- [Fix] zipper requests net error (encapsulated) (thx to @msaf1980)

- [Fix] preserve original points for some functions (thx to @msaf1980)
- [Fix] aliasByNode: strip function in name (thx to @msaf1980)
- [Improvement] build: allow to replace fpm with cli-compability program (thx to @msaf1980)
- [Improvement] build: equal version for carbonapi/carbonzipper package (thx to @msaf1980)

 - [Fix] Time parsing is now closer to how graphite do it

 - [Fix] Aggregation functions now scale input to common step (thx to @Felixoid)
 - [Fix] Fix the way how partialy retrived requests that had globs were handled
 - [Fix] Fix resolver to accept `0.0.0.0` and `[::]` as valid addresses for listeners
 - [Fix] Handling of unicode characters when common table is added.
 - [Fix] AlignVluaes in Prometheus and VictoriaMetrics backends shouldn't drop last value (thx to @limpasha)
 - [Fix] maxDataPoints should be passed to Prometheus and VictoriaMetrics\
 - [Fix] Various packaging problems (e.x. logrotate) (thx to @deniszh)
 - [Improvement] xFilesFactor support in SUmmarizeValues
 - [Improvement] Port functions that were implemented in avito's fork of carbonapi (aliasByHash, lowestMin, highestMin, integralWithReset and much more): go-graphite@322dae5 for the diff for COMPATIBILITY.md file
 - [Improvement] Refactor error handling (thx to @msaf1980)
 - [Improvement] Default systemd unit should drop privileges (thx to @deniszh)
 - [Improvement] Enable cairo support for docker images (thx to @deniszh)

0.15.0

 - **[Breaking]** - cache (including memcache) now uses sha256 for a hash function for keys. This might break existing setup
 - **[Breaking]** - new config variable `slowLogThreshold` under `upstreams` section controls what request time would be required for request to be logged in `slow` logger.
 - **[Breaking]** - remove semi-broken support for graceful restarts (See go-graphite#552)
 - [Fix] Fix parsing tags from backend replies (adds support of `=` in tag values, make them more compatible with graphite-web)
 - [Fix] Fix how request splitting worked for maxBatchSize != 0 (thx to @tantra35)
 - [Improvement] Bad requests will return error 400 instead of 500 (thx to @Felixoid)
 - [Improvement] VictoriaMetrics >= 1.53.1 backend should work a bit faster for find queries
 - [Improvement] Do not apply tag-deduplication for VictoriaMetrics >= 1.50.0 (less memory consumption, faster queries)
 - [Improvement] Use VictoriaMetrics's graphite-compatibe API to query for tags (less memory consumption, faster queres)
 - [Feature] Support `add` function (thx to @Felixoid)
 - [Feature] removeEmptySeries supports xFilesFactor parameter (thx to @faceair)
 - [Feature] Allow to specify multiple listen addresses
 - [Feature] Optional caching DNS resolver

 - [Fix] Fix test for timeShift function. This doesn't affect the way…

… how carbonapi works, just makes CI happy

 - [Feature] Separate backend protocol for VictoriaMetrics. Based on …

…prometheus protocol (and share some of it's code), but uses some of VM-specific features to improve performance for /metrics/find queries (Related to go-graphite#521)

 - [Feature] timeShift function supports `resetEnd` parameter (thx to @faceair). Current default is set to `false` to match carbonapi behavior, however in 0.15.0 it will be changed to `true`.
 - [Feature] Resepct pixelRatio parameter from referer if not specified in request. (thx to @lomik)
 - [Fix] Handling of maxBatchSize (maxGlobs) in config file. Respect overrides on backend level.
 - [Fix] Warnings about duplicate functions when carbonapi starts.
 - [Fix] Resulting tags in groupByTags are now correct (thx to @Felixoid)
 - [Fix] Fix handling of requests that fetches data with different start/end times (thx to @Felixoid). Related to go-graphite#526
 - [Fix] Fix the way how `pow` function works with NaN in values (thx to @zhelyabuzhsky)
 - [Fix] CSV format now produce dates in UTC (like in graphite-web) (thx to @jonasbleyl)
 - [Fix] Fix from/util timestamp aligning in all moving* functions (thx to @Felixoid)

 - [Feature] Implement `doMultipleRequestsIfSplit` config option whic…

…h could be useful for go-carbon and huge requests (See go-graphite#509)

 - [Improvement] Return stacktrace on panic (thx to @Felixoid)
 - [Fix] Fix case where some metrics passed to functions like group or sumSeries were missing. Fixes go-graphite#438
 - [Fix] Accept `1` and `0` as bool arguments for `True` and `False`. (thx to @Felixoid)
 - [Fix] Align precision of multiple metrics (thx to @Felixoid, see go-graphite#500 and go-graphite#501)
 - [Fix] fallbackSeries now works properly (thx to @egor Redozubov)
 - [Fix] Panic when trying to render png/svg of an empty response (Fixes go-graphite#503)
 - [Fix] Fix Error 500 when sendGlobsAsIs is false (Fixes go-graphite#506)
 - [Fix] prometheus backend: carbonapi should send 'end' instead of 'stop' in queries (thx to Alexandre Vincent)
 - [Fix] change metrics resulting tags to match graphite-web in some cases (thx to @Felixoid)
 - [Fix] Prometheus backend: trust timestamps from the backend (Fixes go-graphite#504, Fixes go-graphite#514)
 - [Fix] percentileOfSeries: return first of filtered datapoints in case only one series have valid data (Fixes go-graphite#516)
 - [Code] merge aliasByNode and aliasByTags (thx to @Felixoid)

 - **[Breaking]**[Code] expr library and all functions now requires c…

…aller to pass context. See go-graphite#485

 - **[Breaking]**[Config] for protocol `auto` there is now no default implied concurrency limit of `100` as it was before.
 - **[Breaking]**[Config] Changed default value for `notFoundStatusCode` to 200 to match graphite-web behavior
 - [Feature] Add a `backendCache` option that implements dedicated cache for backend responses. See go-graphite#480 (thx to @jaroslawr)
 - [Feature] For Prometheus backend it is now possible to specify max\_points\_per\_query
 - [Feature] weightedAverage function (thx to @Felixoid)
 - [Improvement] carbonapi now pass maxDataPoints to backends that support carbonapi\_v3\_pb format. Previously 0 was passed.
 - [Fix] metric find requests to backend now pass start and end time (thx to @faceair)
 - [Fix] Fix 404 status code if backend have errors (thx to @lexx-bright)
 - [Fix] Fix sorting in \*seriesLists functions (thx to Egor Redozubov)
 - [Fix] Potential panic during groupByNode evaluation if callback is invalid expression
 - [Fix] Partially overlapping backend groups caused some queries to return empty result
 - [Fix] Sorting metrics should work now in the same way as in graphite-web (thx to @Felixoid)
 - [Fix] Time of the first timestamp was wrong if multiplySeries was applied (it matched request `from`)

0.13.0

 - [Fix] smartSummarize now supports wildcards in the metric names (thx to @Peter-Sh)
 - [Fix] json format correctly distinguishes between +-inf and nan (thx to @faceair)
 - [Fix] prometheus backend: fix a bunch of problems related to globs and regex escaping (thx to @rodio)
 - [Fix] Proper fix for prometheus backend and non-taged render requests with groupByNodes function
 - [Fix] Align timestamps in prometheus backend (thx to @rodio, go-graphite#467)
 - [Fix] Prometheus backend wasn't working correctly for non-taged render requests (go-graphite#465, thx to @menai34 for proposed fix)
 - [Fix] Fix panic when using prometheus tagged response for non-tagged queries in groupByTags function (and maybe more)
 - [Fix] Add proper aliases for `aggregate` functions - that would make groupByTags properly usable with functions like `diff` and `total`.
 - [Improvement] Redesign error handling and logging. Logging should be now less noisy and all error messages should contain better reasoning about error cause
 - [Improvement] Move some of the logging messages to Debug level - that should make logs less noisy and still preserve ability to see detailed errors on Debug level
 - [Improvement] Add a config parameter to disable tldCache (useful for clickhouse-based backends)
 - [Improvement] Implement noNullPoints query parameter. Works only with JSON as in graphite-web
 - [Improvement] For all SeriesLists functions, allow to specify default argument (thx to kolobaev@)
 - [Improvement] Add support for `round` function (thx to kolobaev@)
 - [Improvement] Add integralByInterval function (thx to faceair@)
 - [Improvement] Add sortBy function (thx to misiek08@)
 - [Improvement] Add smartSummarize function (thx to misiek08@)
 - [Fix] /render and /metrics/find URLs now works correctly for format=carbonapi\_v2\_pb (protov3) and for new format (carbonapi as a carbonapi's backend)
 - [Fix] Allow '%' in metric names
 - [Fix] zipper metrics now exported again
 - [Fix] applyByNode - fix various incompatibilities with graphite-web (node starts with 1, some rewrite related issues, etc) (thx to faceair@)
 - [Fix] Honor SendGlobAsIs and AlwaysSendGlobAsIs (important for pre-0.12 configs)
 - [Fix] Fix panic in some cases when one of the metrics is missing
 - [Fix] Compatbility fixes to useAboveSeries (now it's behavior matches graphite-web's)
 - [Fix] Fix seriesList functions in case of unsorted responses (\*seriesList sorts denomniators and numerators first of all)
 - [Fix] Fix pprof endpoint routing (thx to faceair@)
 - [Fix] Various fixes around error handling (thx to faceair@)
 - [Fix] Avoid multiple requests for time moving based functions (thx to faceair@)
 - [Code] Make linters much more happier about the code (thx to faceair@ for contribution)
 - **[Breaking]** [Code] Comment out support for gRPC backend type. It was never properly tested and likely need complete rework before it will be usable
 - **[Breaking]** [Build] Minimum Supported golang version is 1.13.0