Add Basic Auth and HTTPS support to Elasticsearch

[joehillen]

We use https://www.elastic.co/cloud/as-a-service for logging, so we need HTTPS and Basic Auth in order to send logs there.

[23Skidoo]

The only worry I have is that there's no warning or error when we send an Authorization header across an unencrypted connection.

[joehillen]

I'm open to suggestions there. However, most internet applications happily send Auth headers over non-TLS.

Should withElasticSearchLogger call error when there is a EsLogin but the url doesn't start with https? There would also need to be a way to override it for when you're on a trusted network or talking to localhost.

[23Skidoo]

Sounds like a good idea to me. We'd have a knob in ElasticSearchConfig with a name like esAllowAuthOverPlainHTTP or something similar.

[phadej]

What's @23Skidoo / scrive's opinion on lens, it would be great to lensify config, so adding fields won't be backwards breaking change, if there's default?

[joehillen]

@phadej Adding fields is not a backwards breaking change if your using defaultElasticSearchConfig. I don't see how using lens would make that any different. You'd still have to use defaultElasticSearchConfig if you were using lens.

@23Skidoo I've made the requested addition.

[phadej]

@joehillen it is breaking if constructor is exported. I personally dislike mentioning "don't use constructor, but defaultXXX and setters", as it easy to not notice, and quite easy to enforce.

EDIT: and with lens the API is simpler if you omit constuctor, as you don't need to export getters and setters separately, like e.g. in http-client

[joehillen]

But what does that have to do with lens?

[23Skidoo]

We can make the constructor private and move it to a Internal module. I'd prefer to avoid adding a dependency on lens.

[phadej]

@joehillen edited the previous comment, @23Skidoo field lenses can be created without dependency. (Like it's done in Cabal ;))

[joehillen]

lens seems like massive overkill for a flat 5 field config that is probably never modified.

Also, this is outside of scope of this PR.

[phadej]

It's related, as this PR forces major bump of the version. It's not biggie, but some solution would be great. And yes, the config is modified, how'd you set the server address otherwise?

[23Skidoo]

Merged, thanks!

@phadej

field lenses can be created without dependency. (Like it's done in Cabal ;))

Can you remind me how the code for that looks like?

[phadej]

Three lines:

• Lens' type alias https://github.com/haskell/cabal/blob/d23c5948ff18e19335a87aa30a98ac2aa9d72bb1/Cabal/tests/ParserHackageTests.hs#L254
• lens helper, not strictly required https://github.com/haskell/cabal/blob/d23c5948ff18e19335a87aa30a98ac2aa9d72bb1/Cabal/tests/ParserHackageTests.hs#L283
• and the example lens https://github.com/haskell/cabal/blob/d23c5948ff18e19335a87aa30a98ac2aa9d72bb1/Cabal/tests/ParserHackageTests.hs#L329

[23Skidoo]

@phadej I'm okay with adding this stuff, but I'd prefer if it lived in its own module (e.g. Backend.ElasticSearch.Lens).

[phadej]

I'll make a PR