0529f0ca3a
If value meta length is larger than the size of the Vertica column, the write will fail and cause the persister to die. Check the length and drop the value meta if too large. This should not occur as the value meta is validated by the API before being written to Kafka, but this is a cheap check and ensures the persister will stay up if some application starts writing directly to the Kafka queue Change-Id: I893d02751217beb6ba5a88625f20448c45a1b376
monasca-persister
The Monitoring Persister consumes metrics and alarm state transitions from the Message Queue and stores them in the Metrics and Alarms database.
Although the Persister isn't primarily a Web service it uses DropWizard, https://dropwizard.github.io/dropwizard/, which provides a nice Web application framework to expose an http endpoint that provides an interface through which metrics about the Persister can be queried as well as health status.
The basic design of the Persister is to have one Kafka consumer publish to a Disruptor, https://github.com/LMAX-Exchange/disruptor, that has output processors. The output processors use prepared batch statements to write to the Metrics and Alarms database.
The number of output processors/threads in the Persister can be specified to scale to more messages. To horizontally scale and provide fault-tolerance any number of Persisters can be started as consumers from the the Message Queue.
Build
Requires monasca-common from https://github.com/openstack/monasca-common. Download and build following instructions in its README.md. Then build monasca-persister by:
mvn clean package
Configuration
A sample configuration file is available in java/src/deb/etc/persister-config.yml-sample.
A second configuration file is provided in java/src/main/resources/persister-config.yml for use with the vagrant "mini-mon" development environment.
TODO
- Purge metrics on shutdown
- Add more robust offset management in Kafka. Currently, the offset is advanced as each message is read. If the Persister stops after the metric has been read and prior to it being committed to the Metrics and Alarms database, the metric will be lost.
- Add better handling of SQL exceptions.
- Complete health check.
- Specify and document the names of the metrics that are available for monitoring of the Persister.
- Document the yaml configuration parameters.
License
Copyright (c) 2014 Hewlett-Packard Development Company, L.P.
Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in compliance with the License. You may obtain a copy of the License at
http://www.apache.org/licenses/LICENSE-2.0
Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License for the specific language governing permissions and limitations under the License.