Read serialized qos profiles out of the metadata

[emersonknapp]

Part of #125

This PR introduces the ability to read the new field offered_qos_profiles out of a bag metadata. This required making a way to pass version information to sub-structs of BagMetadata so that backwards compatibility can be maintained.

[piraka9011]

This is pretty interesting, how does it work for future changes to the metadata? Do we just add a layer on top of decode?

[emersonknapp]

You just add if blocks for data added in new versions. That's the way that I have historically seen this done for similar data format parsing.

And if you remove fields you send up making it a version range for reading

[thomas-moulard]

PR LGTM, but this versioning approach is going to explode pretty soon if we continue doing active development. I'd suggest to spend some time post-release thinking about what we should be doing (cough Protobuf cough cough).

[thomas-moulard]

Actually LGTM'ing the PR

[piraka9011]

Pending Thomas comments and Green CI

[emersonknapp]

• Linux
• Linux-aarch64
• macOS
• Windows

[jacobperron]

@emersonknapp FYI, we're having a windows build issue that just started happening. I cleared a build from the queue and edited your comment to point to the right build number, but I think you might hit the same unrelated build failure in resource_retriever.

Edit: related issue ros/resource_retriever#38

[emersonknapp]

Thanks for the heads up!

[emersonknapp]

Running CI again before merging since a few minor changes have gone into this and a lot has gone into the upstream

• Linux
• Linux-aarch64
• macOS
• Windows

Retrying windows

[emersonknapp]

The test failures are clearly unrelated, having to do with typesupport for connext and cyclone, on windows, in the last two runs. We need to fix that, but I'm going to merge this change to unblock the followup work.