* reload: copy state on both name and labels
Fix https://github.com/prometheus/prometheus/issues/5193
Using just name causes the linked issue - if new rules are inserted with
the same name (but different labels), the reordering will cause stale
markers to be inserted in the next eval for all shifted rules, despite
them not being stale.
Ideally we want to avoid stale markers for time series that still exist
in the new rules, with name and labels being the unique identifer.
This change adds labels to the internal map when copying the old rule
data to the new rule data. This prevents the problem of staling rules
that simply shifted order.
If labels change, it is a new time series and the old series will stale
regardless. So it should be safe to always match on name and labels when
copying state.
Signed-off-by: James Ravn <james@r-vn.org>
Previously it would set no preconditions and check no postconditions,
as the `groups` member was empty.
Signed-off-by: Bryan Boreham <bjboreham@gmail.com>
This adds a parameter to the storage selection interface which allows
query engine(s) to pass information about the operations surrounding a
data selection.
This can for example be used by remote storage backends to infer the
correct downsampling aggregates that need to be provided.
* Use testutil in rules subpackage
* Fix manager test
* Use testutil in rules subpackage
* Fix manager test
* Fix rebase
* Change to testutil for applyConfig tests
* Re-add contexts to storage.Storage.Querier()
These are needed when replacing the storage by a multi-tenant
implementation where the tenant is stored in the context.
The 1.x query interfaces already had contexts, but they got lost in 2.x.
* Convert promql.Engine to use native contexts
Usually rules don't more around, and if they do it's likely
that rules/alerts with the same name stay in the same order.
If rules/alerts with the same name are added/removed this
could cause a blip for one cycle, but this is unavoidable
without requiring rule and alert names to be unique - which we don't
want to do.
This is based on https://github.com/prometheus/prometheus/pull/1997.
This adds contexts to the relevant Storage methods and already passes
PromQL's new per-query context into the storage's query methods.
The immediate motivation supporting multi-tenancy in Frankenstein, but
this could also be used by Prometheus's normal local storage to support
cancellations and timeouts at some point.
For Weaveworks' Frankenstein, we need to support multitenancy. In
Frankenstein, we initially solved this without modifying the promql
package at all: we constructed a new promql.Engine for every
query and injected a storage implementation into that engine which would
be primed to only collect data for a given user.
This is problematic to upstream, however. Prometheus assumes that there
is only one engine: the query concurrency gate is part of the engine,
and the engine contains one central cancellable context to shut down all
queries. Also, creating a new engine for every query seems like overkill.
Thus, we want to be able to pass per-query contexts into a single engine.
This change gets rid of the promql.Engine's built-in base context and
allows passing in a per-query context instead. Central cancellation of
all queries is still possible by deriving all passed-in contexts from
one central one, but this is now the responsibility of the caller. The
central query context is now created in main() and passed into the
relevant components (web handler / API, rule manager).
In a next step, the per-query context would have to be passed to the
storage implementation, so that the storage can implement multi-tenancy
or other features based on the contextual information.
