[ls-apis] check that only omicron-sled-agent depends on nexus-lockstep-client

[sunshowers]

Sled Agent depends on nexus-lockstep-client via RSS, and we now ensure that nothing else that's part of one of the deployment units depends on it. (We don't treat omdb as part of a deployment unit because it doesn't participate in upgrade in the typical sense.)

Also add an expectorate test for the output of ls-apis check, similar to the existing one for ls-apis apis.

Closes #9057.

[sunshowers]

Testing notes

With this change:

diff --git a/dev-tools/ls-apis/api-manifest.toml b/dev-tools/ls-apis/api-manifest.toml
index 3143acd089..56556ef748 100644
--- a/dev-tools/ls-apis/api-manifest.toml
+++ b/dev-tools/ls-apis/api-manifest.toml
@@ -351,7 +351,8 @@
 # `packages` arrays in the deployment_units table above) are allowed to use this
 # API. ls-apis check will error out if the list of consumers is incorrect.
 consumers = [
-     { name = "omicron-sled-agent", reason = "RSS uses it, which isn't part of upgrade" },
+     #{ name = "omicron-sled-agent", reason = "RSS uses it, which isn't part of upgrade" },
+     { name = "omicron-nexus", reason = "Nexus uses it, which isn't part of upgrade" },
 ]
 
 [[apis]]

ls-apis check has this output:

https://gist.github.com/sunshowers/787f58ef7a34458ffdce430cb7b10129

ls-apis apis has this output:

https://gist.github.com/sunshowers/0ddf0da4ecb18d7c495abfd5ab594a85

[davepacheco]

Do you have examples of this problem? I just want to make sure these messages are clear and actionable to people that might run into this.

[sunshowers]

For example, if you say

restricted_to_consumers = [
     { name = "omicron-foobar", reason = "..." },
]

Then, at load-time we error out with:

Error: api nexus-lockstep-client specifies unknown consumer: omicron-foobar (with expected reason: ...)

This panic asserts that the load-time check has already been performed.

[davepacheco]

Maybe add "this is a bug" or something, if the expectation is that they'd never see this message?

[davepacheco]

Thoughts on: Unrestricted, meaning "this API has no configured restrictions on which consumers can use it"?

[davepacheco]

Thanks!

[davepacheco]

Maybe add "this is a bug" or something, if the expectation is that they'd never see this message?