Giuseppe Lavagetto has uploaded a new change for review.
https://gerrit.wikimedia.org/r/238152
Change subject: Add instrumentation
......................................................................
Add instrumentation
Pybal has always been pretty private on its own internal state to
outside observers, making it a bit difficult to monitor or poll its
state.
We add a simple HTTP listener chain of monitoring endpoints describing
the actual state (pooled/depooled, up/down) of all servers (or a single
one) in a pool
Url space is left free for others to use for stats or other kind of
instrumentation in the future.
UNTESTED MOCK.
Bug: T102394
Change-Id: Ied88d44e63f91df3816df4b44f29bb0cd444cd05
---
M pybal/__init__.py
A pybal/instrumentation.py
M pybal/pybal.py
3 files changed, 115 insertions(+), 3 deletions(-)
git pull ssh://gerrit.wikimedia.org:29418/operations/debs/pybal
refs/changes/52/238152/1
diff --git a/pybal/__init__.py b/pybal/__init__.py
index 20d9e50..e838db5 100644
--- a/pybal/__init__.py
+++ b/pybal/__init__.py
@@ -11,4 +11,4 @@
USER_AGENT_STRING = 'PyBal/%s' % __version__
__all__ = ('ipvs', 'monitor', 'pybal', 'util', 'monitors', 'bgp',
- 'config', 'USER_AGENT_STRING')
+ 'config', 'instrumentation', 'USER_AGENT_STRING')
diff --git a/pybal/instrumentation.py b/pybal/instrumentation.py
new file mode 100644
index 0000000..c76ef80
--- /dev/null
+++ b/pybal/instrumentation.py
@@ -0,0 +1,98 @@
+"""
+ Instrumentation HTTP server for PyBal
+ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+ A simple http server that can return the state of a pool,
+ or the state of a single server within a pool.
+
+ Urls:
+
+ /pools - a list of the available pools
+ /pools/<pool> - The full state of a pool
+ /pools/<pool>/<host> - the state of a single host in a pool
+
+ All results are returned either as human-readable lists or as json
+ structures, depending on the Accept header of the request.
+"""
+
+from twisted.web.resource import Resource
+import json
+
+
+def renderConditional(msg, request):
+ if request.requestHeaders.hasHeader('Accept'):
+ val = request.requestHeaders.getRawHeaders('Accept')
+ if 'application/json' in val:
+ return json.dumps(msg)
+ else:
+ return str(msg)
+
+
+class Resp404(Resource):
+ isLeaf = True
+
+ def render_GET(self, request):
+ request.setResponseCode(404)
+ msg = {'error':
+ "The desired url {} was not found".format(request.path)}
+ return renderConditional(msg, request)
+
+
+def Server(Resource):
+
+ def getChild(self, path, request):
+ if path == 'pools':
+ return PoolsRoot()
+ else:
+ return Resp404()
+
+
+class PoolsRoot(Resource):
+ _pools = {}
+
+ def __init__(self):
+ Resource.__init__(self)
+
+ @classmethod
+ def addPool(cls, coordinator):
+ cls._pools[coordinator.lvsservice.name] = coordinator
+
+ def getChild(self, path, request):
+ if not path:
+ return self
+ if path in self._pools:
+ return PoolServers(self._pools[path])
+ return Resp404()
+
+ def render_GET(self, request):
+ return renderConditional(self._pools.keys())
+
+
+class PoolServers(Resource):
+
+ def __init__(self, coordinator):
+ Resource.__init__(self)
+ self.coordinator = coordinator
+
+ def getChild(self, path, request):
+ if not path:
+ return self
+ if path in self.coordinator.servers:
+ return PoolServer(self.coordinator.servers[path])
+ return Resp404()
+
+ def render_GET(self, request):
+ res = {}
+ for hostname, server in self.coordinator.servers.items():
+ res[hostname] = server.dumpState()
+ return renderConditional(res, request)
+
+
+class PoolServer(Resource):
+ isLeaf = True
+
+ def __init__(self, server):
+ self.state = server.dumpState()
+
+ def render_GET(self, request):
+ return renderConditional(self.state, request)
diff --git a/pybal/pybal.py b/pybal/pybal.py
index ea6cf63..e0eb286 100755
--- a/pybal/pybal.py
+++ b/pybal/pybal.py
@@ -10,7 +10,7 @@
from __future__ import absolute_import
import os, sys, signal, socket, random
-from pybal import ipvs, monitor, util, config
+from pybal import ipvs, monitor, util, config, instrumentation
from twisted.python import failure, filepath
from twisted.internet import reactor, defer
@@ -25,6 +25,7 @@
from pybal import bgp
except ImportError:
pass
+
class Server:
"""
@@ -245,6 +246,10 @@
self.maintainState()
self.modified = True # Indicate that this instance previously
existed
+ def dumpState(self):
+ """Dump current state of the server"""
+ return {'pooled': self.pooled, 'weight': self.weight, 'up': self.up}
+
@classmethod
def buildServer(cls, hostName, configuration, lvsservice):
"""
@@ -257,6 +262,7 @@
server.modified = False
return server
+
class Coordinator:
"""
@@ -413,6 +419,7 @@
# Assign the updated list of enabled servers to the LVSService instance
self.assignServers()
+
class BGPFailover:
"""Class for maintaining a BGP session to a router for IP address
failover"""
@@ -681,7 +688,7 @@
crd = Coordinator(services[section],
configUrl=config.get(section, 'config'))
print "Created LVS service '%s'" % section
-
+ instrumentation.PoolsRoot.addPool(crd)
# Set up BGP
try:
@@ -691,6 +698,13 @@
configdict.update(cliconfig)
bgpannouncement = BGPFailover(configdict)
+ # Run the web server for instrumentation
+ if configdict.get('instrumentation', False):
+ from twisted.web.server import Site
+ port = configdict.get('instrumentation_port', 9090)
+ factory = Site(instrumentation.Server())
+ reactor.listenTCP(port, factory)
+
reactor.run()
finally:
terminate()
--
To view, visit https://gerrit.wikimedia.org/r/238152
To unsubscribe, visit https://gerrit.wikimedia.org/r/settings
Gerrit-MessageType: newchange
Gerrit-Change-Id: Ied88d44e63f91df3816df4b44f29bb0cd444cd05
Gerrit-PatchSet: 1
Gerrit-Project: operations/debs/pybal
Gerrit-Branch: master
Gerrit-Owner: Giuseppe Lavagetto <glavage...@wikimedia.org>
_______________________________________________
MediaWiki-commits mailing list
MediaWiki-commits@lists.wikimedia.org
https://lists.wikimedia.org/mailman/listinfo/mediawiki-commits
