libp2p-test-plans/multidim-interop/README.md

Interoperability test

This tests that different libp2p implementations can communicate with each other on each of their supported capabilities.

Each version of libp2p is defined in versions.ts. There the version defines its capabilities along with the id of its container image.

This repo and tests adhere to these constraints:

1. Be reproducible for a given commit.
2. Caching is an optimization. Things should be fine without it.
3. If we have a cache hit, be fast.

Test spec

The implementation is run in a container and is passed parameters via environment variables. The current parameters are:

Name	Description	Is Optional
transport	The transport to use	no
muxer	The muxer to use	no, except when transport is one of quic, quic-v1, webtransport
security	The security channel to use	no, except when transport is one of quic, quic-v1, webtransport
is_dialer	Should you dial or listen	no
ip	IP address to bind the listener to	yes, default to "0.0.0.0"
redis_addr	A different address to connect to redis (default redis:6379)	yes, default to the redis host on port 6379
test_timeout_seconds	Control the timeout of test.	yes, default to 180 seconds.

The test should do two different things depending on if it's the dialer or listener.

Running Locally

In some cases you may want to run locally when debugging, such as modifying internal dependencies.

1. To run the test locally, you'll also need to have docker installed in order to run the redis instance. Once docker is running, you can run the following command to start the redis instance:

docker run --rm -p 6379:6379 redis:7-alpine

This will start a redis instance on port 6379.

2. Next, you'll need to install the dependencies and build the implementation for the test. In this and the next step we are using a JS implementation as an example, so you would run the following command:

cd impl/js/v0.xx.xx/ && npm i && npm run build

3. Then you can run a dialer by running the following command, ensure that you pass the required environment variables, as well as any that may be of use for debugging:

DEBUG=*:yamux:trace transport=tcp muxer=yamux security=noise is_dialer=true   npm run test -- -t node

4. Finally you can run a listener by running the following command in this case where a running a rust listener:

 RUST_LOG=yamux=trace transport=tcp muxer=yamux security=noise is_dialer=false ip="0.0.0.0" redis_addr=localhost:6379  cargo run --package interop-tests

For more details on how to run a dialer vs a listener, see the sections below.

Dialer

The dialer should emit all diagnostic logs to stderr. Only the final JSON string result should be emitted to stdout.

1. Connect to the Redis instance.
2. Create a libp2p node as defined by the environment variables.
3. Get the listener's address via Redis' BLPOP using the listenerAddr key.
4. Record the current instant as handshakeStartInstant.
5. Connect to the listener.
6. Ping the listener, and record the round trip duration as pingRTT
7. Record the duration since handshakeStartInstant. This is handshakePlusOneRTT.
8. Print to stdout the JSON formatted string: {"handshakePlusOneRTTMillis": handshakePlusOneRTT, "pingRTTMilllis": pingRTT}. Durations should be printed in milliseconds as a float.
9. Exit with a code zero.

On error, the dialer should return a non-zero exit code.

Listener

The listener should emit all diagnostic logs to stderr.

1. Connect to the Redis instance.
2. Create a libp2p node as defined by the environment variables.
3. Publish the listener's address via Redis' RPUSH using the listenerAddr key.
4. Sleep for the duration of test_timeout_seconds. The test runner will kill this process when the dialer finishes.
5. If the timeout is hit, exit with a non-zero error code.

On error, the listener should return a non-zero exit code.

Caching

The caching strategy is opinionated in an attempt to make things simpler and faster. Here's how it works:

1. We cache the result of image.json in each implementation folder.
2. The cache key is derived from the hashes of the files in the implementation folder.
3. When loading from cache, if we have a cache hit, we load the image into docker and create the image.json file. We then call make -o image.json to allow the implementation to build any extra things from cache (e.g. JS-libp2p builds browser images from the same base as node). If we have a cache miss, we simply call make and build from scratch.
4. When we push the cache we use the cache-key along with the docker platform (arm64 vs x86_64).