From 5b4124948fd57e1a53be4fa3431b3dafb41fbb37 Mon Sep 17 00:00:00 2001
From: Parth Jindal <parth@askwisdom.ai>
Date: Sun, 12 Apr 2026 11:52:41 +0530
Subject: [PATCH] Expose histogram_bucket_overrides on OpenTelemetryConfig

Mirror the existing PrometheusConfig.histogram_bucket_overrides field.
The underlying OtelCollectorOptions builder already supports this via
maybe_histogram_bucket_overrides; this change wires it through the
Python wrapper and pyo3 bridge.
---
 temporalio/bridge/runtime.py     | 1 +
 temporalio/bridge/src/runtime.rs | 6 ++++++
 temporalio/runtime.py            | 6 ++++++
 3 files changed, 13 insertions(+)

diff --git a/temporalio/bridge/runtime.py b/temporalio/bridge/runtime.py
index fa7fb275d..87f03f9c3 100644
--- a/temporalio/bridge/runtime.py
+++ b/temporalio/bridge/runtime.py
@@ -71,6 +71,7 @@ class OpenTelemetryConfig:
     metric_temporality_delta: bool
     durations_as_seconds: bool
     http: bool
+    histogram_bucket_overrides: Mapping[str, Sequence[float]] | None = None
 
 
 @dataclass(frozen=True)
diff --git a/temporalio/bridge/src/runtime.rs b/temporalio/bridge/src/runtime.rs
index 94cf5a025..ef47317ef 100644
--- a/temporalio/bridge/src/runtime.rs
+++ b/temporalio/bridge/src/runtime.rs
@@ -75,6 +75,7 @@ pub struct OpenTelemetryConfig {
     metric_temporality_delta: bool,
     durations_as_seconds: bool,
     http: bool,
+    histogram_bucket_overrides: Option<HashMap<String, Vec<f64>>>,
 }
 
 #[derive(FromPyObject)]
@@ -357,6 +358,11 @@ impl TryFrom<MetricsConfig> for Arc<dyn CoreMeter> {
                 } else {
                     None
                 })
+                .maybe_histogram_bucket_overrides(otel_conf.histogram_bucket_overrides.map(
+                    |overrides| temporalio_common::telemetry::HistogramBucketOverrides {
+                        overrides,
+                    },
+                ))
                 .build();
             Ok(Arc::new(build_otlp_metric_exporter(otel_options).map_err(
                 |err| PyValueError::new_err(format!("Failed building OTel exporter: {err}")),
diff --git a/temporalio/runtime.py b/temporalio/runtime.py
index 8fab68e9e..3043372c3 100644
--- a/temporalio/runtime.py
+++ b/temporalio/runtime.py
@@ -335,6 +335,10 @@ class OpenTelemetryConfig:
             When enabled, the ``url`` should point to the HTTP endpoint
             (e.g. ``"http://localhost:4318/v1/metrics"``).
             Defaults to ``False`` (gRPC).
+        histogram_bucket_overrides: Override the default histogram bucket
+            boundaries for specific metrics. Keys are metric names and
+            values are sequences of bucket boundaries (e.g.
+            ``{"workflow_task_schedule_to_start_latency": [0.01, 0.05, 0.1, 0.5, 1.0, 5.0]}``).
     """
 
     url: str
@@ -345,6 +349,7 @@ class OpenTelemetryConfig:
     )
     durations_as_seconds: bool = False
     http: bool = False
+    histogram_bucket_overrides: Mapping[str, Sequence[float]] | None = None
 
     def _to_bridge_config(self) -> temporalio.bridge.runtime.OpenTelemetryConfig:
         return temporalio.bridge.runtime.OpenTelemetryConfig(
@@ -360,6 +365,7 @@ def _to_bridge_config(self) -> temporalio.bridge.runtime.OpenTelemetryConfig:
             ),
             durations_as_seconds=self.durations_as_seconds,
             http=self.http,
+            histogram_bucket_overrides=self.histogram_bucket_overrides,
         )