1 files changed, 85 insertions, 0 deletions
diff --git a/taskcluster/taskgraph/util/seta.py b/taskcluster/taskgraph/util/seta.py
new file mode 100644
index 000000000..a0cd30675
--- /dev/null
+++ b/taskcluster/taskgraph/util/seta.py
@@ -0,0 +1,85 @@
+import json
+import logging
+import requests
+from redo import retry
+from requests import exceptions
+
+logger = logging.getLogger(__name__)
+headers = {
+    'User-Agent': 'TaskCluster'
+}
+
+# It's a list of project name which SETA is useful on
+SETA_PROJECTS = ['mozilla-inbound', 'autoland']
+SETA_ENDPOINT = "https://seta.herokuapp.com/data/setadetails/?branch=%s"
+
+
+class SETA(object):
+    """
+    Interface to the SETA service, which defines low-value tasks that can be optimized out
+    of the taskgraph.
+    """
+    def __init__(self):
+        # cached low value tasks, by project
+        self.low_value_tasks = {}
+
+    def query_low_value_tasks(self, project):
+        # Request the set of low value tasks from the SETA service.  Low value tasks will be
+        # optimized out of the task graph.
+        if project not in SETA_PROJECTS:
+            logger.debug("SETA is not enabled for project `{}`".format(project))
+            return []
+
+        logger.debug("Querying SETA service for low-value tasks on {}".format(project))
+        low_value_tasks = []
+
+        url = SETA_ENDPOINT % project
+        # Try to fetch the SETA data twice, falling back to an empty list of low value tasks.
+        # There are 10 seconds between each try.
+        try:
+            logger.debug("Retrieving low-value jobs list from SETA")
+            response = retry(requests.get, attempts=2, sleeptime=10,
+                             args=(url, ),
+                             kwargs={'timeout': 5, 'headers': headers})
+            task_list = json.loads(response.content).get('jobtypes', '')
+            if len(task_list) > 0:
+                low_value_tasks = task_list.values()[0]
+
+            # Bug 1315145, disable SETA for tier-1 platforms until backfill is implemented.
+            low_value_tasks = [x for x in low_value_tasks if x.find('debug') == -1]
+            low_value_tasks = [x for x in low_value_tasks if x.find('asan') == -1]
+
+        # In the event of request times out, requests will raise a TimeoutError.
+        except exceptions.Timeout:
+            logger.warning("SETA server is timeout, we will treat all test tasks as high value.")
+
+        # In the event of a network problem (e.g. DNS failure, refused connection, etc),
+        # requests will raise a ConnectionError.
+        except exceptions.ConnectionError:
+            logger.warning("SETA server is timeout, we will treat all test tasks as high value.")
+
+        # In the event of the rare invalid HTTP response(e.g 404, 401),
+        # requests will raise an HTTPError exception
+        except exceptions.HTTPError:
+            logger.warning("We got bad Http response from ouija,"
+                           " we will treat all test tasks as high value.")
+
+        # We just print the error out as a debug message if we failed to catch the exception above
+        except exceptions.RequestException as error:
+            logger.warning(error)
+
+        # When we get invalid JSON (i.e. 500 error), it results in a ValueError (bug 1313426)
+        except ValueError as error:
+            logger.warning("Invalid JSON, possible server error: {}".format(error))
+
+        return low_value_tasks
+
+    def is_low_value_task(self, label, project):
+        # cache the low value tasks per project to avoid repeated SETA server queries
+        if project not in self.low_value_tasks:
+            self.low_value_tasks[project] = self.query_low_value_tasks(project)
+        return label in self.low_value_tasks[project]
+
+# create a single instance of this class, and expose its `is_low_value_task`
+# bound method as a module-level function
+is_low_value_task = SETA().is_low_value_task