fix(redis): improved data capturing for legacy mode

packages/collector/test/tracing/databases/redis/app.js

@@ -291,6 +291,18 @@ app.post('/two-different-target-hosts', async (req, res) => {
   }
 });
 
+app.get('/legacy-mode', async (req, res) => {
+  // legacy mode is redis v4 with callback style
+  connection.get('xxxx', (err, result) => {
+    if (err) {
+      log('Get with key xxxx failed', err);
+      res.sendStatus(500);
+    } else {
+      res.send(result);
+    }
+  });
+});
+
 app.listen(port, () => {
   log(`Listening on port: ${port}`);
 });

packages/collector/test/tracing/databases/redis/connect-via/default.js

@@ -5,17 +5,18 @@
 'use strict';
 
 module.exports = async function (redis, log) {
-  const client = redis.createClient({ url: `redis://${process.env.REDIS}` });
-  const client2 = redis.createClient({ url: `redis://${process.env.REDIS_ALTERNATIVE}` });
+  const legacyMode = process.env.REDIS_LEGACY_MODE === 'true';
+  const client = redis.createClient({ url: `redis://${process.env.REDIS}`, legacyMode });
+  const client2 = redis.createClient({ url: `redis://${process.env.REDIS_ALTERNATIVE}`, legacyMode });
   [client, client2].forEach(c => {
     c.on('error', err => log('Redis Client Error', err));
   });
 
-  log('Connecting to client 1');
+  log(`Connecting to client 1 (legacyMode: ${legacyMode})`);
   await client.connect();
   log(`Connected to client 1 (${process.env.REDIS}).`);
 
-  log('Connecting to client 2');
+  log(`Connecting to client 2 (legacyMode: ${legacyMode})`);
   await client2.connect();
   log(`Connected to client 2 (${process.env.REDIS_ALTERNATIVE}).`);
 

packages/collector/test/tracing/databases/redis/default_test.js

@@ -8,4 +8,7 @@ const setupType = 'default';
 
 describe(`tracing/redis/${setupType}`, function () {
   require('./test_definition').call(this, setupType);
+
+  // legacy mode
+  require('./test_definition').call(this, setupType, true);
 });

packages/collector/test/tracing/databases/redis/test_definition.js

@@ -49,7 +49,7 @@ const versionsSinceV5 = ['latest', 'v5.8.3'];
  *        node bin/start-test-containers.js --redis --redis-slave --redis-sentinel
  */
 
-module.exports = function (setupType) {
+module.exports = function (setupType, legacyMode = false) {
   const allVersions = ['latest', 'v5.8.3', 'v4', 'v3'];
 
   let versionsToRun;
@@ -78,7 +78,7 @@ module.exports = function (setupType) {
         }
 
         // The allowRootExitSpanApp is compatable with Redis v4 and v5 (latest).
-        if (redisVersion !== legacyVersion) {
+        if (redisVersion !== legacyVersion && legacyMode === false) {
           mochaSuiteFn('When allowRootExitSpan: true is set', function () {
             globalAgent.setUpCleanUpHooks();
             let controls;
@@ -126,7 +126,7 @@ module.exports = function (setupType) {
           // In v5, Redis moved "Isolation Pool" into RedisClientPool.
           // see: https://github.com/redis/node-redis/blob/master/docs/pool.md
           // Only for this test the connection is established via the pool.
-          if (versionsSinceV5.includes(redisVersion) && setupType === 'default') {
+          if (versionsSinceV5.includes(redisVersion) && setupType === 'default' && legacyMode === false) {
             mochaSuiteFn('When connected via clientpool', function () {
               globalAgent.setUpCleanUpHooks();
               let controls;
@@ -174,7 +174,8 @@ module.exports = function (setupType) {
               env: {
                 REDIS_VERSION: redisVersion,
                 REDIS_PKG: redisPkg,
-                REDIS_SETUP_TYPE: setupType
+                REDIS_SETUP_TYPE: setupType,
+                REDIS_LEGACY_MODE: legacyMode
               }
             });
 
@@ -200,6 +201,34 @@ module.exports = function (setupType) {
             await controls.clearIpcMessages();
           });
 
+          if (redisVersion === 'v4' && legacyMode === true) {
+            it('must trace legacy mode', async () => {
+              await controls.sendRequest({
+                method: 'GET',
+                path: '/legacy-mode'
+              });
+
+              return retry(() =>
+                agentControls.getSpans().then(spans => {
+                  expect(spans.length).to.be.eql(2);
+
+                  expectAtLeastOneMatching(spans, [
+                    span => expect(span.n).to.equal('redis'),
+                    span => expect(span.k).to.equal(constants.EXIT),
+                    span => expect(span.f.e).to.equal(String(controls.getPid())),
+                    span => expect(span.f.h).to.equal('agent-stub-uuid'),
+                    span => expect(span.async).to.not.exist,
+                    span => expect(span.error).to.not.exist,
+                    span => expect(span.ec).to.equal(0),
+                    span => expect(span.d).to.be.greaterThan(1)
+                  ]);
+                })
+              );
+            });
+
+            return;
+          }
+
           it('must trace set/get calls', () =>
             controls
               .sendRequest({

packages/core/src/tracing/instrumentation/databases/redis.js

@@ -182,7 +182,10 @@ function instrument(redis) {
           addressUrl = 'localhost:6379';
         }
 
-        shimAllCommands(redisClient, addressUrl, false, redisCommandList);
+        // legacyMode is a Redis v4 option used to maintain backward-compatible command behavior
+        const isLegacyMode = redisClient.options?.legacyMode === true;
+        const cbStyle = !!isLegacyMode;
+        shimAllCommands(redisClient, addressUrl, cbStyle, redisCommandList);
 
         if (redisClient.multi) {
           shimmer.wrap(redisClient, 'multi', wrapMulti(addressUrl, false));
@@ -357,7 +360,7 @@ function instrumentCommand(original, command, address, cbStyle) {
               return error;
             });
         } else {
-          // No promise returned, call onResult immediately to close the span
+          // UNKNOWN CASE
           onResult();
         }
         return promise;