| _(If you are reading this because you are interested in Prometheus's native |
| histograms, pay special attention to the last paragraph below.)_ |
| |
| # Deprecation note |
| |
| This repository used to contain the [protocol |
| buffer](https://developers.google.com/protocol-buffers) code that defined both |
| the data model and the exposition format of Prometheus metrics. |
| |
| Starting with v2.0.0, the [Prometheus |
| server](https://github.com/prometheus/prometheus) does not ingest the |
| protobuf-based exposition format anymore. Currently, all but one of the |
| [official instrumentation |
| libraries](https://prometheus.io/docs/instrumenting/clientlibs/) do not expose |
| the protobuf-based exposition format. The [Go instrumentation |
| library](https://github.com/prometheus/client_golang), however, has been built |
| around the protobuf-based data model. As a byproduct thereof, it is still able |
| to expose the protobuf-based exposition format. The Go instrumentation library |
| is the only remaining repository within the [Prometheus GitHub |
| org](https://github.com/prometheus) directly using the prometheus/client_model |
| repository. |
| |
| Therefore, formerly existing support for languages other than Go (namely C++, |
| Java, Python, Ruby) has been removed from this repository. If you are a 3rd |
| party user of those languages, you can go back to [commit |
| 14fe0d1](https://github.com/prometheus/client_model/commit/14fe0d1b01d4d5fc031dd4bec1823bd3ebbe8016) |
| to keep using the old code, or you can consume |
| [`metrics.proto`](https://github.com/prometheus/client_model/blob/master/metrics.proto) |
| directly with your own protobuf tooling. Note, however, that changes of |
| `metrics.proto` after [commit |
| 14fe0d1](https://github.com/prometheus/client_model/commit/14fe0d1b01d4d5fc031dd4bec1823bd3ebbe8016) |
| are solely informed by requirements of the Go instrumentation library and will |
| not take into account any requirements of other languages or stability concerns |
| for the protobuf-based exposition format. |
| |
| Check out the [OpenMetrics project](https://openmetrics.io/) for the future of |
| the data model and exposition format used by Prometheus and others. |
| |
| Note, though, that in an ironic twist of fate, the protobuf-based exposition |
| format got revived to suppert native histograms in Prometheus. Therefore, |
| starting with v2.40.0, the Prometheus server is again capable of ingesting the |
| protobuf-based exposition format. Eventually, native histogram support will be |
| added in some form to OpenMetrics, too. |
