Add prometheus bridge #4227
Add prometheus bridge #4227
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## main #4227 +/- ##
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Coverage 82.1% 82.2%
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Files 142 144 +2
Lines 9818 10005 +187
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+ Hits 8067 8229 +162
- Misses 1617 1636 +19
- Partials 134 140 +6
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I've addressed open comments on the original PR. |
dashpole
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Is there not a summary metric type in OTLP for exactly that reason? Or is it missing in the Go SDK data model? |
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It is missing in the Go SDK data model. Adding it to the data model would mean in-process exporters would have to handle summary-typed metrics. But maybe it is better to add it, and expect most exporters other than OTLP to drop it... |
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Got it! |
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Rebased. I think this is good to go |
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I just left some comments for the documentation. Reference: https://github.com/open-telemetry/opentelemetry-go/blob/main/CONTRIBUTING.md#documentation
@dashpole let me know if you want me to merge this PR as it is.
| * Summary metrics are dropped by the bridge. | ||
| * Start times for histograms and counters are set to the process start time. | ||
| * It does not currently support exponential histograms. |
| ## Usage | ||
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| ```golang | ||
| // Make a Promethes bridge "Metric Producer" that adds metrics from the | ||
| // Prometheus DefaultGatherer. Add the WithGatherer(registry) option to add | ||
| // metrics from other registries. | ||
| bridge := prometheus.NewMetricProducer() | ||
| // Make a Periodic Reader to periodically gather metrics from the bridge, and | ||
| // push to an OpenTelemetry exporter. | ||
| reader := metric.NewPeriodicReader(otelExporter, metric.WithProducer(bridge)) | ||
| // Create an OTel MeterProvider with our reader. Metrics from OpenTelemetry | ||
| // instruments are combined with metrics from Prometheus instruments in | ||
| // exported batches of metrics. | ||
| mp := metric.NewMeterProvider(metric.WithReader(reader)) | ||
| ``` |
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We can make a "testable example" in example_test.go instead.
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I think we can get rid of this file in favor of doc.go and example_test.go.
| The Prometheus Bridge allows using the Prometheus Golang client library | ||
| (github.com/prometheus/client_golang) with the OpenTelemetry SDK. |
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I'd prefer to merge as-is. I'll open a follow-up with the new docs. |
Migrated from open-telemetry/opentelemetry-go#4351
This allows applications instrumented with the prometheus client library to use OpenTelemetry exporters (e.g. OTLP).
Limitations:
Despite the limitations, I think this still has a lot of value to users.