Add OTel HTTP support

core-api/src/telemetry.rs

@@ -71,6 +71,9 @@ pub struct OtelCollectorOptions {
     /// Overrides for histogram buckets. Units depend on the value of `use_seconds_for_durations`.
     #[builder(default)]
     pub histogram_bucket_overrides: HistogramBucketOverrides,
+    /// Protocol to use for communication with the collector
+    #[builder(default = "OtlpProtocl::Grpc")]
+    pub protocol: OtlpProtocl,
 }
 
 /// Options for exporting metrics to Prometheus
@@ -143,6 +146,15 @@ pub enum MetricTemporality {
     Delta,
 }
 
+/// Options for configuring telemetry
+#[derive(Debug, Clone, Copy)]
+pub enum OtlpProtocl {
+    /// Use gRPC to communicate with the collector
+    Grpc,
+    /// Use HTTP to communicate with the collector
+    Http,
+}
+
 impl Default for TelemetryOptions {
     fn default() -> Self {
         TelemetryOptionsBuilder::default().build().unwrap()

core/Cargo.toml

@@ -44,7 +44,7 @@ lru = "0.12"
 mockall = "0.13"
 opentelemetry = { workspace = true, features = ["metrics"], optional = true }
 opentelemetry_sdk = { version = "0.26", features = ["rt-tokio", "metrics"], optional = true }
-opentelemetry-otlp = { version = "0.26", features = ["tokio", "metrics", "tls"], optional = true }
+opentelemetry-otlp = { version = "0.26", features = ["tokio", "metrics", "tls", "http-proto"], optional = true }
 opentelemetry-prometheus = { git = "https://github.com/open-telemetry/opentelemetry-rust.git", rev = "e911383", optional = true }
 parking_lot = { version = "0.12", features = ["send_guard"] }
 pid = "4.0"

core/src/telemetry/otel.rs

@@ -30,7 +30,8 @@ use temporal_sdk_core_api::telemetry::{
         CoreMeter, Counter, Gauge, GaugeF64, Histogram, HistogramDuration, HistogramF64,
         MetricAttributes, MetricParameters, NewAttributes,
     },
-    HistogramBucketOverrides, MetricTemporality, OtelCollectorOptions, PrometheusExporterOptions,
+    HistogramBucketOverrides, MetricTemporality, OtelCollectorOptions, OtlpProtocl,
+    PrometheusExporterOptions,
 };
 use tokio::task::AbortHandle;
 use tonic::{metadata::MetadataMap, transport::ClientTlsConfig};
@@ -120,16 +121,26 @@ pub(super) fn augment_meter_provider_with_defaults(
 pub fn build_otlp_metric_exporter(
     opts: OtelCollectorOptions,
 ) -> Result<CoreOtelMeter, anyhow::Error> {
-    let mut exporter =
-        opentelemetry_otlp::TonicExporterBuilder::default().with_endpoint(opts.url.to_string());
-    if opts.url.scheme() == "https" || opts.url.scheme() == "grpcs" {
-        exporter = exporter.with_tls_config(ClientTlsConfig::new().with_native_roots());
-    }
-    let exporter = exporter
-        .with_metadata(MetadataMap::from_headers((&opts.headers).try_into()?))
-        .build_metrics_exporter(Box::new(metric_temporality_to_selector(
-            opts.metric_temporality,
-        )))?;
+    let exporter = match opts.protocol {
+        OtlpProtocl::Grpc => {
+            let mut exporter = opentelemetry_otlp::TonicExporterBuilder::default()
+                .with_endpoint(opts.url.to_string());
+            if opts.url.scheme() == "https" || opts.url.scheme() == "grpcs" {
+                exporter = exporter.with_tls_config(ClientTlsConfig::new().with_native_roots());
+            }
+            exporter
+                .with_metadata(MetadataMap::from_headers((&opts.headers).try_into()?))
+                .build_metrics_exporter(Box::new(metric_temporality_to_selector(
+                    opts.metric_temporality,
+                )))?
+        }
+        OtlpProtocl::Http => opentelemetry_otlp::HttpExporterBuilder::default()
+            .with_endpoint(opts.url.to_string())
+            .with_headers(opts.headers)
+            .build_metrics_exporter(Box::new(metric_temporality_to_selector(
+                opts.metric_temporality,
+            )))?,
+    };
     let reader = PeriodicReader::builder(exporter, runtime::Tokio)
         .with_interval(opts.metric_periodicity)
         .build();