backfiller database code

backfiller/backfiller/main.py

@@ -16,8 +16,8 @@ import prometheus_client as prom
 import requests
 
 import common
-import common.dateutil
-
+from common import dateutil
+from common import database
 
 segments_backfilled = prom.Counter(
 	'segments_backfilled',
@@ -188,6 +188,9 @@ class BackfillerManager(object):
 		get_nodes are stopped. If self.run_once, only call nodes once. Calling
 		stop will exit the loop."""
 		self.logger.info('Starting')
+		if self.node_database is not None:
+			self.db_manager = database.DBManager(dsn=self.node_database)
+
 		failures = 0
 
 		while not self.stopping.is_set():
@@ -222,18 +225,17 @@ class BackfillerManager(object):
 		
 		This returns a list of the other wubloaders as URL strings. Node URLs
 		are taken from three places. First, the --static-nodes command line
-		argument can be used to provide a list of addresses that are always
+		argument can be used to provide a list of URLs that are always
 		backfilled from. Node names infered from the hostnames of the URLs.
-		Second, addresses are read from the file named in the --node-file
-		command line argument. In this file, nodes are listed one per line as
-		node name node address pairs or as just node addresses. Lines starting
-		with '#' are ignored. If only the address is provided, the node name is
-		taken from the hostname. Third, node names and addresses can be
-		requested from the database with the database address. If multiple
-		nodes address with the same name are found, only the last is retained
-		and any nodes matching the local host name (given by the --hostname)
-		argument are ignored to try to prevent this node from backfilling from
-		its self."""
+		Second, nodes are read from the file named in the --node-file command
+		line argument. In this file, nodes are listed one per line as name-URL
+		pairs or as just node URLs. Lines starting with '#' are ignored. If
+		only the URL is provided, the node name is taken from the hostname.
+		Third, node names and URLs can be requested from the database given by
+		--node-database. If multiple nodes URLs with the same name are found,
+		only the last is retained and any nodes matching the local hostname
+		(given by the --hostname argument) are ignored to try to prevent this
+		node from backfilling from its self."""
 
 		nodes = {urlparse.urlparse(node).hostname:node for node in self.static_nodes}
 		
@@ -250,8 +252,15 @@ class BackfillerManager(object):
 						nodes[substrs[0]] = substrs[1]
 
 		if self.node_database is not None:
-			self.logger.info('Fetching list of nodes from {}'.format(self.node_database))
-			# TODO query the database
+			self.logger.info('Fetching list of nodes from {}'.format(
+				urlparse.urlparse(self.node_database).hostname))
+			conn = self.db_manager.query()
+			results = database.query(conn, """
+				SELECT name, url, backfill_from
+				FROM nodes""")
+			for row in results:
+				if row.backfill_from:
+					nodes[row.name] = row.url
 
 		nodes.pop(self.localhost, None)
 		return nodes.values()
@@ -368,7 +377,7 @@ class BackfillerWorker(object):
 @argh.arg('--start', help='If a datetime only backfill hours after that datetime. If a number, bacfill hours more recent than that number of hours ago. If None (default), all hours are backfilled.')
 @argh.arg('--run-once', help='If True, backfill only once. By default False.')
 @argh.arg('--node-file', help="Name of file listing nodes to backfill from. One node per line in the form NAME URI with whitespace only lines or lines starting with '#' ignored. If None (default) do not get nodes from a file.")
-@argh.arg('--node-database', help='Address of database node to fetch a list of nodes from. If None (default) do not get nodes from database.')
+@argh.arg('--node-database', help='Postgres conection string for database to fetch a list of nodes from. Either a space-separated list of key=value pairs, or a URI like: postgresql://USER:PASSWORD@HOST/DBNAME?KEY=VALUE . If None (default) do not get nodes from database.')
 @argh.arg('--localhost', help='Name of local machine. Used to prevent backfilling from itself. By default the result of socket.gethostname()')
 def main(streams, base_dir='.', variants='source', metrics_port=8002,
 	static_nodes='', backdoor_port=0, start=None, run_once=False,
@@ -385,7 +394,7 @@ def main(streams, base_dir='.', variants='source', metrics_port=8002,
 			start = float(start)
 			logging.info('Backfilling last {} hours'.format(start))
 		except ValueError:
-			start = common.dateutil.parse(start)
+			start = dateutil.parse(start)
 			logging.info('Backfilling since {}'.format(start)) 
 
 	common.PromLogCountsHandler.install()

common/common/database.py

@@ -59,6 +59,12 @@ CREATE TABLE IF NOT EXISTS events (
 -- Index on state, since that's almost always what we're querying on besides id
 CREATE INDEX IF NOT EXISTS event_state ON events (state);
 
+CREATE TABLE IF NOT EXISTS nodes (
+	name TEXT PRIMARY KEY,
+	url TEXT NOT NULL,
+	backfill_from BOOLEAN NOT NULL DEFAULT TRUE
+);
+
 """