feat(inter-op): make Dockerfile generic over test binary (#3382)

We make the binary that should be copied into the container configurable via a build time `ARG`. This will allow us to reuse the same `Dockerfile` once we write more tests.
Additionally, this allows us to remove some of the directory switching and creation code. In order to not send the entire repository over to the docker daemon as a build context, we introduce a `.dockerignore` file that only allows select binary to be sent over.

The downside of this is that we need to extend this ignore file every time we add a new test. This shouldn't happen very often though and is easily discovered because the building of the docker container will fail.

.dockerignore

@@ -0,0 +1,10 @@
+# This Docker ignore file aims to optimise the build process of the interop tests.
+# The Dockerfile in ./interop-tests/Dockerfile copies a locally built binary into the container and
+# thus does not need anything else to be present in the working directory.
+*
+
+# CI will build and copy over the release binary.
+!target/release/ping
+
+# Locally, we might want to build it as `debug` binary to accelerate the build process.
+!target/debug/ping

.github/workflows/interop-test.yml

@@ -24,13 +24,10 @@ jobs:
       - name: Install Protoc
         run: sudo apt-get install protobuf-compiler
       - name: Build image
-        working-directory: ./interop-tests
         run: |
           cargo build --release -p interop-tests
-          mkdir -p target/release/
-          cp ../target/release/ping target/release
-          docker build -t rust-libp2p-head .
-          docker image save -o ping-image.tar rust-libp2p-head
+          docker build -t rust-libp2p-head --build-arg=TEST_BINARY=target/release/ping . -f ./interop-tests/Dockerfile
+          docker image save -o ./interop-tests/ping-image.tar rust-libp2p-head
       - name: Upload ping versions info
         uses: actions/upload-artifact@v3
         with:

interop-tests/Dockerfile

@@ -1,4 +1,5 @@
 FROM ubuntu:22.04
-COPY target/release/ping /usr/local/bin/testplan
+ARG TEST_BINARY
+COPY $TEST_BINARY /usr/local/bin/testplan
 ENV RUST_BACKTRACE=1
 ENTRYPOINT ["testplan"]