feat: Azure Function utilization (#3017)

Author: amychisholm03

lib/config/default.js

@@ -492,6 +492,14 @@ defaultConfig.definition = () => ({
       formatter: boolean,
       default: true
     },
+    /**
+     * This flag dictates whether the agent attempts to read environment variables
+     * and invocation context to get info about the Azure Function called.
+     */
+    detect_azurefunction: {
+      formatter: boolean,
+      default: true
+    },
     /**
      * This flag dictates whether the agent attempts to read files
      * to get info about the container the process is running in.

lib/utilization/azurefunction-info.js

@@ -0,0 +1,44 @@
+/*
+ * Copyright 2025 New Relic Corporation. All rights reserved.
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+'use strict'
+
+const logger = require('../logger.js').child({ component: 'azurefunction-info' })
+const NAMES = require('../metrics/names.js')
+let results = null
+
+module.exports = fetchAzureFunctionInfo
+module.exports.clearCache = function clearAzureFunctionCache() {
+  results = null
+}
+
+function fetchAzureFunctionInfo(agent, callback) {
+  if (!agent.config.utilization || !agent.config.utilization.detect_azurefunction) {
+    return setImmediate(callback, null, null)
+  }
+
+  if (results) {
+    return setImmediate(callback, null, results)
+  }
+
+  // Detect if Azure Function.
+  const { REGION_NAME, WEBSITE_OWNER_NAME, WEBSITE_SITE_NAME, WEBSITE_RESOURCE_GROUP } = process.env
+  if (!REGION_NAME || !WEBSITE_OWNER_NAME || !WEBSITE_SITE_NAME) {
+    logger.debug('Azure Function metadata was invalid.')
+    agent.metrics.getOrCreateMetric(NAMES.UTILIZATION.AZURE_ERROR).incrementCallCount()
+    return setImmediate(callback, null, null)
+  }
+
+  // Derive vendor metadata from environment variables.
+  const subscriptionId = WEBSITE_OWNER_NAME.split('+')[0]
+  const resourceGroupName = WEBSITE_RESOURCE_GROUP ?? WEBSITE_OWNER_NAME.split('+').pop().split('-Linux').shift() ?? 'unknown'
+  const azureFunctionAppName = WEBSITE_SITE_NAME
+  results = {
+    'faas.app_name': `/subscriptions/${subscriptionId}/resourceGroups/${resourceGroupName}/providers/Microsoft.Web/sites/${azureFunctionAppName}`,
+    'cloud.region': REGION_NAME
+  }
+
+  callback(null, results)
+}

lib/utilization/index.js

@@ -10,6 +10,7 @@ const logger = require('../logger').child({ component: 'utilization' })
 const VENDOR_METHODS = {
   aws: require('./aws-info'),
   azure: require('./azure-info'),
+  azurefunction: require('./azurefunction-info'),
   docker: require('./docker-info').getVendorInfo,
   ecs: require('./ecs-info'),
   gcp: require('./gcp-info'),

test/integration/utilization/azurefunction-info.test.js

@@ -0,0 +1,88 @@
+/*
+ * Copyright 2025 New Relic Corporation. All rights reserved.
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+'use strict'
+
+const test = require('node:test')
+const assert = require('node:assert')
+const helper = require('#testlib/agent_helper.js')
+const fetchAzureFunctionInfo = require('#agentlib/utilization/azurefunction-info.js')
+
+test.beforeEach((ctx) => {
+  const agent = helper.loadMockedAgent({
+    config: {
+      utilization: {
+        detect_azurefunction: true
+      }
+    }
+  })
+  ctx.nr = { agent }
+})
+
+test.afterEach((ctx) => {
+  helper.unloadAgent(ctx.nr.agent)
+  ctx.nr.agent = null
+  fetchAzureFunctionInfo.clearCache()
+})
+
+test('should return null if detect_azurefunction is disabled', (ctx, end) => {
+  const agent = ctx.nr.agent
+  agent.config.utilization.detect_azurefunction = false
+
+  fetchAzureFunctionInfo(agent, (err, result) => {
+    assert.strictEqual(err, null)
+    assert.strictEqual(result, null)
+    end()
+  })
+})
+
+test('should increment error metric if required environment variables are missing', (ctx, end) => {
+  const agent = ctx.nr.agent
+  const azureErrorMetric = agent.metrics.getOrCreateMetric('Supportability/utilization/azure/error')
+
+  const initialCallCount = azureErrorMetric.callCount
+
+  fetchAzureFunctionInfo(agent, (err, result) => {
+    assert.strictEqual(err, null)
+    assert.strictEqual(result, null)
+    assert.strictEqual(azureErrorMetric.callCount, initialCallCount + 1)
+    end()
+  })
+})
+
+test('should derive metadata from required environment variables', (ctx, end) => {
+  const agent = ctx.nr.agent
+
+  process.env.REGION_NAME = 'Central US'
+  process.env.WEBSITE_OWNER_NAME = '12345+resource-group'
+  process.env.WEBSITE_SITE_NAME = 'my-function-app'
+
+  fetchAzureFunctionInfo(agent, (err, result) => {
+    assert.strictEqual(err, null)
+    assert.deepStrictEqual(result, {
+      'faas.app_name': '/subscriptions/12345/resourceGroups/resource-group/providers/Microsoft.Web/sites/my-function-app',
+      'cloud.region': 'Central US'
+    })
+    end()
+  })
+})
+
+test('should derive metadata from required and optional environment variables', (ctx, end) => {
+  const agent = ctx.nr.agent
+
+  process.env.REGION_NAME = 'Central US'
+  process.env.WEBSITE_RESOURCE_GROUP = 'resource-group-actual'
+  process.env.WEBSITE_OWNER_NAME = '12345+resource-group'
+  process.env.WEBSITE_SITE_NAME = 'my-function-app'
+
+  fetchAzureFunctionInfo(agent, (err, result) => {
+    assert.strictEqual(err, null)
+    assert.deepStrictEqual(result, {
+      'faas.app_name': '/subscriptions/12345/resourceGroups/resource-group-actual/providers/Microsoft.Web/sites/my-function-app',
+      'cloud.region': 'Central US'
+    })
+    end()
+  })
+})

test/unit/utilization/main.test.js

@@ -16,6 +16,7 @@ test('getVendors', async function (t) {
     ctx.nr.agent.config.utilization = {
       detect_aws: true,
       detect_azure: true,
+      detect_azurefunction: true,
       detect_gcp: true,
       detect_docker: true,
       detect_kubernetes: true,
@@ -31,6 +32,7 @@ test('getVendors', async function (t) {
     const { agent } = ctx.nr
     let awsCalled = false
     let azureCalled = false
+    let azureFunctionCalled = false
     let gcpCalled = false
     let dockerCalled = false
     let ecsCalled = false
@@ -46,6 +48,10 @@ test('getVendors', async function (t) {
         azureCalled = true
         cb()
       },
+      './azurefunction-info': function (agentArg, cb) {
+        azureFunctionCalled = true
+        cb()
+      },
       './gcp-info': function (agentArg, cb) {
         gcpCalled = true
         cb()
@@ -74,6 +80,7 @@ test('getVendors', async function (t) {
       assert.ifError(err)
       assert.ok(awsCalled)
       assert.ok(azureCalled)
+      assert.ok(azureFunctionCalled)
       assert.ok(gcpCalled)
       assert.ok(dockerCalled)
       assert.ok(ecsCalled)