test(evp-proxy): use forwarded discovery header

Author: leoromanovsky

packages/dd-trace/src/evp_proxy/discovery.js

@@ -49,8 +49,8 @@ const TRAILING_SLASHES = /\/+$/
  * @param {object} agentInfo - Agent `/info` response
  * @param {object} options - Selection options
  * @param {string[]} options.supportedPaths - Supported paths in preference order
- * @param {string[]} [options.requiredHeaders] - Headers that the proxy must forward to intake. Do not include
- * routing headers that the Agent consumes, such as X-Datadog-EVP-Subdomain.
+ * @param {string[]} [options.requiredHeaders] - Headers that the proxy must forward unchanged to intake. Each
+ * header must appear in `evp_proxy_allowed_headers`. Do not include routing headers that the Agent consumes.
  * @returns {string|undefined} Selected normalized path
  */
 function selectEVPProxyPath (agentInfo, { supportedPaths, requiredHeaders = [] } = {}) {
@@ -103,8 +103,8 @@ function selectEVPProxyPath (agentInfo, { supportedPaths, requiredHeaders = [] }
  * @param {URL} url - Configured Agent URL
  * @param {object} options - Selection options
  * @param {string[]} options.supportedPaths - Supported paths in preference order
- * @param {string[]} [options.requiredHeaders] - Headers that the proxy must forward to intake. Do not include
- * routing headers that the Agent consumes, such as X-Datadog-EVP-Subdomain.
+ * @param {string[]} [options.requiredHeaders] - Headers that the proxy must forward unchanged to intake. Each
+ * header must appear in `evp_proxy_allowed_headers`. Do not include routing headers that the Agent consumes.
  * @param {(error: Error|null, route?: {url: URL, basePath: string}) => void} callback - Result callback
  * @returns {void}
  */

packages/dd-trace/test/evp_proxy/discovery.spec.js

@@ -10,7 +10,7 @@ describe('EVP proxy discovery', () => {
   const url = new URL('http://localhost:8126')
   const options = {
     supportedPaths: ['/evp_proxy/v4', '/evp_proxy/v2'],
-    requiredHeaders: ['X-Datadog-EVP-Subdomain'],
+    requiredHeaders: ['Content-Type'],
   }
 
   let discoverEVPProxy
@@ -35,7 +35,7 @@ describe('EVP proxy discovery', () => {
     it('uses caller preference order and normalizes trailing slashes', () => {
       const path = selectEVPProxyPath({
         endpoints: ['/evp_proxy/v2/', '/evp_proxy/v4/'],
-        evp_proxy_allowed_headers: ['x-datadog-evp-subdomain'],
+        evp_proxy_allowed_headers: ['content-type'],
       }, options)
 
       assert.strictEqual(path, '/evp_proxy/v4')
@@ -64,7 +64,7 @@ describe('EVP proxy discovery', () => {
     it('rejects a malformed allowed-header field', () => {
       const path = selectEVPProxyPath({
         endpoints: ['/evp_proxy/v2'],
-        evp_proxy_allowed_headers: 'X-Datadog-EVP-Subdomain',
+        evp_proxy_allowed_headers: 'Content-Type',
       }, options)
 
       assert.strictEqual(path, undefined)
@@ -73,7 +73,7 @@ describe('EVP proxy discovery', () => {
     it('rejects a missing required header', () => {
       const path = selectEVPProxyPath({
         endpoints: ['/evp_proxy/v2'],
-        evp_proxy_allowed_headers: ['Content-Type'],
+        evp_proxy_allowed_headers: ['Accept-Encoding'],
       }, options)
 
       assert.strictEqual(path, undefined)
@@ -88,7 +88,7 @@ describe('EVP proxy discovery', () => {
     it('fetches information only when discovery is called', (done) => {
       fetchAgentInfo.yields(null, {
         endpoints: ['/evp_proxy/v2'],
-        evp_proxy_allowed_headers: ['X-Datadog-EVP-Subdomain'],
+        evp_proxy_allowed_headers: ['content-type'],
       })
 
       sinon.assert.notCalled(fetchAgentInfo)