1.1.0 / 2019-08-01

• [CHANGE] API client: Format time as UTC rather than RFC3339Nano. #617
• [CHANGE] API client: Add warnings to LabelValues and LabelNames calls. #609
• [FEATURE] Push: Support base64 encoding in grouping key. #624
• [FEATURE] Push: Add Delete method to Pusher. #613

1.0.0 / 2019-06-15

This release removes all previously deprecated features, resulting in the breaking changes listed below. As this is v1.0.0, semantic versioning applies from now on, with the exception of the API client and parts marked explicitly as experimental.

• [CHANGE] Remove objectives from the default Summary. (Objectives have to be set explicitly in the SummaryOpts.) #600
• [CHANGE] Remove all HTTP related feature in the prometheus package. (Use the promhttp package instead.) #600
• [CHANGE] Remove push.FromGatherer, push.AddFromGatherer, push.Collectors. (Use push.New instead.) #600
• [CHANGE] API client: Pass warnings through on non-error responses. #599
• [CHANGE] API client: Add warnings to Series call. #603
• [FEATURE] Make process collector work on Microsoft Windows. EXPERIMENTAL #596
• [FEATURE] API client: Add /labels call. #604
• [BUGFIX] Make AlreadyRegisteredError usable for wrapped registries. #607

0.9.4 / 2019-06-07

• [CHANGE] API client: Switch to alert values as strings. #585
• [FEATURE] Add a collector for Go module build information. #595
• [FEATURE] promhttp: Add an counter for internal errors during HTTP exposition. #594
• [FEATURE] API client: Support target metadata API. #590
• [FEATURE] API client: Support storage warnings. #562
• [ENHANCEMENT] API client: Improve performance handling JSON. #570
• [BUGFIX] Reduce test flakiness. #573

0.9.3 / 2019-05-16

• [CHANGE] Required Go version is now 1.9+. #561
• [FEATURE] API client: Add POST with get fallback for Query/QueryRange. #557
• [FEATURE] API client: Add alerts endpoint. #552
• [FEATURE] API client: Add rules endpoint. #508
• [FEATURE] push: Add option to pick metrics format. #540
• [ENHANCEMENT] Limit time the Go collector may take to collect memstats,
  returning results from the previous collection in case of a timeout. #568
• [ENHANCEMENT] Pusher now requires only a thin interface instead of a full
  http.Client, facilitating mocking and custom HTTP client implementation.
  #559
• [ENHANCEMENT] Memory usage improvement for histograms and summaries without
  objectives. #536
• [ENHANCEMENT] Summaries without objectives are now lock-free. #521
• [BUGFIX] promhttp: InstrumentRoundTripperTrace now takes into account a pre-set context. #582
• [BUGFIX] TestCounterAddLarge now works on all platforms. #567
• [BUGFIX] Fix promhttp examples. #535 #544
• [BUGFIX] API client: Wait for done before writing to shared response
  body. #532
• [BUGFIX] API client: Deal with discovered labels properly. #529

0.9.2 / 2018-12-06

• [FEATURE] Support for Go modules. #501
• [FEATURE] Timer.ObserveDuration returns observed duration. #509
• [ENHANCEMENT] Improved doc comments and error messages. #504
• [BUGFIX] Fix race condition during metrics gathering. #512
• [BUGFIX] Fix testutil metric comparison for Histograms and empty labels. #494 #498

0.9.1 / 2018-11-03

• [FEATURE] Add WriteToTextfile function to facilitate the creation of
  *.prom files for the textfile collector of the node exporter. #489
• [ENHANCEMENT] More descriptive error messages for inconsistent label
  cardinality. #487
• [ENHANCEMENT] Exposition: Use a GZIP encoder pool to avoid allocations in
  high-frequency scrape scenarios. #366
• [ENHANCEMENT] Exposition: Streaming serving of metrics data while encoding.
  #482
• [ENHANCEMENT] API client: Add a way to return the body of a 5xx response.
  #479

0.9.0 / 2018-10-15

• [CHANGE] Go1.6 is no longer supported.
• [CHANGE] More refinements of the Registry consistency checks: Duplicated
  labels are now detected, but inconsistent label dimensions are now allowed.
  Collisions with the “magic” metric and label names in Summaries and
  Histograms are detected now. #108 #417 #471
• [CHANGE] Changed ProcessCollector constructor. #219
• [CHANGE] Changed Go counter go_memstats_heap_released_bytes_total to gauge
  go_memstats_heap_released_bytes. #229
• [CHANGE] Unexported LabelPairSorter. #453
• [CHANGE] Removed the Untyped metric from direct instrumentation. #340
• [CHANGE] Unexported MetricVec. #319
• [CHANGE] Removed deprecated Set method from Counter #247
• [CHANGE] Removed deprecated RegisterOrGet and MustRegisterOrGet. #247
• [CHANGE] API client: Introduced versioned packages.
• [FEATURE] A Registerer can be wrapped with prefixes and labels. #357
• [FEATURE] “Describe by collect” helper function. #239
• [FEATURE] Added package testutil. #58
• [FEATURE] Timestamp can be explicitly set for const metrics. #187
• [FEATURE] “Unchecked” collectors are possible now without cheating. #47
• [FEATURE] Pushing to the Pushgateway reworked in package push to support
  many new features. (The old functions are still usable but deprecated.) #372
  #341
• [FEATURE] Configurable connection limit for scrapes. #179
• [FEATURE] New HTTP middlewares to instrument http.Handler and
  http.RoundTripper. The old middlewares and the pre-instrumented /metrics
  handler are (strongly) deprecated. #316 #57 #101 #224
• [FEATURE] “Currying” for metric vectors. #320
• [FEATURE] A Summary can be created without quantiles. #118
• [FEATURE] Added a Timer helper type. #231
• [FEATURE] Added a Graphite bridge. #197
• [FEATURE] Help strings are now optional. #460
• [FEATURE] Added process_virtual_memory_max_bytes metric. #438 #440
• [FEATURE] Added go_gc_cpu_fraction and go_threads metrics. #281 #277
• [FEATURE] Added promauto package with auto-registering metrics. #385 #393
• [FEATURE] Add SetToCurrentTime method to Gauge. #259
• [FEATURE] API client: Add AlertManager, Status, and Target methods. #402
• [FEATURE] API client: Add admin methods. #398
• [FEATURE] API client: Support series API. #361
• [FEATURE] API client: Support querying label values.
• [ENHANCEMENT] Smarter creation of goroutines during scraping. Solves memory
  usage spikes in certain situations. #369
• [ENHANCEMENT] Counters are now faster if dealing with integers only. #367
• [ENHANCEMENT] Improved label validation. #274 #335
• [BUGFIX] Creating a const metric with an invalid Desc returns an error. #460
• [BUGFIX] Histogram observations don't race any longer with exposition. #275
• [BUGFIX] Fixed goroutine leaks. #236 #472
• [BUGFIX] Fixed an error message for exponential histogram buckets. #467
• [BUGFIX] Fixed data race writing to the metric map. #401
• [BUGFIX] API client: Decode JSON on a 4xx respons but do not on 204
  responses. #476 #414

0.8.0 / 2016-08-17

• [CHANGE] Registry is doing more consistency checks. This might break
  existing setups that used to export inconsistent metrics.
• [CHANGE] Pushing to Pushgateway moved to package push and changed to allow
  arbitrary grouping.
• [CHANGE] Removed SelfCollector.
• [CHANGE] Removed PanicOnCollectError and EnableCollectChecks methods.
• [CHANGE] Moved packages to the prometheus/common repo: text, model,
  extraction.
• [CHANGE] Deprecated a number of functions.
• [FEATURE] Allow custom registries. Added Registerer and Gatherer
  interfaces.
• [FEATURE] Separated HTTP exposition, allowing custom HTTP handlers (package
  promhttp) and enabling the creation of other exposition mechanisms.
• [FEATURE] MustRegister is variadic now, allowing registration of many
  collectors in one call.
• [FEATURE] Added HTTP API v1 package.
• [ENHANCEMENT] Numerous documentation improvements.
• [ENHANCEMENT] Improved metric sorting.
• [ENHANCEMENT] Inlined fnv64a hashing for improved performance.
• [ENHANCEMENT] Several test improvements.
• [BUGFIX] Handle collisions in MetricVec.

0.7.0 / 2015-07-27

• [CHANGE] Rename ExporterLabelPrefix to ExportedLabelPrefix.
• [BUGFIX] Closed gaps in metric consistency check.
• [BUGFIX] Validate LabelName/LabelSet on JSON unmarshaling.
• [ENHANCEMENT] Document the possibility to create "empty" metrics in
  a metric vector.
• [ENHANCEMENT] Fix and clarify various doc comments and the README.md.
• [ENHANCEMENT] - (Kind of) solve "The Proxy Problem" of http.InstrumentHandler.
• [ENHANCEMENT] Change responseWriterDelegator.written to int64.

0.6.0 / 2015-06-01

• [CHANGE] Rename process_goroutines to go_goroutines.
• [ENHANCEMENT] Validate label names during YAML decoding.
• [ENHANCEMENT] Add LabelName regular expression.
• [BUGFIX] Ensure alignment of struct members for 32-bit systems.