feat(tracing): Add enableTracing option

package.json

@@ -25,6 +25,7 @@
     "lint:eslint": "lerna run lint:eslint",
     "postpublish": "lerna run --stream --concurrency 1 postpublish",
     "test": "lerna run --ignore @sentry-internal/* test",
+    "test:unit": "lerna run --ignore @sentry-internal/* test:unit",
     "test-ci-browser": "lerna run test --ignore \"@sentry/{node,opentelemetry-node,serverless,nextjs,remix,gatsby}\" --ignore @sentry-internal/*",
     "test-ci-node": "ts-node ./scripts/node-unit-tests.ts",
     "test:update-snapshots": "lerna run test:update-snapshots"

packages/tracing/package.json

@@ -45,6 +45,7 @@
     "lint": "run-s lint:prettier lint:eslint",
     "lint:eslint": "eslint . --format stylish",
     "lint:prettier": "prettier --check \"{src,test,scripts}/**/**.ts\"",
+    "test:unit": "jest",
     "test": "jest",
     "test:watch": "jest --watch"
   },

packages/tracing/src/hubextensions.ts

@@ -44,7 +44,7 @@ function traceHeaders(this: Hub): { [key: string]: string } {
  */
 function sample<T extends Transaction>(
   transaction: T,
-  options: Pick<Options, 'tracesSampleRate' | 'tracesSampler'>,
+  options: Pick<Options, 'tracesSampleRate' | 'tracesSampler' | 'enableTracing'>,
   samplingContext: SamplingContext,
 ): T {
   // nothing to do if tracing is not enabled
@@ -61,7 +61,7 @@ function sample<T extends Transaction>(
     return transaction;
   }
 
-  // we would have bailed already if neither `tracesSampler` nor `tracesSampleRate` were defined, so one of these should
+  // 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') {
@@ -71,11 +71,17 @@ function sample<T extends Transaction>(
     });
   } else if (samplingContext.parentSampled !== undefined) {
     sampleRate = samplingContext.parentSampled;
-  } else {
+  } 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

packages/tracing/src/utils.ts

@@ -22,11 +22,11 @@ export { TRACEPARENT_REGEXP, extractTraceparentData } from '@sentry/utils';
  * Tracing is enabled when at least one of `tracesSampleRate` and `tracesSampler` is defined in the SDK config.
  */
 export function hasTracingEnabled(
-  maybeOptions?: Pick<Options, 'tracesSampleRate' | 'tracesSampler'> | undefined,
+  maybeOptions?: Pick<Options, 'tracesSampleRate' | 'tracesSampler' | 'enableTracing'> | undefined,
 ): boolean {
   const client = getCurrentHub().getClient();
   const options = maybeOptions || (client && client.getOptions());
-  return !!options && ('tracesSampleRate' in options || 'tracesSampler' in options);
+  return !!options && (options.enableTracing || 'tracesSampleRate' in options || 'tracesSampler' in options);
 }
 
 /** Grabs active transaction off scope, if any */

packages/tracing/test/hub.test.ts

@@ -189,6 +189,57 @@ describe('Hub', () => {
         expect(transaction.sampled).toBe(true);
       });
 
+      it('should set sampled = true if enableTracing is true', () => {
+        const options = getDefaultBrowserClientOptions({ enableTracing: true });
+        const hub = new Hub(new BrowserClient(options));
+        makeMain(hub);
+        const transaction = hub.startTransaction({ name: 'dogpark' });
+
+        expect(transaction.sampled).toBe(true);
+      });
+
+      it('should set sampled = false if enableTracing is true & tracesSampleRate is 0', () => {
+        const options = getDefaultBrowserClientOptions({ enableTracing: true, tracesSampleRate: 0 });
+        const hub = new Hub(new BrowserClient(options));
+        makeMain(hub);
+        const transaction = hub.startTransaction({ name: 'dogpark' });
+
+        expect(transaction.sampled).toBe(false);
+      });
+
+      it('should set sampled = false if enableTracing is false & tracesSampleRate is 0', () => {
+        const options = getDefaultBrowserClientOptions({ enableTracing: false, tracesSampleRate: 0 });
+        const hub = new Hub(new BrowserClient(options));
+        makeMain(hub);
+        const transaction = hub.startTransaction({ name: 'dogpark' });
+
+        expect(transaction.sampled).toBe(false);
+      });
+
+      it('should prefer tracesSampler returning false to enableTracing', () => {
+        // make the two options do opposite things to prove precedence
+        const tracesSampler = jest.fn().mockReturnValue(false);
+        const options = getDefaultBrowserClientOptions({ enableTracing: true, tracesSampler });
+        const hub = new Hub(new BrowserClient(options));
+        makeMain(hub);
+        const transaction = hub.startTransaction({ name: 'dogpark' });
+
+        expect(tracesSampler).toHaveBeenCalled();
+        expect(transaction.sampled).toBe(false);
+      });
+
+      it('should prefer tracesSampler returning true to enableTracing', () => {
+        // make the two options do opposite things to prove precedence
+        const tracesSampler = jest.fn().mockReturnValue(true);
+        const options = getDefaultBrowserClientOptions({ enableTracing: false, tracesSampler });
+        const hub = new Hub(new BrowserClient(options));
+        makeMain(hub);
+        const transaction = hub.startTransaction({ name: 'dogpark' });
+
+        expect(tracesSampler).toHaveBeenCalled();
+        expect(transaction.sampled).toBe(true);
+      });
+
       it('should not try to override explicitly set positive sampling decision', () => {
         // so that the decision otherwise would be false
         const tracesSampler = jest.fn().mockReturnValue(0);

packages/tracing/test/utils.test.ts

@@ -5,10 +5,24 @@ describe('hasTracingEnabled', () => {
   const tracesSampleRate = 1;
   it.each([
     ['No options', undefined, false],
-    ['No tracesSampler or tracesSampleRate', {}, false],
+    ['No tracesSampler or tracesSampleRate or enableTracing', {}, false],
     ['With tracesSampler', { tracesSampler }, true],
     ['With tracesSampleRate', { tracesSampleRate }, true],
+    ['With enableTracing=true', { enableTracing: true }, true],
+    ['With enableTracing=false', { enableTracing: false }, false],
+    ['With tracesSampler && enableTracing=false', { tracesSampler, enableTracing: false }, true],
+    ['With tracesSampleRate && enableTracing=false', { tracesSampler, enableTracing: false }, true],
     ['With tracesSampler and tracesSampleRate', { tracesSampler, tracesSampleRate }, true],
+    [
+      'With tracesSampler and tracesSampleRate and enableTracing=true',
+      { tracesSampler, tracesSampleRate, enableTracing: true },
+      true,
+    ],
+    [
+      'With tracesSampler and tracesSampleRate and enableTracing=false',
+      { tracesSampler, tracesSampleRate, enableTracing: false },
+      true,
+    ],
   ])(
     '%s',
     (_: string, input: Parameters<typeof hasTracingEnabled>[0], output: ReturnType<typeof hasTracingEnabled>) => {

packages/types/src/options.ts

@@ -96,6 +96,13 @@ export interface ClientOptions<TO extends BaseTransportOptions = BaseTransportOp
    */
   tracesSampleRate?: number;
 
+  /**
+   * If this is enabled, transactions and trace data will be generated and captured.
+   * This will set the `tracesSampleRate` to the recommended default of `1.0`.
+   * Note that `tracesSampleRate` and `tracesSampler` take precedence over this option.
+   */
+  enableTracing?: boolean;
+
   /**
    * Initial data to populate scope.
    */