Consider switching CI to Azure Pipelines

[Manishearth]

rustc has moved to it, and it seems overall nicer. It supports all three OSes, and it also supports better pipelining. So, for example, one can build clippy first, and then parallelize the integration tests based on a single clippy build (instead of having ten integration test workers all build clippy). This should be faster, and we might benefit from the Rust org's azure builders, though we'd have to check with the infra team on that (@pietro?).

thoughts? @phansch @flip1995 @oli-obk @yaahc

[yaahc]

👍

I know tracing is using azure and I've only heard positive things. I bet this is a win.

[phansch]

Seems like a good idea 👍 I can't come up with anything that our current setup has that Azure doesn't have.

Some things that are currently travis specific:

• .github/deploy.sh is using some TRAVIS_ env variables
• ci/base-tests.sh uses TRAVIS_OS_NAME
• We have two encrypted variables in the Travis config UI, which I don't know what they are used for
• Our bors setup needs to be updated as well, I believe

[flip1995]

Sounds good. Especially the "supports all three OSes" part, since we tried pretty often to use the travis windows build, without success. #3418 #4004 #4320 #4324 #3306 #3484 #3486 ... (way too often 😄)

We have two encrypted variables in the Travis config UI, which I don't know what they are used for

This type of secret key is normally used for ssh deployment from travis. We're using them here:

rust-clippy/.github/deploy.sh

Lines 60 to 65 in 1366629

	ENCRYPTION_LABEL=e3a2d77100be
	ENCRYPTED_KEY_VAR="encrypted_${ENCRYPTION_LABEL}_key"
	ENCRYPTED_IV_VAR="encrypted_${ENCRYPTION_LABEL}_iv"
	ENCRYPTED_KEY=${!ENCRYPTED_KEY_VAR}
	ENCRYPTED_IV=${!ENCRYPTED_IV_VAR}
	openssl aes-256-cbc -K "$ENCRYPTED_KEY" -iv "$ENCRYPTED_IV" -in .github/deploy_key.enc -out .github/deploy_key -d

[mati865]

Small Rust projects mostly use Github Actions now but I don't know if it'd suffice for Clippy.

[flip1995]

Even though I think GitHub Actions is a good CI/CD tool, I don't think that it is quite there yet, to support a project like Clippy. So I'd vote for Azure, if at all possible.

[mati865]

FYI https://blog.rust-lang.org/inside-rust/2019/11/14/evaluating-github-actions.html

[Manishearth]

Yep, and when I asked infra folks they also suggested using Actions (because of the then-not-public switch linked above)