allow for multiple otel span processors & metric readers (#2623)

.changeset/metal-fireants-remember.md

@@ -0,0 +1,5 @@
+---
+"@effect/opentelemetry": patch
+---
+
+allow for multiple otel span processors & metric readers

packages/opentelemetry/src/Metrics.ts

@@ -2,6 +2,7 @@
  * @since 1.0.0
  */
 import type { MetricProducer, MetricReader } from "@opentelemetry/sdk-metrics"
+import type { NonEmptyReadonlyArray } from "effect/Array"
 import type * as Effect from "effect/Effect"
 import type { LazyArg } from "effect/Function"
 import type { Layer } from "effect/Layer"
@@ -21,11 +22,13 @@ export const makeProducer: Effect.Effect<MetricProducer, never, Resource> = inte
  */
 export const registerProducer: (
   self: MetricProducer,
-  metricReader: LazyArg<MetricReader>
-) => Effect.Effect<MetricReader, never, Scope.Scope> = internal.registerProducer
+  metricReader: LazyArg<MetricReader | NonEmptyReadonlyArray<MetricReader>>
+) => Effect.Effect<Array<any>, never, Scope.Scope> = internal.registerProducer
 
 /**
  * @since 1.0.0
  * @category layers
  */
-export const layer: (evaluate: LazyArg<MetricReader>) => Layer<never, never, Resource> = internal.layer
+export const layer: (
+  evaluate: LazyArg<MetricReader | NonEmptyReadonlyArray<MetricReader>>
+) => Layer<never, never, Resource> = internal.layer

packages/opentelemetry/src/NodeSdk.ts

@@ -6,6 +6,7 @@ import type * as Resources from "@opentelemetry/resources"
 import type { MetricReader } from "@opentelemetry/sdk-metrics"
 import type { SpanProcessor, TracerConfig } from "@opentelemetry/sdk-trace-base"
 import { NodeTracerProvider } from "@opentelemetry/sdk-trace-node"
+import type { NonEmptyReadonlyArray } from "effect/Array"
 import * as Effect from "effect/Effect"
 import type { LazyArg } from "effect/Function"
 import * as Layer from "effect/Layer"
@@ -18,9 +19,9 @@ import * as Tracer from "./Tracer.js"
  * @category model
  */
 export interface Configuration {
-  readonly spanProcessor?: SpanProcessor | undefined
+  readonly spanProcessor?: SpanProcessor | ReadonlyArray<SpanProcessor> | undefined
   readonly tracerConfig?: Omit<TracerConfig, "resource"> | undefined
-  readonly metricReader?: MetricReader | undefined
+  readonly metricReader?: MetricReader | ReadonlyArray<MetricReader> | undefined
   readonly resource?: {
     readonly serviceName: string
     readonly serviceVersion?: string
@@ -33,7 +34,7 @@ export interface Configuration {
  * @category layers
  */
 export const layerTracerProvider = (
-  processor: SpanProcessor,
+  processor: SpanProcessor | NonEmptyReadonlyArray<SpanProcessor>,
   config?: Omit<TracerConfig, "resource">
 ): Layer.Layer<TracerProvider, never, Resource.Resource> =>
   Layer.scoped(
@@ -47,7 +48,11 @@ export const layerTracerProvider = (
               ...(config ?? undefined),
               resource
             })
-            provider.addSpanProcessor(processor)
+            if (Array.isArray(processor)) {
+              processor.forEach((p) => provider.addSpanProcessor(p))
+            } else {
+              provider.addSpanProcessor(processor as any)
+            }
             return provider
           }),
           (provider) => Effect.ignoreLogged(Effect.promise(() => provider.shutdown()))
@@ -74,14 +79,16 @@ export const layer: {
         const ResourceLive = config.resource === undefined
           ? Resource.layerFromEnv()
           : Resource.layer(config.resource)
-        const TracerLive = config.spanProcessor ?
-          Tracer.layer.pipe(
-            Layer.provide(layerTracerProvider(config.spanProcessor, config.tracerConfig))
-          )
-          : Layer.empty
-        const MetricsLive = config.metricReader
-          ? Metrics.layer(() => config.metricReader!)
-          : Layer.empty
+        const TracerLive =
+          config.spanProcessor && !(Array.isArray(config.spanProcessor) && config.spanProcessor.length === 0) ?
+            Tracer.layer.pipe(
+              Layer.provide(layerTracerProvider(config.spanProcessor as any, config.tracerConfig))
+            )
+            : Layer.empty
+        const MetricsLive =
+          config.metricReader && !(Array.isArray(config.metricReader) && config.metricReader.length === 0)
+            ? Metrics.layer(() => config.metricReader as any)
+            : Layer.empty
         return Layer.merge(TracerLive, MetricsLive).pipe(
           Layer.provideMerge(ResourceLive)
         )

packages/opentelemetry/src/WebSdk.ts

@@ -6,6 +6,7 @@ import type * as Resources from "@opentelemetry/resources"
 import type { MetricReader } from "@opentelemetry/sdk-metrics"
 import type { SpanProcessor, TracerConfig } from "@opentelemetry/sdk-trace-base"
 import { WebTracerProvider } from "@opentelemetry/sdk-trace-web"
+import type { NonEmptyReadonlyArray } from "effect/Array"
 import * as Effect from "effect/Effect"
 import type { LazyArg } from "effect/Function"
 import * as Layer from "effect/Layer"
@@ -18,9 +19,9 @@ import * as Tracer from "./Tracer.js"
  * @category model
  */
 export interface Configuration {
-  readonly spanProcessor?: SpanProcessor
+  readonly spanProcessor?: SpanProcessor | ReadonlyArray<SpanProcessor> | undefined
   readonly tracerConfig?: Omit<TracerConfig, "resource">
-  readonly metricReader?: MetricReader
+  readonly metricReader?: MetricReader | ReadonlyArray<MetricReader> | undefined
   readonly resource: {
     readonly serviceName: string
     readonly serviceVersion?: string
@@ -33,7 +34,7 @@ export interface Configuration {
  * @category layers
  */
 export const layerTracerProvider = (
-  processor: SpanProcessor,
+  processor: SpanProcessor | NonEmptyReadonlyArray<SpanProcessor>,
   config?: Omit<TracerConfig, "resource">
 ): Layer.Layer<TracerProvider, never, Resource.Resource> =>
   Layer.scoped(
@@ -47,7 +48,11 @@ export const layerTracerProvider = (
               ...(config ?? undefined),
               resource
             })
-            provider.addSpanProcessor(processor)
+            if (Array.isArray(processor)) {
+              processor.forEach((p) => provider.addSpanProcessor(p))
+            } else {
+              provider.addSpanProcessor(processor as any)
+            }
             return provider
           }),
           (provider) => Effect.ignoreLogged(Effect.promise(() => provider.shutdown()))
@@ -72,12 +77,14 @@ export const layer: {
         : Effect.sync(evaluate),
       (config) => {
         const ResourceLive = Resource.layer(config.resource)
-        const TracerLive = config.spanProcessor ?
-          Tracer.layer.pipe(Layer.provide(layerTracerProvider(config.spanProcessor, config.tracerConfig)))
-          : Layer.effectDiscard(Effect.void)
-        const MetricsLive = config.metricReader
-          ? Metrics.layer(() => config.metricReader!)
-          : Layer.effectDiscard(Effect.void)
+        const TracerLive =
+          config.spanProcessor && !(Array.isArray(config.spanProcessor) && config.spanProcessor.length === 0) ?
+            Tracer.layer.pipe(Layer.provide(layerTracerProvider(config.spanProcessor as any, config.tracerConfig)))
+            : Layer.effectDiscard(Effect.void)
+        const MetricsLive =
+          config.metricReader && !(Array.isArray(config.metricReader) && config.metricReader.length === 0)
+            ? Metrics.layer(() => config.metricReader as any)
+            : Layer.effectDiscard(Effect.void)
         return Layer.merge(TracerLive, MetricsLive).pipe(
           Layer.provideMerge(ResourceLive)
         )

packages/opentelemetry/src/internal/metrics.ts

@@ -290,18 +290,27 @@ export const makeProducer = Effect.map(
 )
 
 /** @internal */
-export const registerProducer = (self: MetricProducer, metricReader: LazyArg<MetricReader>) =>
+export const registerProducer = (
+  self: MetricProducer,
+  metricReader: LazyArg<MetricReader | Arr.NonEmptyReadonlyArray<MetricReader>>
+) =>
   Effect.acquireRelease(
     Effect.sync(() => {
       const reader = metricReader()
-      reader.setMetricProducer(self)
-      return reader
+      const readers: Array<MetricReader> = Array.isArray(reader) ? reader : [reader] as any
+      readers.forEach((reader) => reader.setMetricProducer(self))
+      return readers
     }),
-    (reader) => Effect.ignoreLogged(Effect.promise(() => reader.shutdown()))
+    (readers) =>
+      Effect.ignoreLogged(Effect.promise(() =>
+        Promise.all(
+          readers.map((reader) => reader.shutdown())
+        )
+      ))
   )
 
 /** @internal */
-export const layer = (evaluate: LazyArg<MetricReader>) =>
+export const layer = (evaluate: LazyArg<MetricReader | Arr.NonEmptyReadonlyArray<MetricReader>>) =>
   Layer.scopedDiscard(Effect.flatMap(
     makeProducer,
     (producer) => registerProducer(producer, evaluate)

packages/opentelemetry/test/Tracer.test.ts

@@ -11,7 +11,7 @@ const TracingLive = NodeSdk.layer(Effect.sync(() => ({
   resource: {
     serviceName: "test"
   },
-  spanProcessor: new SimpleSpanProcessor(new InMemorySpanExporter())
+  spanProcessor: [new SimpleSpanProcessor(new InMemorySpanExporter())]
 })))
 
 // needed to test context propagation