[ci] refactor auth out of copy_files

[andrew-anyscale]

For the Wanda version of building each Ray Image, we want to selectively upload to DockerHub only in certain postsubmit cases. Rather than calling on 'buildkite:copy_files --destination docker_login' separately, this refactor pushes the auth setup to a central library that can be called on certain conditions.

Without this, logic would need to be pushed into the Rayci step itself, since current login is gated on a per-Pipeline-ID basis.

Topic: auth-refactor
Relative: multiplat-support
Labels: draft
Signed-off-by: andrew andrew@anyscale.com

[andrew-anyscale]

Reviews in this chain:
└#60614 [ci] refactor auth out of copy_files

[andrew-anyscale]

#	head	base	diff	date	summary
0	68188ccb	2195731c	diff	Jan 30 10:19 AM	6 files changed, 103 insertions(+), 48 deletions(-)
1	7452f4cf	2195731c	diff	Jan 30 10:46 AM	1 file changed, 23 insertions(+), 8 deletions(-)
2	54061a8c	e8e58b5f	rebase	Jan 30 10:58 AM	0 files changed
3	9fc08d89	26fe1233	diff	Jan 30 10:59 AM	0 files changed
4	aa87d9de	26fe1233	diff	Jan 30 12:22 PM	1 file changed, 2 insertions(+), 1 deletion(-)
5	c6a71b7e	60f859bc	rebase	Jan 30 13:28 PM	0 files changed
6	86e7fb92	557b8d7e	rebase	Jan 30 13:31 PM	0 files changed
7	c77beb56	aa0695a8	diff	Jan 30 13:58 PM	1 file changed, 5 deletions(-)
8	c77beb56	aa0695a8	diff	Jan 30 13:59 PM	0 files changed
9	ecb0349d	2b490725	diff	Jan 30 14:21 PM	2 files changed, 17 insertions(+), 3 deletions(-)
10	89c38347	44aa52e6	rebase	Jan 30 15:13 PM	0 files changed
11	44f98a48	3e40294d	diff	Jan 30 17:26 PM	0 files changed

[gemini-code-assist]

Code Review

This pull request refactors authentication logic into a new centralized library, ci/ray_ci/rayci_auth.py, which is a great improvement for code organization and reusability. The new implementation for Docker Hub login also enhances security by using --password-stdin, preventing password exposure in the process list. My review focuses on the new rayci_auth.py file, offering suggestions to improve its robustness, maintainability, and error handling.

[cursor]

Cursor Bugbot has reviewed your changes and found 1 potential issue.

[aslonnie]

why is this in draft? is this ready for review?

[aslonnie]

these are a lot of mocks.. we probably need to talk about this in person..