Commit graph

244 commits

Author SHA1 Message Date
Julien Pivotto db2d759b81 Add support for lookbackdelta per query via the API
Signed-off-by: Julien Pivotto <roidelapluie@o11y.eu>
2023-03-08 00:30:05 +01:00
Marco Pracucci 3db77b4491
API: change HTTP status code tracked in metrics form 503/422 to 499 if a request is canceled
Signed-off-by: Marco Pracucci <marco@pracucci.com>
2023-01-26 13:06:37 +01:00
Julien Pivotto 2c408289f8 Add stabilizing to UI
Signed-off-by: Julien Pivotto <roidelapluie@o11y.eu>
2023-01-19 11:33:54 +01:00
Julien Pivotto ce55e5074d Add 'keep_firing_for' field to alerting rules
This commit adds a new 'keep_firing_for' field to Prometheus alerting
rules. The 'resolve_delay' field specifies the minimum amount of time
that an alert should remain firing, even if the expression does not
return any results.

This feature was discussed at a previous dev summit, and it was
determined that a feature like this would be useful in order to allow
the expression time to stabilize and prevent confusing resolved messages
from being propagated through Alertmanager.

This approach is simpler than having two PromQL queries, as was
sometimes discussed, and it should be easy to implement.

This commit does not include tests for the 'resolve_delay' field.  This
is intentional, as the purpose of this commit is to gather comments on
the proposed design of the 'resolve_delay' field before implementing
tests. Once the design of the 'resolve_delay' field has been finalized,
a follow-up commit will be submitted with tests."

See https://github.com/prometheus/prometheus/issues/11570

Signed-off-by: Julien Pivotto <roidelapluie@o11y.eu>
2023-01-13 12:11:39 +01:00
Łukasz Mierzwa e1b7082008
Show individual scrape pools on /targets page (#11142)
* Add API endpoints for getting scrape pool names

This adds api/v1/scrape_pools endpoint that returns the list of *names* of all the scrape pools configured.
Having it allows to find out what scrape pools are defined without having to list and parse all targets.

The second change is adding scrapePool query parameter support in api/v1/targets endpoint, that allows to
filter returned targets by only finding ones for passed scrape pool name.

Both changes allow to query for a specific scrape pool data, rather than getting all the targets for all possible scrape pools.
The problem with api/v1/targets endpoint is that it returns huge amount of data if you configure a lot of scrape pools.

Signed-off-by: Łukasz Mierzwa <l.mierzwa@gmail.com>

* Add a scrape pool selector on /targets page

Current targets page lists all possible targets. This works great if you only have a few scrape pools configured,
but for systems with a lot of scrape pools and targets this slow things down a lot.
Not only does the /targets page load very slowly in such case (waiting for huge API response) but it also take
a long time to render, due to huge number of elements.
This change adds a dropdown selector so it's possible to select only intersting scrape pool to view.
There's also scrapePool query param that will open selected pool automatically.

Signed-off-by: Łukasz Mierzwa <l.mierzwa@gmail.com>

Signed-off-by: Łukasz Mierzwa <l.mierzwa@gmail.com>
2022-12-23 11:55:08 +01:00
Ganesh Vernekar e3719d670b
Merge remote-tracking branch 'upstream/main' into sparsehistogram
Signed-off-by: Ganesh Vernekar <ganeshvern@gmail.com>
2022-10-25 14:38:56 -04:00
Alan Protasio 5ac12ac351
api: Wrapped promQL based API errors with returnAPIError function (#11356)
* wrap api error on get series/labels on `returnAPIError` function

Signed-off-by: Alan Protasio <approtas@amazon.com>

* lint

Signed-off-by: Alan Protasio <approtas@amazon.com>

* query exemplars

Signed-off-by: Alan Protasio <approtas@amazon.com>

Signed-off-by: Alan Protasio <approtas@amazon.com>
2022-10-20 11:17:00 +02:00
Jesus Vazquez e934d0f011 Merge 'main' into sparsehistogram
Signed-off-by: Jesus Vazquez <jesus.vazquez@grafana.com>
2022-10-05 22:14:49 +02:00
Bryan Boreham 3330d85ba8
Replace sort.Strings and sort.Ints with faster slices.Sort (#11318)
Use new experimental package `golang.org/x/exp/slices`.

slices.Sort works on values that are directly comparable, like ints,
so avoids the overhad of an interface call to `.Less()`.

Left tests unchanged, because they don't need the speed and it may be
a cross-check that slices.Sort gives the same answer.

Signed-off-by: Bryan Boreham <bjboreham@gmail.com>
2022-09-30 20:03:56 +05:30
Miguel Ángel Ortuño e4b87a7a2a
api: export point marshaling functions (#11323)
Export `marshalTimestamp` and `marshalValue` functions by moving them under their own util package.

Signed-off-by: Miguel Ángel Ortuño <ortuman@gmail.com>
2022-09-29 20:16:48 +05:30
Alan Protasio f1a3dbbb6b
GetSeries should Select sorted results only if more than one matcher is requested (#11313)
Signed-off-by: Alan Protasio <approtas@amazon.com>

Signed-off-by: Alan Protasio <approtas@amazon.com>
2022-09-16 09:40:41 +02:00
Julien Pivotto 96d5a32659
Update go to 1.19, set min version to 1.18 (#11279)
* Update go to 1.19, set min version to 1.18

Signed-off-by: Julien Pivotto <roidelapluie@o11y.eu>

* Update golangci-lint

Signed-off-by: Julien Pivotto <roidelapluie@o11y.eu>

Signed-off-by: Julien Pivotto <roidelapluie@o11y.eu>
2022-09-07 11:30:48 +02:00
beorn7 c9fd3c235d Merge branch 'main' into sparsehistogram 2022-08-10 17:54:37 +02:00
Julius Volz b57deb6eb0
Add /api/v1/format_query API endpoint for formatting queries (#11036)
* Add /api/v1/format_query API endpoint for formatting queries

This uses the formatting functionality introduced in
https://github.com/prometheus/prometheus/pull/10544.

I've chosen "query" instead of "expr" in both the endpoint and parameter
names to stay consistent with the existing API endpoints. Otherwise, I
would have preferred to use the term "expr".

Signed-off-by: Julius Volz <julius.volz@gmail.com>

* Add docs for /api/v1/format_query endpoint

Signed-off-by: Julius Volz <julius.volz@gmail.com>

* Add note that formatting expressions removes comments

Signed-off-by: Julius Volz <julius.volz@gmail.com>
2022-07-20 14:55:09 +02:00
beorn7 095b6c93dd Merge branch 'main' into sparsehistogram 2022-06-14 14:27:35 +02:00
Peter Štibraný 5bd761fbfc
Merge pull request #10857 from pstibrany/fix-errors-handling
API: Fix errors handling
2022-06-13 17:45:35 +02:00
beorn7 40ad5e284a Merge branch 'main' into beorn7/sparsehistogram 2022-06-09 20:50:30 +02:00
Filip Petkovski a56731126d
Export TSDB status structs (#10783)
We would like to implement the tsdb/status API in certain Thanos
components.

In order to match the Prometheus API and avoid duplicating code,
this commit makes the structs used in the status API public.

Signed-off-by: Filip Petkovski <filip.petkovsky@gmail.com>
2022-06-07 16:13:21 +01:00
beorn7 d16b314b72 Histogram: Do not render empty buckets in JSON output
While empty buckets can make sense in the internal representation (by
joining spans that would otherwise need more overhead for separate
representation), there are no spans in the JSON rendering. Therefore,
the JSON should not contain any empty buckets, since any buckets not
included in the output counts as empty anyway.

This changes both the inefficient MarshalJSON implementation as well
as the jsoniter implementation.

Signed-off-by: beorn7 <beorn@grafana.com>
2022-05-03 18:18:55 +02:00
beorn7 61d6d1df18 Histogram: Remove obsolete work-around code
Signed-off-by: beorn7 <beorn@grafana.com>
2022-05-03 17:57:52 +02:00
beorn7 37bbc07118 Histogram: Add jsoniter marshaling
This now even enables jsoniter marshaling of Points in an instant
query (which previously used the traditional JSON marshaling).

Signed-off-by: beorn7 <beorn@grafana.com>
2022-04-26 15:19:59 +02:00
beorn7 99894f6afa Histogram: Implement inefficient JSON rendering
Format is according to example 4 in
https://docs.google.com/document/d/1Efu0LX-fgNWix6ehfeCR0FzeWtHvftWFNoy7cYW9nqU/edit#

This is inefficient as it doesn't use jsoniter. It actually prevents
it for regular Points (with a conventional float Value), too.

Signed-off-by: beorn7 <beorn@grafana.com>
2022-04-14 20:38:49 +02:00
beorn7 4210aac74a Merge branch 'main' into sparsehistogram 2022-03-22 14:47:42 +01:00
Andrew Bloomgarden ed091a1fb9 Allow replacing the stats struct before rendering JSON
This allows other implementations to inject their own statistics that
they're gathering in data linked from the context.Context. For example,
Cortex can inject its stats.Stats value under the `cortex` key.

Signed-off-by: Andrew Bloomgarden <blmgrdn@amazon.com>
2022-03-21 23:49:17 +01:00
Alan Protasio 606ef33d91 Track and report Samples Queried per query
We always track total samples queried and add those to the standard set
of stats queries can report.

We also allow optionally tracking per-step samples queried. This must be
enabled both at the engine and query level to be tracked and rendered.
The engine flag is exposed via a Prometheus feature flag, while the
query flag is set when stats=all.

Co-authored-by: Alan Protasio <approtas@amazon.com>
Co-authored-by: Andrew Bloomgarden <blmgrdn@amazon.com>
Co-authored-by: Harkishen Singh <harkishensingh@hotmail.com>
Signed-off-by: Andrew Bloomgarden <blmgrdn@amazon.com>
2022-03-21 23:49:17 +01:00
Łukasz Mierzwa a4317bf0ec
Run gofumpt on all files (#10392)
* Run gofumpt on all files

Getting golangci-lint errors when building on my laptop, possibly because I have newer version of gofumpt then what it was formatted with.
Run gofumpt -w -extra on all files as it will be needed in the future anyway.

* Update golangci-lint to v1.44.2

v1.44.0 upgraded gofumpt so bumping version in CI will help keep formatting correct for everyone

* Address golangci-lint error

Getting 'error-strings: error strings should not be capitalized or end with punctuation or a newline' from revive here.
Drop new line.

Signed-off-by: Łukasz Mierzwa <l.mierzwa@gmail.com>
2022-03-03 17:21:05 +01:00
Julien Pivotto 9a2e93228e
Switch to grafana/regexp everywhere (#10268)
Let's have a consistent library for regexp.

Signed-off-by: Julien Pivotto <roidelapluie@inuits.eu>
2022-02-13 00:58:27 +01:00
Björn Rabenstein 933f50bcda
Merge pull request #10121 from prometheus/beorn7/promql
PromQL: Promote negative offset and @ modifer to stable
2022-01-12 14:09:46 +01:00
Abhishek 2f4289a3bf
add limit to the rules api (#10152) 2022-01-11 22:44:22 -05:00
beorn7 b39f2739e5 PromQL: Always enable negative offset and @ modifier
This follows the line of argument that the invariant of not looking
ahead of the query time was merely emerging behavior and not a
documented stable feature. Any query that looks ahead of the query
time was simply invalid before the introduction of the negative offset
and the @ modifier.

Signed-off-by: beorn7 <beorn@grafana.com>
2022-01-11 17:08:55 +01:00
Oleg Zaytsev 3c400d443d
Accept promql.Engine interface in v1.NewAPI() (#10050)
Instead of requesting a concrete type. This would allow other
implementations that use the same API to replace or wrap the engine
implementation while maintaining the same API.

Signed-off-by: Oleg Zaytsev <mail@olegzaytsev.com>
2021-12-21 11:22:40 +01:00
beorn7 e4e24453fa Merge branch 'main' into beorn7/merge2 2021-11-30 17:19:06 +01:00
Ganesh Vernekar 0eac720468
Export rules related structs in web/api/v1 (#9831)
Signed-off-by: Ganesh Vernekar <ganeshvern@gmail.com>
2021-11-21 22:30:27 +05:30
beorn7 5d4db805ac Merge branch 'main' into sparsehistogram 2021-11-17 19:57:31 +01:00
beorn7 c954cd9d1d Move packages out of deprecated pkg directory
This creates a new `model` directory and moves all data-model related
packages over there:
  exemplar labels relabel rulefmt textparse timestamp value

All the others are more or less utilities and have been moved to `util`:
  gate logging modetimevfs pool runtime

Signed-off-by: beorn7 <beorn@grafana.com>
2021-11-09 08:03:10 +01:00
Mateusz Gozdek 1a6c2283a3 Format Go source files using 'gofumpt -w -s -extra'
Part of #9557

Signed-off-by: Mateusz Gozdek <mgozdekof@gmail.com>
2021-11-02 19:52:34 +01:00
Robert Fratto bc72a718c4
Initial draft of prometheus-agent (#8785)
* Initial draft of prometheus-agent

This commit introduces a new binary, prometheus-agent, based on the
Grafana Agent code. It runs a WAL-only version of prometheus without the
TSDB, alerting, or rule evaluations. It is intended to be used to
remote_write to Prometheus or another remote_write receiver.

By default, prometheus-agent will listen on port 9095 to not collide
with the prometheus default of 9090.

Truncation of the WAL cooperates on a best-effort case with Remote
Write. Every time the WAL is truncated, the minimum timestamp of data to
truncate is determined by the lowest sent timestamp of all samples
across all remote_write endpoints. This gives loose guarantees that data
from the WAL will not try to be removed until the maximum sample
lifetime passes or remote_write starts functionining.

Signed-off-by: Robert Fratto <robertfratto@gmail.com>

* add tests for Prometheus agent (#22)

* add tests for Prometheus agent

* add tests for Prometheus agent

* rearranged tests as per the review comments

* update tests for Agent

* changes as per code review comments

Signed-off-by: SriKrishna Paparaju <paparaju@gmail.com>

* incremental changes to prometheus agent

Signed-off-by: SriKrishna Paparaju <paparaju@gmail.com>

* changes as per code review comments

Signed-off-by: SriKrishna Paparaju <paparaju@gmail.com>

* Commit feedback from code review

Co-authored-by: Bartlomiej Plotka <bwplotka@gmail.com>
Co-authored-by: Ganesh Vernekar <ganeshvern@gmail.com>

Signed-off-by: Robert Fratto <robertfratto@gmail.com>

* Port over some comments from grafana/agent

Signed-off-by: Robert Fratto <robertfratto@gmail.com>

* Rename agent.Storage to agent.DB for tsdb consistency

Signed-off-by: Robert Fratto <robertfratto@gmail.com>

* Consolidate agentMode ifs in cmd/prometheus/main.go

Signed-off-by: Robert Fratto <robertfratto@gmail.com>

* Document PreAction usage requirements better for agent mode flags

Signed-off-by: Robert Fratto <robertfratto@gmail.com>

* remove unnecessary defaultListenAddr

Signed-off-by: Robert Fratto <robertfratto@gmail.com>

* `go fmt ./tsdb/agent` and fix lint errors

Signed-off-by: Robert Fratto <robertfratto@gmail.com>

Co-authored-by: SriKrishna Paparaju <paparaju@gmail.com>
2021-10-29 16:25:05 +01:00
beorn7 a9008f5423 Merge branch 'main' into sparsehistogram 2021-10-19 17:14:23 +02:00
Paweł Szulik 4414351576
web api: Delete unnecessary conversion. (#9517) 2021-10-15 18:41:53 -04:00
beorn7 fd5ea4e0b5 Merge branch 'main' into sparsehistogram 2021-10-07 23:16:42 +02:00
Levi Harrison 70f597b033
Configure Scrape Interval and Timeout Via Relabeling (#8911)
* Configure scrape interval and timeout with labels

Signed-off-by: Levi Harrison <git@leviharrison.dev>
2021-08-31 17:37:32 +02:00
Ganesh Vernekar 1315d8ecb6
Remove query hacks in the API and fix metrics (#9275)
* Remove query hacks in the API and fix metrics

Signed-off-by: Ganesh Vernekar <ganeshvern@gmail.com>

* Tests for the metrics

Signed-off-by: Ganesh Vernekar <ganeshvern@gmail.com>

* Better way to count series on restart

Signed-off-by: Ganesh Vernekar <ganeshvern@gmail.com>
2021-08-31 17:01:19 +05:30
Ganesh Vernekar 8b70e87ab9
Merge remote-tracking branch 'upstream/main' into sparse-refactor
Signed-off-by: Ganesh Vernekar <ganeshvern@gmail.com>
2021-08-05 12:16:08 +05:30
Oleg Zaytsev b1ed4a0a66
LabelNames API with matchers (#9083)
* Push the matchers for LabelNames all the way into the index.

NB This doesn't actually implement it in the index, just plumbs it through for now...

Signed-off-by: Tom Wilkie <tom@grafana.com>

* Hack it up.  Does not work.

Signed-off-by: Tom Wilkie <tom@grafana.com>

* Revert changes I don't understand

Can't see why do we need to hold a mutex on symbols, and the purpose of
the LabelNamesFor method.

Maybe I'll need to re-add this later.

Signed-off-by: Oleg Zaytsev <mail@olegzaytsev.com>

* Implement LabelNamesFor

This method provides the label names that appear in the postings
provided. We do that deeper than the label values because we know
beforehand that most of the label names we'll be the same across
different postings, and we don't want to go down an up looking up the
same symbols for all different series.

Signed-off-by: Oleg Zaytsev <mail@olegzaytsev.com>

* Mutex on symbols should be unlocked

However, I still don't understand why do we need a mutex here.

Signed-off-by: Oleg Zaytsev <mail@olegzaytsev.com>

* Fix head.LabelNamesFor

Signed-off-by: Oleg Zaytsev <mail@olegzaytsev.com>

* Implement mockIndex LabelNames with matchers

Signed-off-by: Oleg Zaytsev <mail@olegzaytsev.com>

* Nitpick on slice initialisation

Signed-off-by: Oleg Zaytsev <mail@olegzaytsev.com>

* Add tests for LabelNamesWithMatchers

Signed-off-by: Oleg Zaytsev <mail@olegzaytsev.com>

* Fix the mutex mess on head.LabelValues/LabelNames

I still don't see why we need to grab that unrelated mutex, but at least
now we're grabbing it consistently

Signed-off-by: Oleg Zaytsev <mail@olegzaytsev.com>

* Check error after iterating postings

Signed-off-by: Oleg Zaytsev <mail@olegzaytsev.com>

* Use the error from posting when there was en error in postings

Co-authored-by: Ganesh Vernekar <15064823+codesome@users.noreply.github.com>
Signed-off-by: Oleg Zaytsev <mail@olegzaytsev.com>

* Update storage/interface.go comment

Signed-off-by: Oleg Zaytsev <mail@olegzaytsev.com>

Co-authored-by: Ganesh Vernekar <15064823+codesome@users.noreply.github.com>

* Update tsdb/index/index.go comment

Signed-off-by: Oleg Zaytsev <mail@olegzaytsev.com>

Co-authored-by: Ganesh Vernekar <15064823+codesome@users.noreply.github.com>

* Update tsdb/index/index.go wrapped error msg

Signed-off-by: Oleg Zaytsev <mail@olegzaytsev.com>

Co-authored-by: Ganesh Vernekar <15064823+codesome@users.noreply.github.com>

* Update tsdb/index/index.go wrapped error msg

Signed-off-by: Oleg Zaytsev <mail@olegzaytsev.com>

Co-authored-by: Ganesh Vernekar <15064823+codesome@users.noreply.github.com>

* Update tsdb/index/index.go warpped error msg

Signed-off-by: Oleg Zaytsev <mail@olegzaytsev.com>

Co-authored-by: Ganesh Vernekar <15064823+codesome@users.noreply.github.com>

* Remove unneeded comment

Signed-off-by: Oleg Zaytsev <mail@olegzaytsev.com>

* Add testcases for LabelNames w/matchers in api.go

Signed-off-by: Oleg Zaytsev <mail@olegzaytsev.com>

* Use t.Cleanup() instead of defer in tests

Signed-off-by: Oleg Zaytsev <mail@olegzaytsev.com>

Co-authored-by: Tom Wilkie <tom@grafana.com>
Co-authored-by: Ganesh Vernekar <15064823+codesome@users.noreply.github.com>
2021-07-20 18:08:08 +05:30
Ganesh Vernekar 4cb4fe44f2
Hardcode rate() for sparse histograms
Signed-off-by: Ganesh Vernekar <ganeshvern@gmail.com>
2021-07-05 16:17:34 +05:30
Ganesh Vernekar 4c01ff5194
Bunch of fixes for sparse histograms (#9043)
* Do not panic on histoAppender.Append

Signed-off-by: Ganesh Vernekar <ganeshvern@gmail.com>

* M-map all chunks on shutdown

Signed-off-by: Ganesh Vernekar <ganeshvern@gmail.com>

* Support negative schema for querying

Signed-off-by: Ganesh Vernekar <ganeshvern@gmail.com>
2021-07-03 23:04:34 +05:30
Ganesh Vernekar 78d68d5972
Make query_range serve histograms (#9036)
* Modify query_range to serve only sparse histograms

Signed-off-by: Ganesh Vernekar <ganeshvern@gmail.com>

* Finish CumulativeExpandSparseHistogram for positive schema

Signed-off-by: Ganesh Vernekar <ganeshvern@gmail.com>

* Fix lint

Signed-off-by: Ganesh Vernekar <ganeshvern@gmail.com>

* Fix bug and comment out tests for query_range

Signed-off-by: Ganesh Vernekar <ganeshvern@gmail.com>

* Fix lint 2

Signed-off-by: Ganesh Vernekar <ganeshvern@gmail.com>
2021-07-03 19:23:56 +05:30
Levi Harrison b5f6f8fb36 Switched to go-kit/log
Signed-off-by: Levi Harrison <git@leviharrison.dev>
2021-06-11 12:28:36 -04:00
Levi Harrison 7bc11dcb06
React UI: Add Starting Screen (#8662)
* Added walreplay API endpoint

Signed-off-by: Levi Harrison <git@leviharrison.dev>

* Added starting page to react-ui

Signed-off-by: Levi Harrison <git@leviharrison.dev>

* Documented the new endpoint

Signed-off-by: Levi Harrison <git@leviharrison.dev>

* Fixed typos

Signed-off-by: Levi Harrison <git@leviharrison.dev>

Co-authored-by: Julius Volz <julius.volz@gmail.com>

* Removed logo

Signed-off-by: Levi Harrison <git@leviharrison.dev>

* Changed isResponding to isUnexpected

Signed-off-by: Levi Harrison <git@leviharrison.dev>

* Changed width of progress bar

Signed-off-by: Levi Harrison <git@leviharrison.dev>

* Changed width of progress bar

Signed-off-by: Levi Harrison <git@leviharrison.dev>

* Added DB stats object

Signed-off-by: Levi Harrison <git@leviharrison.dev>

* Updated starting page to work with new fields

Signed-off-by: Levi Harrison <git@leviharrison.dev>

* Passing nil

Signed-off-by: Levi Harrison <git@leviharrison.dev>

* Passing nil (pt. 2)

Signed-off-by: Levi Harrison <git@leviharrison.dev>

* Passing nil (pt. 3)

Signed-off-by: Levi Harrison <git@leviharrison.dev>

* Passing nil (and also implementing a method this time) (pt. 4)

Signed-off-by: Levi Harrison <git@leviharrison.dev>

* Passing nil (and also implementing a method this time) (pt. 5)

Signed-off-by: Levi Harrison <git@leviharrison.dev>

* Changed const to let

Signed-off-by: Levi Harrison <git@leviharrison.dev>

* Passing nil (pt. 6)

Signed-off-by: Levi Harrison <git@leviharrison.dev>

* Remove SetStats method

Signed-off-by: Levi Harrison <git@leviharrison.dev>

* Added comma

Signed-off-by: Levi Harrison <git@leviharrison.dev>

* Changed api

Signed-off-by: Levi Harrison <git@leviharrison.dev>

* Changed to triple equals

Signed-off-by: Levi Harrison <git@leviharrison.dev>

* Fixed data response types

Signed-off-by: Levi Harrison <git@leviharrison.dev>

* Don't return pointer

Signed-off-by: Levi Harrison <git@leviharrison.dev>

* Changed version

Signed-off-by: Levi Harrison <git@leviharrison.dev>

* Fixed interface issue

Signed-off-by: Levi Harrison <git@leviharrison.dev>

* Fixed pointer

Signed-off-by: Levi Harrison <git@leviharrison.dev>

* Fixed copying lock value error

Signed-off-by: Levi Harrison <git@leviharrison.dev>

Co-authored-by: Julius Volz <julius.volz@gmail.com>
2021-06-05 15:29:32 +01:00
Callum Styan 289ba11b79
Add circular in-memory exemplars storage (#6635)
* Add circular in-memory exemplars storage

Signed-off-by: Callum Styan <callumstyan@gmail.com>
Signed-off-by: Tom Wilkie <tom.wilkie@gmail.com>
Signed-off-by: Ganesh Vernekar <cs15btech11018@iith.ac.in>
Signed-off-by: Martin Disibio <mdisibio@gmail.com>

Co-authored-by: Ganesh Vernekar <cs15btech11018@iith.ac.in>
Co-authored-by: Tom Wilkie <tom.wilkie@gmail.com>
Co-authored-by: Martin Disibio <mdisibio@gmail.com>

* Fix some comments, clean up exemplar metrics struct and exemplar tests.

Signed-off-by: Callum Styan <callumstyan@gmail.com>

* Fix exemplar query api null vs empty array issue.

Signed-off-by: Callum Styan <callumstyan@gmail.com>

Co-authored-by: Ganesh Vernekar <cs15btech11018@iith.ac.in>
Co-authored-by: Tom Wilkie <tom.wilkie@gmail.com>
Co-authored-by: Martin Disibio <mdisibio@gmail.com>
2021-03-16 15:17:45 +05:30