getsentry · mydea · Oct 3, 2023 · Sep 21, 2023
diff --git a/packages/core/src/tracing/hubextensions.ts b/packages/core/src/tracing/hubextensions.ts
@@ -1,11 +1,11 @@
-import type { ClientOptions, CustomSamplingContext, Options, SamplingContext, TransactionContext } from '@sentry/types';
-import { isNaN, logger } from '@sentry/utils';
+import type { ClientOptions, CustomSamplingContext, TransactionContext } from '@sentry/types';
+import { logger } from '@sentry/utils';
 
 import type { Hub } from '../hub';
 import { getMainCarrier } from '../hub';
-import { hasTracingEnabled } from '../utils/hasTracingEnabled';
 import { registerErrorInstrumentation } from './errors';
 import { IdleTransaction } from './idletransaction';
+import { sampleTransaction } from './sampling';
 import { Transaction } from './transaction';
 
 /** Returns all trace headers that are currently on the top scope. */
@@ -20,126 +20,6 @@ function traceHeaders(this: Hub): { [key: string]: string } {
     : {};
 }
 
-/**
- * Makes a sampling decision for the given transaction and stores it on the transaction.
- *
- * Called every time a transaction is created. Only transactions which emerge with a `sampled` value of `true` will be
- * sent to Sentry.
- *
- * @param transaction: The transaction needing a sampling decision
- * @param options: The current client's options, so we can access `tracesSampleRate` and/or `tracesSampler`
- * @param samplingContext: Default and user-provided data which may be used to help make the decision
- *
- * @returns The given transaction with its `sampled` value set
- */
-function sample<T extends Transaction>(
-  transaction: T,
-  options: Pick<Options, 'tracesSampleRate' | 'tracesSampler' | 'enableTracing'>,
-  samplingContext: SamplingContext,
-): T {
-  // nothing to do if tracing is not enabled
-  if (!hasTracingEnabled(options)) {
-    transaction.sampled = false;
-    return transaction;
-  }
-
-  // if the user has forced a sampling decision by passing a `sampled` value in their transaction context, go with that
-  if (transaction.sampled !== undefined) {
-    transaction.setMetadata({
-      sampleRate: Number(transaction.sampled),
-    });
-    return transaction;
-  }
-
-  // we would have bailed already if neither `tracesSampler` nor `tracesSampleRate` nor `enableTracing` were defined, so one of these should
-  // work; prefer the hook if so
-  let sampleRate;
-  if (typeof options.tracesSampler === 'function') {
-    sampleRate = options.tracesSampler(samplingContext);
-    transaction.setMetadata({
-      sampleRate: Number(sampleRate),
-    });
-  } else if (samplingContext.parentSampled !== undefined) {
-    sampleRate = samplingContext.parentSampled;
-  } else if (typeof options.tracesSampleRate !== 'undefined') {
-    sampleRate = options.tracesSampleRate;
-    transaction.setMetadata({
-      sampleRate: Number(sampleRate),
-    });
-  } else {
-    // When `enableTracing === true`, we use a sample rate of 100%
-    sampleRate = 1;
-    transaction.setMetadata({
-      sampleRate,
-    });
-  }
-
-  // Since this is coming from the user (or from a function provided by the user), who knows what we might get. (The
-  // only valid values are booleans or numbers between 0 and 1.)
-  if (!isValidSampleRate(sampleRate)) {
-    __DEBUG_BUILD__ && logger.warn('[Tracing] Discarding transaction because of invalid sample rate.');
-    transaction.sampled = false;
-    return transaction;
-  }
-
-  // if the function returned 0 (or false), or if `tracesSampleRate` is 0, it's a sign the transaction should be dropped
-  if (!sampleRate) {
-    __DEBUG_BUILD__ &&
-      logger.log(
-        `[Tracing] Discarding transaction because ${
-          typeof options.tracesSampler === 'function'
-            ? 'tracesSampler returned 0 or false'
-            : 'a negative sampling decision was inherited or tracesSampleRate is set to 0'
-        }`,
-      );
-    transaction.sampled = false;
-    return transaction;
-  }
-
-  // Now we roll the dice. Math.random is inclusive of 0, but not of 1, so strict < is safe here. In case sampleRate is
-  // a boolean, the < comparison will cause it to be automatically cast to 1 if it's true and 0 if it's false.
-  transaction.sampled = Math.random() < (sampleRate as number | boolean);
-
-  // if we're not going to keep it, we're done
-  if (!transaction.sampled) {
-    __DEBUG_BUILD__ &&
-      logger.log(
-        `[Tracing] Discarding transaction because it's not included in the random sample (sampling rate = ${Number(
-          sampleRate,
-        )})`,
-      );
-    return transaction;
-  }
-
-  __DEBUG_BUILD__ && logger.log(`[Tracing] starting ${transaction.op} transaction - ${transaction.name}`);
-  return transaction;
-}
-
-/**
- * Checks the given sample rate to make sure it is valid type and value (a boolean, or a number between 0 and 1).
- */
-function isValidSampleRate(rate: unknown): boolean {
-  // we need to check NaN explicitly because it's of type 'number' and therefore wouldn't get caught by this typecheck
-  // eslint-disable-next-line @typescript-eslint/no-explicit-any
-  if (isNaN(rate) || !(typeof rate === 'number' || typeof rate === 'boolean')) {
-    __DEBUG_BUILD__ &&
-      logger.warn(
-        `[Tracing] Given sample rate is invalid. Sample rate must be a boolean or a number between 0 and 1. Got ${JSON.stringify(
-          rate,
-        )} of type ${JSON.stringify(typeof rate)}.`,
-      );
-    return false;
-  }
-
-  // in case sampleRate is a boolean, it will get automatically cast to 1 if it's true and 0 if it's false
-  if (rate < 0 || rate > 1) {
-    __DEBUG_BUILD__ &&
-      logger.warn(`[Tracing] Given sample rate is invalid. Sample rate must be between 0 and 1. Got ${rate}.`);
-    return false;
-  }
-  return true;
-}
-
 /**
  * Creates a new transaction and adds a sampling decision if it doesn't yet have one.
  *
@@ -177,7 +57,7 @@ The transaction will not be sampled. Please use the ${configInstrumenter} instru
   }
 
   let transaction = new Transaction(transactionContext, this);
-  transaction = sample(transaction, options, {
+  transaction = sampleTransaction(transaction, options, {
     parentSampled: transactionContext.parentSampled,
     transactionContext,
     ...customSamplingContext,
@@ -207,7 +87,7 @@ export function startIdleTransaction(
   const options: Partial<ClientOptions> = (client && client.getOptions()) || {};
 
   let transaction = new IdleTransaction(transactionContext, hub, idleTimeout, finalTimeout, heartbeatInterval, onScope);
-  transaction = sample(transaction, options, {
+  transaction = sampleTransaction(transaction, options, {
     parentSampled: transactionContext.parentSampled,
     transactionContext,
     ...customSamplingContext,

diff --git a/packages/core/src/tracing/index.ts b/packages/core/src/tracing/index.ts
@@ -11,3 +11,4 @@ export type { SpanStatusType } from './span';
 export { trace, getActiveSpan, startSpan, startInactiveSpan, startActiveSpan, startSpanManual } from './trace';
 export { getDynamicSamplingContextFromClient } from './dynamicSamplingContext';
 export { setMeasurement } from './measurement';
+export { sampleTransaction } from './sampling';
diff --git a/packages/core/src/tracing/sampling.ts b/packages/core/src/tracing/sampling.ts
@@ -0,0 +1,122 @@
+import type { Options, SamplingContext } from '@sentry/types';
+import { isNaN, logger } from '@sentry/utils';
+
+import { hasTracingEnabled } from '../utils/hasTracingEnabled';
+import type { Transaction } from './transaction';
+
+/**
+ * Makes a sampling decision for the given transaction and stores it on the transaction.
+ *
+ * Called every time a transaction is created. Only transactions which emerge with a `sampled` value of `true` will be
+ * sent to Sentry.
+ *
+ * This method muttes the given `transaction` and will set the `sampled` value on it.
+ * It returns the same transaction, for convenience.
+ */
+export function sampleTransaction<T extends Transaction>(
+  transaction: T,
+  options: Pick<Options, 'tracesSampleRate' | 'tracesSampler' | 'enableTracing'>,
+  samplingContext: SamplingContext,
+): T {
+  // nothing to do if tracing is not enabled
+  if (!hasTracingEnabled(options)) {
+    transaction.sampled = false;
+    return transaction;
+  }
+
+  // if the user has forced a sampling decision by passing a `sampled` value in their transaction context, go with that
+  if (transaction.sampled !== undefined) {
+    transaction.setMetadata({
+      sampleRate: Number(transaction.sampled),
+    });
+    return transaction;
+  }
+
+  // we would have bailed already if neither `tracesSampler` nor `tracesSampleRate` nor `enableTracing` were defined, so one of these should
+  // work; prefer the hook if so
+  let sampleRate;
+  if (typeof options.tracesSampler === 'function') {
+    sampleRate = options.tracesSampler(samplingContext);
+    transaction.setMetadata({
+      sampleRate: Number(sampleRate),
+    });
+  } else if (samplingContext.parentSampled !== undefined) {
+    sampleRate = samplingContext.parentSampled;
+  } else if (typeof options.tracesSampleRate !== 'undefined') {
+    sampleRate = options.tracesSampleRate;
+    transaction.setMetadata({
+      sampleRate: Number(sampleRate),
+    });
+  } else {
+    // When `enableTracing === true`, we use a sample rate of 100%
+    sampleRate = 1;
+    transaction.setMetadata({
+      sampleRate,
+    });
+  }
+
+  // Since this is coming from the user (or from a function provided by the user), who knows what we might get. (The
+  // only valid values are booleans or numbers between 0 and 1.)
+  if (!isValidSampleRate(sampleRate)) {
+    __DEBUG_BUILD__ && logger.warn('[Tracing] Discarding transaction because of invalid sample rate.');
+    transaction.sampled = false;
+    return transaction;
+  }
+
+  // if the function returned 0 (or false), or if `tracesSampleRate` is 0, it's a sign the transaction should be dropped
+  if (!sampleRate) {
+    __DEBUG_BUILD__ &&
+      logger.log(
+        `[Tracing] Discarding transaction because ${
+          typeof options.tracesSampler === 'function'
+            ? 'tracesSampler returned 0 or false'
+            : 'a negative sampling decision was inherited or tracesSampleRate is set to 0'
+        }`,
+      );
+    transaction.sampled = false;
+    return transaction;
+  }
+
+  // Now we roll the dice. Math.random is inclusive of 0, but not of 1, so strict < is safe here. In case sampleRate is
+  // a boolean, the < comparison will cause it to be automatically cast to 1 if it's true and 0 if it's false.
+  transaction.sampled = Math.random() < (sampleRate as number | boolean);
+
+  // if we're not going to keep it, we're done
+  if (!transaction.sampled) {
+    __DEBUG_BUILD__ &&
+      logger.log(
+        `[Tracing] Discarding transaction because it's not included in the random sample (sampling rate = ${Number(
+          sampleRate,
+        )})`,
+      );
+    return transaction;
+  }
+
+  __DEBUG_BUILD__ && logger.log(`[Tracing] starting ${transaction.op} transaction - ${transaction.name}`);
+  return transaction;
+}
+
+/**
+ * Checks the given sample rate to make sure it is valid type and value (a boolean, or a number between 0 and 1).
+ */
+function isValidSampleRate(rate: unknown): boolean {
+  // we need to check NaN explicitly because it's of type 'number' and therefore wouldn't get caught by this typecheck
+  // eslint-disable-next-line @typescript-eslint/no-explicit-any
+  if (isNaN(rate) || !(typeof rate === 'number' || typeof rate === 'boolean')) {
+    __DEBUG_BUILD__ &&
+      logger.warn(
+        `[Tracing] Given sample rate is invalid. Sample rate must be a boolean or a number between 0 and 1. Got ${JSON.stringify(
+          rate,
+        )} of type ${JSON.stringify(typeof rate)}.`,
+      );
+    return false;
+  }
+
+  // in case sampleRate is a boolean, it will get automatically cast to 1 if it's true and 0 if it's false
+  if (rate < 0 || rate > 1) {
+    __DEBUG_BUILD__ &&
+      logger.warn(`[Tracing] Given sample rate is invalid. Sample rate must be between 0 and 1. Got ${rate}.`);
+    return false;
+  }
+  return true;
+}