Add --editable flag to complement.sh which uses an editable install of Synapse for faster turn-around times whilst developing iteratively. (#14548)

Co-authored-by: Mathieu Velten <mathieuv@matrix.org>

scripts-dev/complement.sh

@@ -53,6 +53,12 @@ Run the complement test suite on Synapse.
         Only build the Docker images. Don't actually run Complement.
         Conflicts with -f/--fast.
 
+  -e, --editable
+        Use an editable build of Synapse, rebuilding the image if necessary.
+        This is suitable for use in development where a fast turn-around time
+        is important.
+        Not suitable for use in CI in case the editable environment is impure.
+
 For help on arguments to 'go test', run 'go help testflag'.
 EOF
 }
@@ -73,6 +79,9 @@ while [ $# -ge 1 ]; do
         "--build-only")
             skip_complement_run=1
             ;;
+        "-e"|"--editable")
+            use_editable_synapse=1
+            ;;
         *)
             # unknown arg: presumably an argument to gotest. break the loop.
             break
@@ -96,25 +105,76 @@ if [[ -z "$COMPLEMENT_DIR" ]]; then
   echo "Checkout available at 'complement-${COMPLEMENT_REF}'"
 fi
 
+if [ -n "$use_editable_synapse" ]; then
+    if [[ -e synapse/synapse_rust.abi3.so ]]; then
+        # In an editable install, back up the host's compiled Rust module to prevent
+        # inconvenience; the container will overwrite the module with its own copy.
+        mv -n synapse/synapse_rust.abi3.so synapse/synapse_rust.abi3.so~host
+        # And restore it on exit:
+        synapse_pkg=`realpath synapse`
+        trap "mv -f '$synapse_pkg/synapse_rust.abi3.so~host' '$synapse_pkg/synapse_rust.abi3.so'" EXIT
+    fi
+
+    editable_mount="$(realpath .):/editable-src:z"
+    if docker inspect complement-synapse-editable &>/dev/null; then
+        # complement-synapse-editable already exists: see if we can still use it:
+        # - The Rust module must still be importable; it will fail to import if the Rust source has changed.
+        # - The Poetry lock file must be the same (otherwise we assume dependencies have changed)
+
+        # First set up the module in the right place for an editable installation.
+        docker run --rm -v $editable_mount --entrypoint 'cp' complement-synapse-editable -- /synapse_rust.abi3.so.bak /editable-src/synapse/synapse_rust.abi3.so
+
+        if (docker run --rm -v $editable_mount --entrypoint 'python' complement-synapse-editable -c 'import synapse.synapse_rust' \
+            && docker run --rm -v $editable_mount --entrypoint 'diff' complement-synapse-editable --brief /editable-src/poetry.lock /poetry.lock.bak); then
+            skip_docker_build=1
+        else
+            echo "Editable Synapse image is stale. Will rebuild."
+            unset skip_docker_build
+        fi
+    fi
+fi
+
 if [ -z "$skip_docker_build" ]; then
-    # Build the base Synapse image from the local checkout
-    echo_if_github "::group::Build Docker image: matrixdotorg/synapse"
-    docker build -t matrixdotorg/synapse \
-      --build-arg TEST_ONLY_SKIP_DEP_HASH_VERIFICATION \
-      --build-arg TEST_ONLY_IGNORE_POETRY_LOCKFILE \
-      -f "docker/Dockerfile" .
-    echo_if_github "::endgroup::"
+    if [ -n "$use_editable_synapse" ]; then
 
-    # Build the workers docker image (from the base Synapse image we just built).
-    echo_if_github "::group::Build Docker image: matrixdotorg/synapse-workers"
-    docker build -t matrixdotorg/synapse-workers -f "docker/Dockerfile-workers" .
-    echo_if_github "::endgroup::"
+        # Build a special image designed for use in development with editable
+        # installs.
+        docker build -t synapse-editable \
+            -f "docker/editable.Dockerfile" .
 
-    # Build the unified Complement image (from the worker Synapse image we just built).
-    echo_if_github "::group::Build Docker image: complement/Dockerfile"
-    docker build -t complement-synapse \
-           -f "docker/complement/Dockerfile" "docker/complement"
-    echo_if_github "::endgroup::"
+        docker build -t synapse-workers-editable \
+            --build-arg FROM=synapse-editable \
+            -f "docker/Dockerfile-workers" .
+
+        docker build -t complement-synapse-editable \
+            --build-arg FROM=synapse-workers-editable \
+            -f "docker/complement/Dockerfile" "docker/complement"
+
+        # Prepare the Rust module
+        docker run --rm -v $editable_mount --entrypoint 'cp' complement-synapse-editable -- /synapse_rust.abi3.so.bak /editable-src/synapse/synapse_rust.abi3.so
+
+    else
+
+        # Build the base Synapse image from the local checkout
+        echo_if_github "::group::Build Docker image: matrixdotorg/synapse"
+        docker build -t matrixdotorg/synapse \
+        --build-arg TEST_ONLY_SKIP_DEP_HASH_VERIFICATION \
+        --build-arg TEST_ONLY_IGNORE_POETRY_LOCKFILE \
+        -f "docker/Dockerfile" .
+        echo_if_github "::endgroup::"
+
+        # Build the workers docker image (from the base Synapse image we just built).
+        echo_if_github "::group::Build Docker image: matrixdotorg/synapse-workers"
+        docker build -t matrixdotorg/synapse-workers -f "docker/Dockerfile-workers" .
+        echo_if_github "::endgroup::"
+
+        # Build the unified Complement image (from the worker Synapse image we just built).
+        echo_if_github "::group::Build Docker image: complement/Dockerfile"
+        docker build -t complement-synapse \
+            -f "docker/complement/Dockerfile" "docker/complement"
+        echo_if_github "::endgroup::"
+
+    fi
 fi
 
 if [ -n "$skip_complement_run" ]; then
@@ -123,6 +183,10 @@ if [ -n "$skip_complement_run" ]; then
 fi
 
 export COMPLEMENT_BASE_IMAGE=complement-synapse
+if [ -n "$use_editable_synapse" ]; then
+    export COMPLEMENT_BASE_IMAGE=complement-synapse-editable
+    export COMPLEMENT_HOST_MOUNTS="$editable_mount"
+fi
 
 extra_test_args=()