Switch to roadrunner as the default runtime for docker images

[acelaya]

There have been lately a couple of reports of hard to fix low-level issues that can only be reproduced with openswoole.

Additionally, roadrunner is easier to install and manage in general, while the performance is basically the same, so it probably makes sense to do the transition and recommend using roadrunner.

The list of reasons includes, but it's not limited to:

• Memory leaks as requests increase.
  • Memory leak when running Openswoole Docker image #1740
• Random DB connection errors.
  • Randomly happening PDOException: SQLSTATE[HY000]: General error: 7 server closed the connection unexpectedly #1669
  • Intermittent operation: MySQL server has gone away, HTTP 500 and HTTP 502 errors with API calls #1605
• Cannot dispatch tasks when running outside openswoole request.
  • Docker - Service could not be created - Address in use #1743
• Less convenient to install. Roadrunner can be installed "by Shlink".
• Integration is more complex in general. A dedicated library is required (mezzio/mezzio-swoole), while roadrunner natively supports PSR-7 and a simple script does the job.
  • It's true that openswoole 22 supports PSR-7 too, but it has two problems: 1) While older versions are supported, there's no way to "just" switch to this approach. 2) I did a POC and could not get it working.
• Performance is almost the same as openswoole (although more benchmarks are still needed).

The only considerations are:

• Roadrunner logs are not exactly the same as the ones generated by mezzio/mezzio-swoole when using openswoole. It would be good to get as close as possible.
  • The main missing feature is the request ID, but it doesn't seem to be supported by roadrunner.
• It is possible to provide openswoole config via env vars, which is ignored by roadrunner. Would be good to see if something similar is possible with roadrunner. To be investigated in future if demanded.
• The docker image is currently published with two flavors. No suffix uses openswoole, and -roadunner suffix uses roadrunner.
  • In order to keep BC, publish three versions from now on: No suffix has the "default" runtime, whichever it is. Then one suffixed tag is published for every specific runtime, warrantying that runtime will be used even if default one changes over time.