commit	4fe84fbc2b4088eb84077538afc46855bfb9fbec	[log] [tgz]
author	Antonio Barone <syntonyze@gmail.com>	Wed Oct 21 13:32:00 2020 +0200
committer	Luca Milanesio <luca.milanesio@gmail.com>	Fri Oct 23 20:04:13 2020 +0000
tree	b49b925052495bba622be7622643a953eadb7fe6
parent	fc0e3062d07dc60c1faef9d33108b9781e890297 [diff]

tree: b49b925052495bba622be7622643a953eadb7fe6

README.md

Plugin to verify the Gerrit health status

Allow having a single entry point to check the availability of the services that Gerrit exposes.

How to build

Clone or link this plugin to the plugins directory of Gerrit‘s source tree, and then run bazel build on the plugin’s directory.

Example:

git clone --recursive https://gerrit.googlesource.com/gerrit
git clone https://gerrit.googlesource.com/plugins/healthcheck
pushd gerrit/plugins && ln -s ../../healthcheck . && popd
cd gerrit && bazel build plugins/healthcheck

The output plugin jar is created in:

bazel-genfiles/plugins/healthcheck/healthcheck.jar

How to install

Copy the healthcheck.jar into the Gerrit's /plugins directory and wait for the plugin to be automatically loaded. The healthcheck plugin is compatible with both Gerrit master and slave setups. The only difference to bear in mind is that some checks will be automatically disabled on slaves (e.g. query changes) because the associated subsystem is switched off.

How to use

The healthcheck plugin exposes a single endpoint under its root URL and provides a JSON output of the Gerrit health status.

The HTTP status code returned indicates whether Gerrit is healthy (HTTP status 200) or has some issues (HTTP status 500).

The HTTP response payload is a JSON output that contains the details of the checks performed.

ts: epoch timestamp in millis of the test
elapsed: elapsed time in millis to perform the check
querychanges: check that Gerrit can query changes
reviewdb: check that Gerrit can connect and query ReviewDb
projectslist: check that Gerrit can list projects
jgit: check that Gerrit can access repositories

Each check returns a JSON payload with the following information:

ts: epoch timestamp in millis of the individual check
elapsed: elapsed time in millis to complete the check
result: result of the health check
- passed: the check passed successfully
- disabled: the check was disabled
- failed: the check failed with an error
- timeout: the check took too long and timed out

Example of a healthy Gerrit response:

GET /config/server/healthcheck~status

200 OK
Content-Type: application/json

)]}'
{
  "ts": 139402910202,
  "elapsed": 100,
  "querychanges": {
    "ts": 139402910202,
    "elapsed": 20,
    "result": "passed"
  },
  "reviewdb": {
    "ts": 139402910202,
    "elapsed": 50,
    "result": "passed"
  },
  "projectslist": {
    "ts": 139402910202,
    "elapsed": 100,
    "result": "passed"
  },
  "jgit": {
    "ts": 139402910202,
    "elapsed": 80,
    "result": "passed"
  }
}

Example of a Gerrit instance with the projects list timing out:

GET /config/server/healthcheck~status

500 ERROR
Content-Type: application/json

)]}'
{
  "ts": 139402910202,
  "elapsed": 100,
  "querychanges": {
    "ts": 139402910202,
    "elapsed": 20,
    "result": "passed"
  },
  "reviewdb": {
    "ts": 139402910202,
    "elapsed": 50,
    "result": "passed"
  },
  "projectslist": {
    "ts": 139402910202,
    "elapsed": 100,
    "result": "timeout"
  },
  "jgit": {
    "ts": 139402910202,
    "elapsed": 80,
    "result": "passed"
  }
}

Metrics

As for all other endpoints in Gerrit, some metrics are automatically emitted when the /config/server/healthcheck~status endpoint is hit (thanks to the Dropwizard library).

Some additional metrics are also produced to give extra insights on their result about results and latency of healthcheck sub component, such as jgit, reviewdb, etc.

More information can be found in the config.md file.