Build: ability to cancel a running build from dashboard

readthedocs/builds/migrations/0041_track_task_id.py

@@ -0,0 +1,18 @@
+# Generated by Django 3.2.11 on 2022-01-26 20:10
+
+from django.db import migrations, models
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('builds', '0040_remove_old_jsonfields'),
+    ]
+
+    operations = [
+        migrations.AddField(
+            model_name='build',
+            name='task_id',
+            field=models.CharField(blank=True, max_length=36, null=True, verbose_name='Celery task id'),
+        ),
+    ]

readthedocs/builds/models.py

@@ -682,6 +682,13 @@ class Build(models.Model):
         help_text='Build steps stored outside the database.',
     )
 
+    task_id = models.CharField(
+        _('Celery task id'),
+        max_length=36,
+        null=True,
+        blank=True,
+    )
+
     # Managers
     objects = BuildQuerySet.as_manager()
     # Only include BRANCH, TAG, UNKNOWN type Version builds.

readthedocs/builds/views.py

@@ -1,5 +1,7 @@
 """Views for builds app."""
 
+import signal
+
 import structlog
 import textwrap
 from urllib.parse import urlparse
@@ -14,12 +16,15 @@
 from django.views.generic import DetailView, ListView
 from requests.utils import quote
 
+from readthedocs.builds.constants import BUILD_STATE_TRIGGERED, BUILD_STATE_FINISHED
 from readthedocs.builds.filters import BuildListFilter
 from readthedocs.builds.models import Build, Version
 from readthedocs.core.permissions import AdminPermission
 from readthedocs.core.utils import trigger_build
-from readthedocs.doc_builder.exceptions import BuildAppError
+from readthedocs.doc_builder.exceptions import BuildAppError, BuildCancelled
 from readthedocs.projects.models import Project
+from readthedocs.worker import app
+
 
 log = structlog.get_logger(__name__)
 
@@ -148,6 +153,46 @@ class BuildDetail(BuildBase, DetailView):
 
     pk_url_kwarg = 'build_pk'
 
+    @method_decorator(login_required)
+    def post(self, request, project_slug, build_pk):
+        project = get_object_or_404(Project, slug=project_slug)
+        build = get_object_or_404(Build, pk=build_pk)
+
+        if not AdminPermission.is_admin(request.user, project):
+            return HttpResponseForbidden()
+
+        # NOTE: `terminate=True` is required for the child to attend our call
+        # immediately when it's running the build. Otherwise, it finishes the
+        # task. However, to revoke a task that has not started yet, we don't
+        # need it.
+        if build.state == BUILD_STATE_TRIGGERED:
+            # Since the task won't be executed at all, we need to update the
+            # Build object here.
+            terminate = False
+            build.state = BUILD_STATE_FINISHED
+            build.success = False
+            build.error = BuildCancelled.message
+            build.length = 0
+            build.save()
+        else:
+            # In this case, we left the update of the Build object to the task
+            # itself to be executed in the `on_failure` handler.
+            terminate = True
+
+        log.warning(
+            'Canceling build.',
+            project_slug=project.slug,
+            version_slug=build.version.slug,
+            build_id=build.pk,
+            build_task_id=build.task_id,
+            terminate=terminate,
+        )
+        app.control.revoke(build.task_id, signal=signal.SIGINT, terminate=terminate)
+
+        return HttpResponseRedirect(
+            reverse('builds_detail', args=[project.slug, build.pk]),
+        )
+
     def get_context_data(self, **kwargs):
         context = super().get_context_data(**kwargs)
         context['project'] = self.project

readthedocs/core/utils/__init__.py

@@ -229,7 +229,18 @@ def trigger_build(project, version=None, commit=None):
         # Build was skipped
         return (None, None)
 
-    return (update_docs_task.apply_async(), build)
+    task = update_docs_task.apply_async()
+
+    # FIXME: I'm using `isinstance` here because I wasn't able to mock this
+    # properly when running tests and it fails when trying to save a
+    # `mock.Mock` object in the database.
+    #
+    # Store the task_id in the build object to be able to cancel it later.
+    if isinstance(task.id, (str, int)):
+        build.task_id = task.id
+        build.save()
+
+    return task, build
 
 
 def send_email(

readthedocs/doc_builder/exceptions.py

@@ -59,6 +59,10 @@ class DuplicatedBuildError(BuildUserError):
     status = BUILD_STATUS_DUPLICATED
 
 
+class BuildCancelled(BuildUserError):
+    message = gettext_noop('Build cancelled by user.')
+
+
 class MkDocsYAMLParseError(BuildUserError):
     GENERIC_WITH_PARSE_EXCEPTION = gettext_noop(
         'Problem parsing MkDocs YAML configuration. {exception}',

readthedocs/projects/tasks/builds.py

@@ -52,6 +52,7 @@
     BuildUserError,
     BuildMaxConcurrencyError,
     DuplicatedBuildError,
+    BuildCancelled,
     ProjectBuildsSkippedError,
     YAMLParseError,
     MkDocsYAMLParseError,
@@ -240,6 +241,7 @@ class UpdateDocsTask(SyncRepositoryMixin, Task):
         ProjectBuildsSkippedError,
         ConfigError,
         YAMLParseError,
+        BuildCancelled,
         BuildUserError,
         RepositoryError,
         MkDocsYAMLParseError,
@@ -248,6 +250,7 @@ class UpdateDocsTask(SyncRepositoryMixin, Task):
 
     # Do not send notifications on failure builds for these exceptions.
     exceptions_without_notifications = (
+        BuildCancelled,
         DuplicatedBuildError,
         ProjectBuildsSkippedError,
     )
@@ -265,10 +268,16 @@ def _setup_sigterm(self):
         def sigterm_received(*args, **kwargs):
             log.warning('SIGTERM received. Waiting for build to stop gracefully after it finishes.')
 
+        def sigint_received(*args, **kwargs):
+            log.warning('SIGINT received. Canceling the build running.')
+            raise BuildCancelled
+
         # Do not send the SIGTERM signal to children (pip is automatically killed when
         # receives SIGTERM and make the build to fail one command and stop build)
         signal.signal(signal.SIGTERM, sigterm_received)
 
+        signal.signal(signal.SIGINT, sigint_received)
+
     def _check_concurrency_limit(self):
         try:
             response = api_v2.build.concurrent.get(project__slug=self.data.project.slug)

readthedocs/templates/builds/build_detail.html

@@ -30,6 +30,13 @@
 {% block content %}
   <div class="build build-detail" id="build-detail">
 
+    {% if build.state != "finished" and request.user|is_admin:project %}
+    <form method="post" action="{% url "builds_detail" build.version.project.slug build.pk %}">
+      {% csrf_token %}
+      <input type="submit" value="{% trans "Cancel build" %}">
+    </form>
+    {% endif %}
+
     <!-- Build meta data -->
     <ul class="build-meta">
       <div data-bind="visible: finished()">