src/main/java/com/google/devtools/build/docgen/templates/attributes/common/tags.html

<p>
  <code>List of arbitrary text tags.  Tags may be any valid string; default is
  the empty list; <a href="#configurable-attributes">nonconfigurable</a></code>
</p>

<p>
  <i>Tags</i> can be used on any rule. <i>Tags</i> on test and
  <code>test_suite</code> rules are useful for categorizing the tests.
  <i>Tags</i> on non-test rules are used to control sandboxed execution of
  <code>genrule</code>s and

<a href="/versions/{{ site.version }}/skylark/index.html">Starlark</a>
  actions, and for parsing by humans and/or external tools.
</p>

<p>
  Bazel modifies the behavior of its sandboxing code if it finds the following
  keywords in the <code>tags</code> attribute of any test rule or
  <code>genrule</code>, or the keys of <code>execution_requirements</code> for
  any Starlark action.
</p>

<ul>
  <li><code>no-sandbox</code> keyword results in the action or test never being
    sandboxed; it can still be cached or run remotely - use <code>no-cache</code>
    or <code>no-remote</code> to prevent either or both of those.
  </li>

  <li><code>no-cache</code> keyword results in the action or test never being
    cached (remotely or locally)
  </li>

  <li><code>no-remote-cache</code> keyword results in the action or test never being
    cached remotely (but it may be cached locally; it may also be executed remotely).
    Note: for the purposes of this tag, the disk-cache is considered a local cache, whereas
    the http and gRPC caches are considered remote.
    If a combined cache is specified (i.e. a cache with local and remote components),
    it's treated as a remote cache and disabled entirely.
  </li>

  <li><code>no-remote-exec</code> keyword results in the action or test never being
    executed remotely (but it may be cached remotely).
  </li>

  <li><code>no-remote</code> keyword prevents the action or test from being executed remotely
    or cached remotely. This is equivalent to using both no-remote-cache and no-remote-exec.
  </li>

  <li><code>local</code> keyword precludes the action or test from being remotely cached,
    remotely executed, or run inside the sandbox.
    For genrules and tests, marking the rule with the <code>local = True</code>
    attribute has the same effect.
  </li>

  <li><code>requires-network</code> keyword allows access to the external
    network from inside the sandbox.  This tag only has an effect if sandboxing
    is enabled.
  </li>

  <li><code>block-network</code> keyword blocks access to the external
    network from inside the sandbox. In this case, only communication
    with localhost is allowed. This tag only has an effect if sandboxing is
    enabled.
  </li>

  <li><code>requires-fakeroot</code> runs the test or action as uid and gid 0 (i.e., the root
    user). This is only supported on Linux. This tag takes precedence over the
    <code class='flag'>--sandbox_fake_username</code> command-line option.
  </li>
</ul>

<p>
  <i>Tags</i> on tests are generally used to annotate a test's role in your
  debug and release process.  Typically, tags are most useful for C++ and Python
  tests, which lack any runtime annotation ability.  The use of tags and size
  elements gives flexibility in assembling suites of tests based around codebase
  check-in policy.
</p>

<p>
  Bazel modifies test running behavior if it finds the following keywords in the
  <code>tags</code> attribute of the test rule:
</p>

<ul>
  <li><code>exclusive</code> will force the test to be run in the
    &quot;exclusive&quot; mode, ensuring that no other tests are running at the
    same time. Such tests will be executed in serial fashion after all build
    activity and non-exclusive tests have been completed. They will also always
    run locally and thus without sandboxing.
  </li>

  <li><code>manual</code> keyword will exclude the target from expansion of target pattern wildcards
    (<code>...</code>, <code>:*</code>, <code>:all</code>, etc.) and <code>test_suite</code> rules
    which do not list the test explicitly when computing the set of top-level targets to build/run
    for the <code>build</code>, <code>test</code>, and <code>coverage</code> commands. It does not
    affect target wildcard or test suite expansion in other contexts, including the
    <code>query</code> command. Note that <code>manual</code> does not imply that a target should
    not be built/run automatically by continuous build/test systems. For example, it may be
    desirable to exclude a target from <code>bazel test ...</code> because it requires specific
    Bazel flags, but still have it included in properly-configured presubmit or continuous test
    runs.

      </li>

  <li><code>external</code> keyword will force test to be unconditionally
    executed (regardless of <code class='flag'>--cache_test_results</code>
    value).
  </li>
</ul>

See <a href="../test-encyclopedia.html#tag-conventions">Tag Conventions</a> in the
Test Encyclopedia for more conventions on tags attached to test rules.