Add configurable limits for number of builds allowed under a namespace

We also support that limit being increased automatically once a successful billing charge has gone through

data/database.py

@@ -439,6 +439,8 @@ class User(BaseModel):
   company = CharField(null=True)
   location = CharField(null=True)
 
+  maximum_queued_builds_count = IntegerField(null=True)
+
   def delete_instance(self, recursive=False, delete_nullable=False):
     # If we are deleting a robot account, only execute the subset of queries necessary.
     if self.robot:

data/migrations/versions/152bb29a1bb3_add_maximum_build_queue_count_setting_.py

@@ -0,0 +1,26 @@
+"""Add maximum build queue count setting to user table
+
+Revision ID: 152bb29a1bb3
+Revises: 7367229b38d9
+Create Date: 2018-02-20 13:34:34.902415
+
+"""
+
+# revision identifiers, used by Alembic.
+revision = '152bb29a1bb3'
+down_revision = 'cbc8177760d9'
+
+from alembic import op
+import sqlalchemy as sa
+from sqlalchemy.dialects import mysql
+
+def upgrade(tables):
+    # ### commands auto generated by Alembic - please adjust! ###
+    op.add_column('user', sa.Column('maximum_queued_builds_count', sa.Integer(), nullable=True))
+    # ### end Alembic commands ###
+
+
+def downgrade(tables):
+    # ### commands auto generated by Alembic - please adjust! ###
+    op.drop_column('user', 'maximum_queued_builds_count')
+    # ### end Alembic commands ###

data/model/user.py

@@ -80,7 +80,9 @@ def create_user_noverify(username, email, email_required=True, prompts=tuple()):
 
   try:
     default_expr_s = _convert_to_s(config.app_config['DEFAULT_TAG_EXPIRATION'])
-    new_user = User.create(username=username, email=email, removed_tag_expiration_s=default_expr_s)
+    default_max_builds = config.app_config.get('DEFAULT_NAMESPACE_MAXIMUM_BUILD_COUNT')
+    new_user = User.create(username=username, email=email, removed_tag_expiration_s=default_expr_s,
+                           maximum_queued_builds_count=default_max_builds)
     for prompt in prompts:
       create_user_prompt(new_user, prompt)
 
@@ -88,6 +90,14 @@ def create_user_noverify(username, email, email_required=True, prompts=tuple()):
   except Exception as ex:
     raise DataModelException(ex.message)
 
+def increase_maximum_build_count(user, maximum_queued_builds_count):
+  """ Increases the maximum number of allowed builds on the namespace, if greater than that
+      already present.
+  """
+  if (user.maximum_queued_builds_count is not None and
+      maximum_queued_builds_count > user.maximum_queued_builds_count):
+    user.maximum_queued_builds_count = maximum_queued_builds_count
+    user.save()
 
 def is_username_unique(test_username):
   try:

data/queue.py

@@ -74,6 +74,19 @@ class WorkQueue(object):
             ._available_jobs(now, name_match_query)
             .where(~(QueueItem.queue_name << running_query)))
 
+  def num_available_jobs(self, canonical_name_list):
+    """
+    Returns the number of available queue items with a given prefix.
+    """
+    def strip_slash(name):
+      return name.lstrip('/')
+    canonical_name_list = map(strip_slash, canonical_name_list)
+
+    available = self._available_jobs(datetime.utcnow(),
+                                     '/'.join([self._queue_name] + canonical_name_list) + '%')
+
+    return available.count()
+
   def num_available_jobs_between(self, available_min_time, available_max_time, canonical_name_list):
     """
     Returns the number of available queue items with a given prefix, between the two provided times.