+    main()