Allow setting timeout for cargo-bazel. (#3485)

This PR introduces `CARGO_BAZEL_TIMEOUT` env variable to set timeout
value for `cargo-bazel` invocation.

---------

Co-authored-by: Daniel Wagner-Hall <[email protected]>

Author: sardok

crate_universe/extensions.bzl

@@ -1377,6 +1377,7 @@ Environment Variables:
 | `CARGO_BAZEL_ISOLATED` | An authoritative flag as to whether or not the `CARGO_HOME` environment variable should be isolated from the host configuration |
 | `CARGO_BAZEL_REPIN` | An indicator that the dependencies represented by the rule should be regenerated. `REPIN` may also be used. See [Repinning / Updating Dependencies](crate_universe_workspace.html#repinning--updating-dependencies) for more details. |
 | `CARGO_BAZEL_REPIN_ONLY` | A comma-delimited allowlist for rules to execute repinning. Can be useful if multiple instances of the repository rule are used in a Bazel workspace, but repinning should be limited to one of them. |
+| `CARGO_BAZEL_TIMEOUT` | An integer value to override the default timeout setting when running the cargo-bazel binary. This value must be in seconds. |
 
 """,
     implementation = _crate_impl,

crate_universe/private/common_utils.bzl

@@ -9,6 +9,7 @@ get_host_triple = _get_host_triple
 CARGO_BAZEL_ISOLATED = "CARGO_BAZEL_ISOLATED"
 CARGO_BAZEL_REPIN = "CARGO_BAZEL_REPIN"
 CARGO_BAZEL_DEBUG = "CARGO_BAZEL_DEBUG"
+CARGO_BAZEL_TIMEOUT = "CARGO_BAZEL_TIMEOUT"
 REPIN = "REPIN"
 
 CARGO_BAZEL_REPIN_ONLY = "CARGO_BAZEL_REPIN_ONLY"
@@ -45,10 +46,15 @@ def execute(repository_ctx, args, env = {}, allow_fail = False, quiet = True):
     if repository_ctx.os.environ.get(CARGO_BAZEL_DEBUG, None):
         quiet = False
 
+    exec_kwargs = dict(environment = env, quiet = quiet)
+
+    timeout = repository_ctx.os.environ.get(CARGO_BAZEL_TIMEOUT, None)
+    if timeout:
+        exec_kwargs.update(timeout = int(timeout))
+
     result = repository_ctx.execute(
         args,
-        environment = env,
-        quiet = quiet,
+        **exec_kwargs
     )
 
     if result.return_code and not allow_fail:

crate_universe/private/crates_repository.bzl

@@ -161,6 +161,7 @@ Environment Variables:
 | `CARGO_BAZEL_ISOLATED` | An authoritative flag as to whether or not the `CARGO_HOME` environment variable should be isolated from the host configuration |
 | `CARGO_BAZEL_REPIN` | An indicator that the dependencies represented by the rule should be regenerated. `REPIN` may also be used. See [Repinning / Updating Dependencies](#repinning--updating-dependencies) for more details. |
 | `CARGO_BAZEL_REPIN_ONLY` | A comma-delimited allowlist for rules to execute repinning. Can be useful if multiple instances of the repository rule are used in a Bazel workspace, but repinning should be limited to one of them. |
+| `CARGO_BAZEL_TIMEOUT` | An integer value to override the default timeout setting when running the cargo-bazel binary. This value must be in seconds. |
 
 Example:
 

crate_universe/private/generate_utils.bzl

@@ -4,6 +4,7 @@ load(
     ":common_utils.bzl",
     "CARGO_BAZEL_DEBUG",
     "CARGO_BAZEL_ISOLATED",
+    "CARGO_BAZEL_TIMEOUT",
     "REPIN_ALLOWLIST_ENV_VAR",
     "REPIN_ENV_VARS",
     "parse_alias_rule",
@@ -21,6 +22,7 @@ CRATES_REPOSITORY_ENVIRON = GENERATOR_ENV_VARS + REPIN_ENV_VARS + [
     REPIN_ALLOWLIST_ENV_VAR,
     CARGO_BAZEL_ISOLATED,
     CARGO_BAZEL_DEBUG,
+    CARGO_BAZEL_TIMEOUT,
 ]
 
 def get_generator(repository_ctx, host_triple):