Missing documentation and best practices for bzlmod #1715

alimoli · 2024-01-05T13:28:41Z

I tried to follow the tutorial for the migration from the legacy WORKSPACE (version 6.3.2) to bzlmod (enabled by default using version 7.0.0, the version that I am migrating to).

Considering my current environment, a monorepo composed of multiple Go projects using go-modules and docker rules to create build/push the images, I am finding it quite tricky to follow.

First of all, I have the feeling there are no "best practices" for Go projects with Bazel.

Example
Should I prefer a design where I have a MODULE.bazel for each project in the monorepo?
Or should I have one single MODULE.bazel for the entire monorepo at the WORKSPACE level (as suggested in the tutorial)?

Secondly, I am not able to find documentation to adapt gazelle with bzlmod.

Thank you in advance for your help.

The text was updated successfully, but these errors were encountered:

fmeum · 2024-01-05T13:31:46Z

The docs exist, they just aren't sufficiently discoverable: https://github.com/bazelbuild/rules_go/blob/master/docs/go/core/bzlmod.md

@tyler-french What do you think, is it time to make the Bzlmod instructions the default?

fmeum · 2024-01-05T13:33:49Z

Or should I have one single MODULE.bazel for the entire monorepo at the WORKSPACE level (as suggested in the tutorial)?

I would say that a monorepo should really have one MODULE.bazel file, just like it had one WORKSPACE file.

alimoli · 2024-01-05T14:46:16Z

Thank you for the quick answer guys! 🙏
I followed it, but I got some errors even in an "empty" project.

Version Bazel: 7.0.0 (installed via bazelisk)
Version Gazelle: 0.35.0

MODULE.bazel

module(
    name="bazel_project",
    version="1.0.0"
)

bazel_dep(name = "rules_go", version = "0.44.2")
bazel_dep(name = "gazelle", version = "0.35.0")

Errors:

> bazel run //:gazelle
WARNING: Target pattern parsing failed.
ERROR: Skipping '//:gazelle': error loading package '': Unable to find package for @@[unknown repo 'bazel_gazelle' requested from @@]//:def.bzl: The repository '@@[unknown repo 'bazel_gazelle' requested from @@]' could not be resolved: No repository visible as '@bazel_gazelle' from main repository.
ERROR: error loading package '': Unable to find package for @@[unknown repo 'bazel_gazelle' requested from @@]//:def.bzl: The repository '@@[unknown repo 'bazel_gazelle' requested from @@]' could not be resolved: No repository visible as '@bazel_gazelle' from main repository.
INFO: Elapsed time: 0.087s
INFO: 0 processes.
ERROR: Build did NOT complete successfully
ERROR: Build failed. Not running target

If I change the MODULE.bazel to:

module(
    name="bazel_project",
    version="1.0.0"
)

bazel_dep(name = "rules_go", version = "0.44.2", repo_name = "io_bazel_rules_go")
bazel_dep(name = "gazelle", version = "0.35.0", repo_name = "bazel_gazelle")

I get a different error:

>bazel run //:gazelle
INFO: Repository gazelle~0.35.0~non_module_deps~bazel_gazelle_go_repository_cache instantiated at:
  <builtin>: in <toplevel>
Repository rule go_repository_cache defined at:
  /private/var/tmp/_bazel_xxx/231abc74738b39afb97d17a62e2fa9f9/external/gazelle~0.35.0/internal/go_repository_cache.bzl:71:38: in <toplevel>
ERROR: An error occurred during the fetch of repository 'gazelle~0.35.0~non_module_deps~bazel_gazelle_go_repository_cache':
   Traceback (most recent call last):
        File "/private/var/tmp/_bazel_xxx/231abc74738b39afb97d17a62e2fa9f9/external/gazelle~0.35.0/internal/go_repository_cache.bzl", line 38, column 27, in _go_repository_cache_impl
                go_root = str(ctx.path(go_sdk_label).dirname)
Error in path: Unable to load package for @@rules_go~0.44.0~go_sdk~go_default_sdk//:ROOT: The repository '@@rules_go~0.44.0~go_sdk~go_default_sdk' could not be resolved: Repository '@@rules_go~0.44.0~go_sdk~go_default_sdk' is not defined
ERROR: <builtin>: fetching go_repository_cache rule //:gazelle~0.35.0~non_module_deps~bazel_gazelle_go_repository_cache: Traceback (most recent call last):
        File "/private/var/tmp/_bazel_xxx/231abc74738b39afb97d17a62e2fa9f9/external/gazelle~0.35.0/internal/go_repository_cache.bzl", line 38, column 27, in _go_repository_cache_impl
                go_root = str(ctx.path(go_sdk_label).dirname)
Error in path: Unable to load package for @@rules_go~0.44.0~go_sdk~go_default_sdk//:ROOT: The repository '@@rules_go~0.44.0~go_sdk~go_default_sdk' could not be resolved: Repository '@@rules_go~0.44.0~go_sdk~go_default_sdk' is not defined
ERROR: no such package '@@gazelle~0.35.0~go_deps~com_github_pmezard_go_difflib//difflib': no such package '@@gazelle~0.35.0~non_module_deps~bazel_gazelle_go_repository_cache//': Unable to load package for @@rules_go~0.44.0~go_sdk~go_default_sdk//:ROOT: The repository '@@rules_go~0.44.0~go_sdk~go_default_sdk' could not be resolved: Repository '@@rules_go~0.44.0~go_sdk~go_default_sdk' is not defined
ERROR: /private/var/tmp/_bazel_xxx/231abc74738b39afb97d17a62e2fa9f9/external/gazelle~0.35.0/cmd/gazelle/BUILD.bazel:10:11: no such package '@@gazelle~0.35.0~go_deps~com_github_pmezard_go_difflib//difflib': no such package '@@gazelle~0.35.0~non_module_deps~bazel_gazelle_go_repository_cache//': Unable to load package for @@rules_go~0.44.0~go_sdk~go_default_sdk//:ROOT: The repository '@@rules_go~0.44.0~go_sdk~go_default_sdk' could not be resolved: Repository '@@rules_go~0.44.0~go_sdk~go_default_sdk' is not defined and referenced by '@@gazelle~0.35.0//cmd/gazelle:gazelle_lib'
ERROR: Analysis of target '//:gazelle' failed; build aborted: Analysis failed
INFO: Elapsed time: 0.170s, Critical Path: 0.00s
INFO: 1 process: 1 internal.
ERROR: Build did NOT complete successfully
ERROR: Build failed. Not running target
FAILED: 
    Fetching repository @@gazelle~0.35.0~go_deps~com_github_pmezard_go_difflib; Restarting.

Context:

I have just created this public repository so you can probably find more easily the issue:
https://github.com/alimoli/bazel_project

alimoli · 2024-01-05T15:10:01Z

Related to my previous comment @fmeum, it seems the error comes from the rules_go version.
Setting 0.44.0 instead of 0.44.2 (the latest one) works.
However, this works only if I use this syntax:

bazel_dep(name = "rules_go", version = "0.44.0", repo_name = "io_bazel_rules_go")
bazel_dep(name = "gazelle", version = "0.35.0", repo_name = "bazel_gazelle")

So, I am wondering about this part:

If you have WORKSPACE dependencies that reference rules_go and/or Gazelle, you can still use the legacy repository names for the two repositories:

Am I in this condition? It is not clear to me :/ My WORKSPACE is completely empty.

For all these issues, I added the comments in the repo here:
https://github.com/alimoli/bazel_project

fmeum · 2024-01-05T15:58:16Z

You are affected by this bug: bazelbuild/bazel#20721

Could you try again with Bazel 7.0.1rc1?

alimoli · 2024-01-05T16:08:11Z

Same error @fmeum:

> bazel run //:gazelle
2024/01/05 17:05:12 Downloading https://releases.bazel.build/7.0.1/rc1/bazel-7.0.1rc1-darwin-arm64...
Downloading: 51 MB out of 51 MB (100%) 
Extracting Bazel installation...
Starting local Bazel server and connecting to it...
WARNING: Target pattern parsing failed.
ERROR: Skipping '//:gazelle': error loading package '': Unable to find package for @@[unknown repo 'bazel_gazelle' requested from @@]//:def.bzl: The repository '@@[unknown repo 'bazel_gazelle' requested from @@]' could not be resolved: No repository visible as '@bazel_gazelle' from main repository.
ERROR: error loading package '': Unable to find package for @@[unknown repo 'bazel_gazelle' requested from @@]//:def.bzl: The repository '@@[unknown repo 'bazel_gazelle' requested from @@]' could not be resolved: No repository visible as '@bazel_gazelle' from main repository.
INFO: Elapsed time: 8.562s
INFO: 0 processes.
ERROR: Build did NOT complete successfully
ERROR: Build failed. Not running target

Both for:

bazel_dep(name = "rules_go", version = "0.44.2")
bazel_dep(name = "gazelle", version = "0.35.0")

bazel_dep(name = "rules_go", version = "0.44.0")
bazel_dep(name = "gazelle", version = "0.35.0")

bazel_dep(name = "rules_go", version = "0.44.2", repo_name = "io_bazel_rules_go")
bazel_dep(name = "gazelle", version = "0.35.0", repo_name = "bazel_gazelle")

Same like before. It still works only with:

bazel_dep(name = "rules_go", version = "0.44.0", repo_name = "io_bazel_rules_go")
bazel_dep(name = "gazelle", version = "0.35.0", repo_name = "bazel_gazelle")

fmeum · 2024-01-05T16:48:22Z

That error means that you need to update the load in your top-level BUILD file to be from gazelle rather than bazel_gazelle. You can of course keep using the old names with repo_name.

alimoli · 2024-01-08T08:15:28Z

Thank you @fmeum for the fix.
It worked and now I am able to use gazelle with the right naming.
Now, I am wondering why bazel is not able to build despite the successful gazelle build.

bazel run //:gazelle
INFO: Analyzed target //:gazelle (118 packages loaded, 11413 targets configured).
INFO: Found 1 target...
Target //:gazelle up-to-date:
  bazel-bin/gazelle-runner.bash
  bazel-bin/gazelle
INFO: Elapsed time: 1.309s, Critical Path: 0.01s
INFO: 1 process: 1 internal.
INFO: Build completed successfully, 1 total action
INFO: Running command line: bazel-bin/gazelle

bazel build //...                     
ERROR: no such package '@@[unknown repo 'com_github_mitchellh_mapstructure' requested from @@]//': The repository '@@[unknown repo 'com_github_mitchellh_mapstructure' requested from @@]' could not be resolved: No repository visible as '@com_github_mitchellh_mapstructure' from main repository
ERROR: /Users/xxx/bazel_project/a/BUILD.bazel:3:11: no such package '@@[unknown repo 'com_github_mitchellh_mapstructure' requested from @@]//': The repository '@@[unknown repo 'com_github_mitchellh_mapstructure' requested from @@]' could not be resolved: No repository visible as '@com_github_mitchellh_mapstructure' from main repository and referenced by '//a:a'
ERROR: Analysis of target '//a:a' failed; build aborted: Analysis failed
INFO: Elapsed time: 0.272s, Critical Path: 0.00s
INFO: 1 process: 1 internal.
ERROR: Build did NOT complete successfully

Is it caused by:

# gazelle:prefix bazel_project

?

Or something related to this?

I have updated the repository in case you want to take a look. 🙏

fmeum · 2024-01-09T20:04:56Z

That failure is expected, you aren't declaring any external dependencies. That is what the go_deps extension is for, see https://github.com/bazelbuild/rules_go/blob/master/docs/go/core/bzlmod.md#external-dependencies.

This let's us call `bazel build ...` from the packages directory or the root directory. Since we have a monorepo, a single MODULE.bazel file should be enough anyway. See, bazel-contrib/bazel-gazelle#1715 (comment) CMK-17767 Change-Id: I86603b70f8f9203242b0e40afb206b74e4f6abeb

aran mentioned this issue Feb 9, 2024

Support for Bzlmod in a monorepo #1658

Open

fmeum closed this as not planned Won't fix, can't repro, duplicate, stale Apr 24, 2024

Provide feedback

Saved searches

Use saved searches to filter your results more quickly

Missing documentation and best practices for bzlmod #1715

Missing documentation and best practices for bzlmod #1715

alimoli commented Jan 5, 2024

fmeum commented Jan 5, 2024

fmeum commented Jan 5, 2024

alimoli commented Jan 5, 2024 •

edited

Loading

alimoli commented Jan 5, 2024 •

edited

Loading

fmeum commented Jan 5, 2024

alimoli commented Jan 5, 2024

fmeum commented Jan 5, 2024

alimoli commented Jan 8, 2024 •

edited

Loading

fmeum commented Jan 9, 2024

Missing documentation and best practices for bzlmod #1715

Missing documentation and best practices for bzlmod #1715

Comments

alimoli commented Jan 5, 2024

fmeum commented Jan 5, 2024

fmeum commented Jan 5, 2024

alimoli commented Jan 5, 2024 • edited Loading

alimoli commented Jan 5, 2024 • edited Loading

fmeum commented Jan 5, 2024

alimoli commented Jan 5, 2024

fmeum commented Jan 5, 2024

alimoli commented Jan 8, 2024 • edited Loading

fmeum commented Jan 9, 2024

alimoli commented Jan 5, 2024 •

edited

Loading

alimoli commented Jan 5, 2024 •

edited

Loading

alimoli commented Jan 8, 2024 •

edited

Loading