add support for Elasticsearch 8, default to running that for local tests, and test both 7 and 8 in CI

[philvarner]

Related Issue(s):

• Support for Elasticsearch 8 #49

Description:

• pin elasticsearch and elasticsearch-dsl libraries
• add header for ES 8 that provides backwards compat with 7.
• update CI tests to run against Elasticsearch 7 and 8

PR Checklist:

• Code is formatted and linted (run pre-commit run --all-files)
• Tests pass (run make test)
• Documentation has been updated to reflect changes, if applicable, and docs build successfully (run make docs)
• Changes are added to the changelog

[philvarner]

this doesn't do anything. name is not a property of default.

[philvarner]

For some reason, the tests can't connect to ES 8 when running in CI. 🤷🏻 Worked fine locally.

[jonhealy1]

So weird

[philvarner]

Ah, so apparently it didn't work fine locally -- I think I still had a 7.x instance running.

The underlying issue is that security is enabled by default for 8.x, so that means (1) the elastic user has a password that gets generated at first startup and (2) TLS is required and has a self-signed cert. I've only found instructions on how to run this manually (e.g., "run the image and copy the password to your secure notes") and now how to do it in an automated way.

I think I'm going to merge these changes and only run against 7.x, and then at some point later we can get it running with 8.

[jonhealy1]

I guess make an issue