Bazel not running flutter correctly - flutter

Question

I'm trying to execute a flutter command using bazel. This is my BUILD.bazel file:
genrule(
name = "flutter_build",
srcs = [
"//:root_filegroup"
],
outs = ["out.txt"],
cmd = "flutter build ipa --export-method development"
)
The command flutter build ipa --export-method development works perfectly if I run it directly in my iterm, but for some reason the same command in bazel returns a permission error:
Flutter failed to open a file at "/Users/rlanhe/tools/flutter/flutter/bin/cache/lockfile".
Please ensure that the SDK and/or project is installed in a location that has read/write permissions for the current user.
Try running:
sudo chown -R $(whoami) /Users/rlanhe/tools/flutter/flutter/bin/cache/lockfile
Well, doesn't make sense to me, since that folder already have correct permission and I'm able to run the command outside bazel.

Answer 1

Integrating Flutter/Dart and Bazel is likely a large amount of work.
There's an issue here about it:
https://github.com/flutter/flutter/issues/19680
And it looks like there are some dart rules here:
https://github.com/cbracken/rules_dart
The immediate issue you're running into is that Bazel runs each action (i.e. build step) in a sandbox, so unless an input to the action is declared, it's not going to be in the sandbox. You can maybe get further by adding tags = ["no-sandbox"] to the genrule, (see https://bazel.build/reference/be/common-definitions#common.tags).
This is essentially running one build system inside another, and this isn't going get the caching and incrementality benefits of Bazel, because Bazel has no insight into what happens inside the genrule. Unless you have some higher-level plans to integrate this into a larger repository that uses Bazel, there isn't much benefit here compared to running flutter directly or in a shell script.