def on_put(self, req, resp, name):
"""
Handles the creation of a new Cluster.
:param req: Request instance that will be passed through.
:type req: falcon.Request
:param resp: Response instance that will be passed through.
:type resp: falcon.Response
:param name: The name of the Cluster being created.
:type name: str
"""
# PUT is idempotent, and since there's no body to this request,
# there's nothing to conflict with. The request should always
# succeed, even if we didn't actually do anything.
try:
Cluster.retrieve(name)
self.logger.info(
'Creation of already exisiting cluster {0} requested.'.format(
name))
except:
pass
cluster = Cluster(status='ok', hostset=[])
cluster.save(name)
self.logger.info(
'Created cluster {0} per request.'.format(name))
resp.status = falcon.HTTP_201
def etcd_cluster_add_host(name, address):
"""
Adds a host address to a cluster with the given name.
If no such cluster exists, the function raises KeyError.
Note the function is idempotent: if the host address is
already in the cluster, no change occurs.
:param name: Name of a cluster
:type name: str
:param address: Host address to add
:type address: str
"""
try:
cluster = Cluster.retrieve(name)
except:
raise KeyError
# FIXME: Need input validation.
# - Does the host exist at /commissaire/hosts/{IP}?
# - Does the host already belong to another cluster?
# FIXME: Should guard against races here, since we're fetching
# the cluster record and writing it back with some parts
# unmodified. Use either locking or a conditional write
# with the etcd 'modifiedIndex'. Deferring for now.
if address not in cluster.hostset:
cluster.hostset.append(address)
cluster.save(name)
def on_get(self, req, resp, name, address):
"""
Handles GET requests for individual hosts in a Cluster.
This is a membership test, returning 200 OK if the host
address is part of the cluster, or else 404 Not Found.
:param req: Request instance that will be passed through.
:type req: falcon.Request
:param resp: Response instance that will be passed through.
:type resp: falcon.Response
:param name: The name of the Cluster being requested.
:type name: str
:param address: The address of the Host being requested.
:type address: str
"""
try:
cluster = Cluster.retrieve(name)
except:
resp.status = falcon.HTTP_404
return
if address in cluster.hostset:
resp.status = falcon.HTTP_200
else:
resp.status = falcon.HTTP_404
def on_get(self, req, resp, name):
"""
Handles retrieval of an existing Cluster.
:param req: Request instance that will be passed through.
:type req: falcon.Request
:param resp: Response instance that will be passed through.
:type resp: falcon.Response
:param name: The name of the Cluster being requested.
:type name: str
"""
try:
cluster = Cluster.retrieve(name)
# key = util.etcd_cluster_key(name)
# etcd_resp, error = cherrypy.engine.publish('store-get', key)[0]
except:
resp.status = falcon.HTTP_404
return
if not cluster:
resp.status = falcon.HTTP_404
return
self._calculate_hosts(cluster)
# Have to set resp.body explicitly to include Hosts.
resp.body = cluster.to_json_with_hosts()
resp.status = falcon.HTTP_200
def on_put(self, req, resp, name):
"""
Handles PUT requests for Cluster hosts.
This replaces the entire host list for a Cluster.
:param req: Request instance that will be passed through.
:type req: falcon.Request
:param resp: Response instance that will be passed through.
:type resp: falcon.Response
:param name: The name of the Cluster being requested.
:type name: str
"""
try:
req_body = json.loads(req.stream.read().decode())
old_hosts = set(req_body['old']) # Ensures no duplicates
new_hosts = set(req_body['new']) # Ensures no duplicates
except (KeyError, TypeError):
self.logger.info(
'Bad client PUT request for cluster {0}: {1}'.
format(name, req_body))
resp.status = falcon.HTTP_400
return
try:
cluster = Cluster.retrieve(name)
except:
resp.status = falcon.HTTP_404
return
# old_hosts must match current hosts to accept new_hosts.
# Note: Order doesn't matter, so etcd's atomic comparison
# of the raw values would be too strict.
if old_hosts != set(cluster.hostset):
self.logger.info(
'Conflict setting hosts for cluster {0}'.format(name))
resp.status = falcon.HTTP_409
return
# FIXME: Need input validation. For each new host,
# - Does the host exist at /commissaire/hosts/{IP}?
# - Does the host already belong to another cluster?
# FIXME: Should guard against races here, since we're fetching
# the cluster record and writing it back with some parts
# unmodified. Use either locking or a conditional write
# with the etcd 'modifiedIndex'. Deferring for now.
cluster.hostset = list(new_hosts)
cluster.save(name)
resp.status = falcon.HTTP_200
def etcd_cluster_has_host(name, address):
"""
Checks if a host address belongs to a cluster with the given name.
If no such cluster exists, the function raises KeyError.
:param name: Name of a cluster
:type name: str
:param address: Host address
:type address: str
"""
try:
cluster = Cluster.retrieve(name)
except:
raise KeyError
return address in cluster.hostset
def on_get(self, req, resp, name):
"""
Handles GET requests for Cluster hosts.
:param req: Request instance that will be passed through.
:type req: falcon.Request
:param resp: Response instance that will be passed through.
:type resp: falcon.Response
:param name: The name of the Cluster being requested.
:type name: str
"""
try:
cluster = Cluster.retrieve(name)
except:
resp.status = falcon.HTTP_404
return
resp.body = json.dumps(cluster.hostset)
resp.status = falcon.HTTP_200
def on_delete(self, req, resp, address):
"""
Handles the Deletion of a Host.
:param req: Request instance that will be passed through.
:type req: falcon.Request
:param resp: Response instance that will be passed through.
:type resp: falcon.Response
:param address: The address of the Host being requested.
:type address: str
"""
resp.body = "{}"
try:
Host.delete(address)
resp.status = falcon.HTTP_200
except:
resp.status = falcon.HTTP_404
# Also remove the host from all clusters.
# Note: We've done all we need to for the host deletion,
# so if an error occurs from here just log it and
# return.
try:
clusters = Clusters.retrieve()
except:
self.logger.warn("Etcd does not have any clusters")
return
try:
for cluster_name in clusters.clusters:
self.logger.debug("Checking cluster {0}".format(cluster_name))
cluster = Cluster.retrieve(cluster_name)
if address in cluster.hostset:
self.logger.info("Removing {0} from cluster {1}".format(address, cluster_name))
cluster.hostset.remove(address)
cluster.save(cluster_name)
self.logger.info("{0} has been removed from cluster {1}".format(address, cluster_name))
except:
self.logger.warn("Failed to remove {0} from cluster {1}".format(address, cluster_name))
