* vmalert: add flag to limit the max value for auto-resovle duration for alerts
The new flag `rule.maxResolveDuration` suppose to limit max value for
alert.End param, which is used by notifiers like Alertmanager for alerts auto resolve.
https://github.com/VictoriaMetrics/VictoriaMetrics/issues/1586
The commit adds a support for template function `query`,
`first` and `value`. The function `query` executes
a MetricsQL query for active alerts. In vmalert we
update templates on every evaluation for active alerts
to keep them up to date. With `query` func it may become
a perf issue since it will fire a query on every execution.
We should keep it in mind for now.
https://github.com/VictoriaMetrics/VictoriaMetrics/issues/539
* app/vmalert: support multiple notifier urls (#584)
User now can set multiple notifier URLs in the same fashion
as for other vmutils (e.g. vmagent). The same is correct for
TLS setting for every configured URL. Alerts sending is done
in sequential way for respecting the specified URLs order.
* app/vmalert: add basicAuth support for notifier client (#585)
The change adds possibility to set basicAuth creds for notifier
client in the same fasion as for remote write/read and datasource.
* vmalert: Add recording rules support.
Recording rules support required additional service refactoring since
it wasn't planned to support them from the very beginning. The list
of changes is following:
* new entity RecordingRule was added for writing results of MetricsQL
expressions into remote storage;
* interface Rule now unites both recording and alerting rules;
* configuration parser was moved to separate package and now performs
more strict validation;
* new endpoint for listing all groups and rules in json format was added;
* evaluation interval may be set to every particular group;
* vmalert: uncomment tests
* vmalert: rm outdated TODO
* vmalert: fix typos in README
The change introduces new entity `manager` which replaces
`watchdog`, decouples requestHandler and groups. Manager
supposed to control life cycle of groups, rules and
config reloads.
Groups export an ID method which returns a hash
from filename and group name. ID supposed to be unique
identifier across all loaded groups.
Some tests were added to improve coverage.
Bug with wrong annotation value if $value is used in
templates after metrics being restored fixed.
Notifier interface was extended to accept context.
New set of metrics was introduced for config reload.
