fix: NODE_ENV envvar for 'environment' was broken in v4.2.0 (#3815)

Fixes: #3807

Author: trentm

Diff for: CHANGELOG.asciidoc

@@ -45,6 +45,10 @@ See the <<upgrade-to-v4>> guide.
 [float]
 ===== Bug fixes
 
+* Fix bug where `NODE_ENV` environment value was not used as a default for
+  the <<environment>> config setting. The bug was introduced in v4.2.0.
+  ({issues}3807[#3807])
+
 * Improve Fastify instrumentation to no longer cause the https://fastify.dev/docs/latest/Reference/Warnings/#FSTDEP017[`FSTDEP017`]
   and https://fastify.dev/docs/latest/Reference/Warnings/#FSTDEP018[`FSTDEP018`]
   deprecation warnings. ({pull}3814[#3814])

Diff for: lib/apm-client/http-apm-client/README.md

@@ -56,7 +56,7 @@ See also the "Cloud & Extra Metadata" section below.
   specific framework, use this config option to log its version
 - `configuredHostname` - A user-configured hostname, if any, e.g. from the `ELASTIC_APM_HOSTNAME` envvar.
   See <https://github.com/elastic/apm/blob/main/specs/agents/metadata.md#hostname>.
-- `environment` - Environment name (default: `process.env.NODE_ENV || 'development'`)
+- `environment` - Environment name (e.g. 'development', 'production')
 - `containerId` - Docker container id, if not given will be parsed from `/proc/self/cgroup`
 - `kubernetesNodeName` - Kubernetes node name
 - `kubernetesNamespace` - Kubernetes namespace

Diff for: lib/apm-client/http-apm-client/index.js

@@ -252,8 +252,6 @@ Client.prototype.config = function (opts) {
   if (!this._conf.serverTimeout && this._conf.serverTimeout !== 0)
     this._conf.serverTimeout = 15000;
   if (!this._conf.serverUrl) this._conf.serverUrl = 'http://127.0.0.1:8200';
-  if (!this._conf.environment)
-    this._conf.environment = process.env.NODE_ENV || 'development';
   if (!this._conf.truncateKeywordsAt) this._conf.truncateKeywordsAt = 1024;
   if (!this._conf.truncateStringsAt) this._conf.truncateStringsAt = 1024;
   if (!this._conf.truncateCustomKeysAt) this._conf.truncateCustomKeysAt = 1024;

Diff for: lib/config/schema.js

@@ -188,7 +188,7 @@ const CONFIG_SCHEMA = [
   {
     name: 'environment',
     configType: 'string',
-    defaultValue: 'development',
+    defaultValue: process.env.NODE_ENV || 'development',
     envVar: 'ELASTIC_APM_ENVIRONMENT',
   },
   {

Diff for: test/apm-client/http-apm-client/lib/utils.js

@@ -230,6 +230,7 @@ function validOpts(opts) {
       agentVersion: 'my-agent-version',
       serviceName: 'my-service-name',
       userAgent: 'my-user-agent',
+      environment: 'development',
     },
     opts,
   );

Diff for: test/config/config.test.js

@@ -395,6 +395,24 @@ const testFixtures = [
       );
     },
   },
+  {
+    name: 'use agent - NODE_ENV envvar sets "environment"',
+    script: 'fixtures/use-agent.js',
+    cwd: __dirname,
+    noConvenienceConfig: true,
+    env: {
+      NODE_ENV: 'this-is-from-node-env',
+      TEST_APM_START_OPTIONS: JSON.stringify({
+        configFile: 'fixtures/use-agent-config.js',
+      }),
+    },
+    checkScriptResult: (t, err, stdout) => {
+      t.error(err, `use-agent.js script succeeded: err=${err}`);
+      const useAgentLogs = getUseAgentLogs(stdout);
+      const resolvedConfig = JSON.parse(useAgentLogs[2]);
+      t.equal(resolvedConfig.environment, 'this-is-from-node-env');
+    },
+  },
   {
     name: 'use agent - should support key/value pairs formats (string & object)',
     script: 'fixtures/use-agent.js',