chore(otel-node): add env var parser

packages/opentelemetry-node/lib/detectors.js

@@ -103,9 +103,7 @@ function resolveDetectors(detectors) {
         return detectors;
     }
 
-    const detectorsFromEnv = getEnvVar('OTEL_NODE_RESOURCE_DETECTORS') || 'all';
-    let detectorKeys = detectorsFromEnv.split(',').map((s) => s.trim());
-
+    let detectorKeys = getEnvVar('OTEL_NODE_RESOURCE_DETECTORS');
     if (detectorKeys.some((k) => k === 'all')) {
         detectorKeys = Object.keys(defaultDetectors);
     } else if (detectorKeys.some((k) => k === 'none')) {

packages/opentelemetry-node/lib/elastic-node-sdk.js

@@ -28,7 +28,11 @@ const {BatchLogRecordProcessor} = require('@opentelemetry/sdk-logs');
 
 const {log, registerOTelDiagLogger} = require('./logging');
 const {resolveDetectors} = require('./detectors');
-const {setupEnvironment, restoreEnvironment} = require('./environment');
+const {
+    setupEnvironment,
+    restoreEnvironment,
+    getEnvVar,
+} = require('./environment');
 const {getInstrumentations} = require('./instrumentations');
 const {enableHostMetrics, HOST_METRICS_VIEWS} = require('./metrics/host');
 // @ts-ignore - compiler options do not allow lookp outside `lib` folder
@@ -63,8 +67,7 @@ class ElasticNodeSDK extends NodeSDK {
         // Get logs exporter protocol based on environment.
         const logsExportProtocol =
             process.env.OTEL_EXPORTER_OTLP_LOGS_PROTOCOL ||
-            process.env.OTEL_EXPORTER_OTLP_PROTOCOL ||
-            'http/protobuf';
+            getEnvVar('OTEL_EXPORTER_OTLP_PROTOCOL');
         let logExporterType = exporterPkgNameFromEnvVar[logsExportProtocol];
         if (!logExporterType) {
             log.warn(
@@ -88,15 +91,12 @@ class ElasticNodeSDK extends NodeSDK {
         // TODO what `temporalityPreference`?
 
         // Disable metrics by config
-        const metricsDisabled =
-            process.env.ELASTIC_OTEL_METRICS_DISABLED === 'true';
+        const metricsDisabled = getEnvVar('ELASTIC_OTEL_METRICS_DISABLED');
         if (!metricsDisabled) {
             // Get metrics exporter protocol based on environment.
-
             const metricsExportProtocol =
                 process.env.OTEL_EXPORTER_OTLP_METRICS_PROTOCOL ||
-                process.env.OTEL_EXPORTER_OTLP_PROTOCOL ||
-                'http/protobuf';
+                getEnvVar('OTEL_EXPORTER_OTLP_PROTOCOL');
             let metricExporterType =
                 exporterPkgNameFromEnvVar[metricsExportProtocol];
             if (!metricExporterType) {
@@ -111,12 +111,9 @@ class ElasticNodeSDK extends NodeSDK {
             const {OTLPMetricExporter} = require(
                 `@opentelemetry/exporter-metrics-otlp-${metricExporterType}`
             );
-            // Note: Default values has been taken from the specs
-            // https://opentelemetry.io/docs/specs/otel/configuration/sdk-environment-variables/#periodic-exporting-metricreader
-            const metricsInterval =
-                Number(process.env.OTEL_METRIC_EXPORT_INTERVAL) || 60000;
-            const metricsTimeout =
-                Number(process.env.OTEL_METRIC_EXPORT_TIMEOUT) || 30000;
+
+            const metricsInterval = getEnvVar('OTEL_METRIC_EXPORT_INTERVAL');
+            const metricsTimeout = getEnvVar('OTEL_METRIC_EXPORT_TIMEOUT');
             defaultConfig.metricReader =
                 new metrics.PeriodicExportingMetricReader({
                     exporter: new OTLPMetricExporter(),

packages/opentelemetry-node/lib/environment.js

@@ -17,54 +17,51 @@
  * under the License.
  */
 
-// @ts-ignore - compiler options do not allow lookp outside `lib` folder
-const ELASTIC_SDK_VERSION = require('../package.json').version;
-const OTEL_SDK_VERSION =
-    require('@opentelemetry/sdk-node/package.json').version;
-const USER_AGENT_PREFIX = `elastic-otel-node/${ELASTIC_SDK_VERSION}`;
-const USER_AGENT_HEADER = `${USER_AGENT_PREFIX} OTel-OTLP-Exporter-JavaScript/${OTEL_SDK_VERSION}`;
+const {getEnv} = require('@opentelemetry/core');
 
 /** @type {NodeJS.ProcessEnv} */
 const envToRestore = {};
 
 /**
- * Reads a string in the format `key-1=value,key2=value2` and parses
- * it into an object. This is the format specified for key value pairs
- * for OTEL environment vars. Example:
- * https://opentelemetry.io/docs/concepts/sdk-configuration/otlp-exporter-configuration/#otel_exporter_otlp_headers
- *
- * If the param is not defined or falsy it returns an empty object
- *
+ * Returns an array of strings from the given input. If undefined returns the fallback
+ * value.
  * @param {string | undefined} str
- * @returns {Record<string, string>}
+ * @param {string[]} [fallback=[]]
+ * @returns {string[]}
  */
-function parseKeyValuePairs(str) {
+function parseStringList(str, fallback = []) {
     if (!str) {
-        return {};
+        return fallback;
     }
+    return str.split(',').map((s) => s.trim());
+}
 
-    const pairs = str.split(',');
-
-    return pairs.reduce((record, text) => {
-        const sepIndex = text.indexOf('=');
-        const key = text.substring(0, sepIndex);
-        const val = text.substring(sepIndex + 1);
-
-        record[key] = val;
-        return record;
-    }, {});
+/**
+ * Returns a boolean from te given input
+ * @param {string | undefined} str
+ * @param {boolean} fallback
+ * @returns {boolean}
+ */
+function parseBoolean(str, fallback) {
+    if (!str) {
+        return fallback;
+    }
+    return str.toLowerCase() === 'true';
 }
 
 /**
- * Serializes an object to a string in the format `key-1=value,key2=value2`
- *
- * @param {Record<string, string>} pairs
- * @returns {string}
+ * Returns a boolean from te given input
+ * @param {string | undefined} str
+ * @param {number} fallback
+ * @returns {number}
  */
-function serializeKeyValuePairs(pairs) {
-    return Object.entries(pairs)
-        .map(([key, val]) => `${key}=${val}`)
-        .join(',');
+function parseNumber(str, fallback) {
+    if (!str) {
+        return fallback;
+    }
+
+    const num = Number(str);
+    return isNaN(num) ? fallback : num;
 }
 
 /**
@@ -79,37 +76,6 @@ function setupEnvironment() {
         process.env.OTEL_TRACES_EXPORTER = 'otlp';
     }
 
-    // Work with exporter headers:
-    // - Add our `user-agent` header in headers for traces, matrics & logs
-    // - comply with OTEL_EXPORTER_OTLP_HEADERS spec until the issue is fixed
-    // TODO: should we stash and restore? if so the restoration should be done
-    // after start
-    const userAgentHeader = {'User-Agent': USER_AGENT_HEADER};
-    // TODO: for now we omit our user agent if already defined elsewhere
-    const tracesHeaders = Object.assign(
-        {},
-        userAgentHeader,
-        parseKeyValuePairs(process.env.OTEL_EXPORTER_OTLP_TRACES_HEADERS)
-    );
-    process.env.OTEL_EXPORTER_OTLP_TRACES_HEADERS =
-        serializeKeyValuePairs(tracesHeaders);
-
-    const metricsHeaders = Object.assign(
-        {},
-        userAgentHeader,
-        parseKeyValuePairs(process.env.OTEL_EXPORTER_OTLP_METRICS_HEADERS)
-    );
-    process.env.OTEL_EXPORTER_OTLP_METRICS_HEADERS =
-        serializeKeyValuePairs(metricsHeaders);
-
-    const logsHeaders = Object.assign(
-        {},
-        userAgentHeader,
-        parseKeyValuePairs(process.env.OTEL_EXPORTER_OTLP_LOGS_HEADERS)
-    );
-    process.env.OTEL_EXPORTER_OTLP_LOGS_HEADERS =
-        serializeKeyValuePairs(logsHeaders);
-
     if ('OTEL_LOG_LEVEL' in process.env) {
         envToRestore['OTEL_LOG_LEVEL'] = process.env.OTEL_LOG_LEVEL;
         // Make sure NodeSDK doesn't see this envvar and overwrite our diag
@@ -127,7 +93,7 @@ function setupEnvironment() {
 }
 
 /**
- * Restores any value stashed in the stup process
+ * Restores any value stashed in the setup process
  */
 function restoreEnvironment() {
     Object.keys(envToRestore).forEach((k) => {
@@ -136,12 +102,56 @@ function restoreEnvironment() {
 }
 
 /**
- * Gets the env var value also checking in the vars pending to be restored
- * @param {string} name
- * @returns {string | undefined}
+ * @typedef {import('@opentelemetry/core').ENVIRONMENT} OtelEnv
+ */
+/**
+ * @typedef {Object} EdotEnv
+ * @property {string[]} OTEL_NODE_RESOURCE_DETECTORS
+ * @property {number} OTEL_METRIC_EXPORT_INTERVAL
+ * @property {number} OTEL_METRIC_EXPORT_TIMEOUT
+ * @property {boolean} ELASTIC_OTEL_METRICS_DISABLED
+ */
+const otelEnv = getEnv();
+/** @type {EdotEnv} */
+const edotEnv = {
+    // Missing OTEL_ vars from global spec and nodejs specific spec
+    OTEL_NODE_RESOURCE_DETECTORS: parseStringList(
+        process.env.OTEL_NODE_RESOURCE_DETECTORS,
+        ['all']
+    ),
+    // Note: Default values has been taken from the specs
+    // https://opentelemetry.io/docs/specs/otel/configuration/sdk-environment-variables/#periodic-exporting-metricreader
+    OTEL_METRIC_EXPORT_INTERVAL: parseNumber(
+        process.env.OTEL_METRIC_EXPORT_INTERVAL,
+        60000
+    ),
+    OTEL_METRIC_EXPORT_TIMEOUT: parseNumber(
+        process.env.OTEL_METRIC_EXPORT_TIMEOUT,
+        30000
+    ),
+    // ELASTIC_OTEL_ vars
+    ELASTIC_OTEL_METRICS_DISABLED: parseBoolean(
+        process.env.ELASTIC_OTEL_METRICS_DISABLED,
+        false
+    ),
+};
+
+/**
+ * @template {keyof OtelEnv | keyof EdotEnv} T
+ * Returns the value of the env var already parsed to the proper type. If
+ * the variable is not defined it will return the dafault value based on
+ * the environmment variables spec https://opentelemetry.io/docs/specs/otel/configuration/sdk-environment-variables/
+ * @param {T} name
+ * @returns {T extends keyof OtelEnv ? OtelEnv[T] : EdotEnv[T]}
  */
 function getEnvVar(name) {
-    return process.env[name] || envToRestore[name];
+    if (name in otelEnv) {
+        // @ts-ignore -- T is {keyof OtelEnv} but not sure how to make TS infer that
+        return otelEnv[name];
+    }
+
+    // @ts-ignore -- T is {keyof EdotEnv} but not sure how to make TS infer that
+    return edotEnv[name];
 }
 
 module.exports = {

packages/opentelemetry-node/lib/instrumentations.js

@@ -92,6 +92,7 @@ const {UndiciInstrumentation} = require('@opentelemetry/instrumentation-undici')
 const {WinstonInstrumentation} = require('@opentelemetry/instrumentation-winston');
 
 const {log} = require('./logging');
+const { getEnvVar } = require('./environment');
 
 // Instrumentations attach their Hook (for require-in-the-middle or import-in-the-middle)
 // when the `enable` method is called and this happens inside their constructor
@@ -236,8 +237,7 @@ function getInstrumentations(opts = {}) {
         }
 
         // Skip if metrics are disabled by env var
-        const isMetricsDisabled =
-            process.env.ELASTIC_OTEL_METRICS_DISABLED === 'true';
+        const isMetricsDisabled = getEnvVar('ELASTIC_OTEL_METRICS_DISABLED');
         if (
             isMetricsDisabled &&
             name === '@opentelemetry/instrumentation-runtime-node'

packages/opentelemetry-node/package.json

@@ -64,6 +64,7 @@
   },
   "types": "types/index.d.ts",
   "dependencies": {
+    "@opentelemetry/core": "1.27.0",
     "@opentelemetry/exporter-logs-otlp-grpc": "^0.54.0",
     "@opentelemetry/exporter-logs-otlp-http": "^0.54.0",
     "@opentelemetry/exporter-logs-otlp-proto": "^0.54.0",