API consumers should be able to get insight into the query run times.
The UI currently measures total roundtrip times. This PR allows for more
fine grained metrics to be exposed.
* adds new timer for total execution time (queue + eval)
* expose new timer, queue timer, and eval timer in stats field of the
range query response:
```json
{
"status": "success",
"data": {
"resultType": "matrix",
"result": [],
"stats": {
"execQueueTimeNs": 4683,
"execTotalTimeNs": 2086587,
"totalEvalTimeNs": 2077851
}
}
}
```
* stats field is optional, only set when query parameter `stats` is not
empty
Try it via
```sh
curl 'http://localhost:9090/api/v1/query_range?query=up&start=1486480279&end=1486483879&step=14000&stats=true'
```
Review feedback
* moved query stats json generation to query_stats.go
* use seconds for all query timers
* expose all timers available
* Changed ExecTotalTime string representation from Exec queue total time to Exec total time
This PR fixes#3072 by providing POST endpoints for `query` and `query_range`.
POST request must be made with `Content-Type: application/x-www-form-urlencoded` header.
* Add UI warning for time drift >30 seconds
* Yellow time drift warning & better warning message
* Set warning threshold to 30 sec
* Include changed assets
* 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
No matter how we refactor docs, `/docs/` will stay the prefix, so there's not long-term risk in changing this.
One we version docs, we should probably try and keep link & version in sync.
Whenever a route prefix is applied, the router prepends the prefix to
the URL path on the request. For most handlers, this is not an issue
because the request's path is only used for routing and is not actually
needed by the handler itself. However, Prometheus delegates the handling
of the /debug/* endpoints to the http.DefaultServeMux which has it's own
routing logic that depends on the url.Path. As a result, whenever a
prefix is applied, the prefixed URL is passed to the DefaultServeMux
which has no awareness of the prefix and returns a 404.
This change fixes the issue by creating a new serveDebug handler which
routes requests /debug/* requests to appropriate net/http/pprof handler
and removing the net/http/pprof import in cmd/prometheus since it is no
longer necessary.
Fixes#2183.
