[#172124428] Adds option to enable keepalive in fetch client (#628)

pagopa · Apr 2, 2020 · 4ef97f0 · 4ef97f0
1 parent 8c20453
commit 4ef97f0
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Showing 5 changed files with 89 additions and 49 deletions.
diff --git a/src/config.ts b/src/config.ts
@@ -231,42 +231,48 @@ export const API_URL = getRequiredENVVar("API_URL");
 // see https://blog.botframework.com/2018/03/05/fix-snat-exhaustion-node-js-bots/
 const isFetchKeepaliveEnabled = process.env.FETCH_KEEPALIVE_ENABLED === "true";
 
+export const keepAliveAgentOptions = isFetchKeepaliveEnabled
+  ? {
+      freeSocketTimeout:
+        process.env.FETCH_KEEPALIVE_FREE_SOCKET_TIMEOUT === undefined
+          ? undefined
+          : parseInt(process.env.FETCH_KEEPALIVE_FREE_SOCKET_TIMEOUT, 10),
+      keepAlive: true,
+      keepAliveMsecs:
+        process.env.FETCH_KEEPALIVE_KEEPALIVE_MSECS === undefined
+          ? undefined
+          : parseInt(process.env.FETCH_KEEPALIVE_KEEPALIVE_MSECS, 10),
+      maxFreeSockets:
+        process.env.FETCH_KEEPALIVE_MAX_FREE_SOCKETS === undefined
+          ? undefined
+          : parseInt(process.env.FETCH_KEEPALIVE_MAX_FREE_SOCKETS, 10),
+      maxSockets:
+        process.env.FETCH_KEEPALIVE_MAX_SOCKETS === undefined
+          ? undefined
+          : parseInt(process.env.FETCH_KEEPALIVE_MAX_SOCKETS, 10),
+      socketActiveTTL:
+        process.env.FETCH_KEEPALIVE_SOCKET_ACTIVE_TTL === undefined
+          ? undefined
+          : parseInt(process.env.FETCH_KEEPALIVE_SOCKET_ACTIVE_TTL, 10),
+      timeout:
+        process.env.FETCH_KEEPALIVE_TIMEOUT === undefined
+          ? undefined
+          : parseInt(process.env.FETCH_KEEPALIVE_TIMEOUT, 10)
+    }
+  : undefined;
+
 // Returns a fetch instance backed by a keepalive-enabled HTTP agent
-const getKeepaliveFetch: () => typeof fetch = () => {
+const getKeepaliveHttpFetch: (
+  _: agentkeepalive.HttpOptions
+) => typeof fetch = httpOptions => {
   // custom HTTP agent that will reuse sockets
   // see https://github.com/node-modules/agentkeepalive#new-agentoptions
-  const keepaliveAgent = new agentkeepalive.default({
-    freeSocketTimeout:
-      process.env.FETCH_KEEPALIVE_FREE_SOCKET_TIMEOUT === undefined
-        ? undefined
-        : parseInt(process.env.FETCH_KEEPALIVE_FREE_SOCKET_TIMEOUT, 10),
-    keepAlive: true,
-    keepAliveMsecs:
-      process.env.FETCH_KEEPALIVE_KEEPALIVE_MSECS === undefined
-        ? undefined
-        : parseInt(process.env.FETCH_KEEPALIVE_KEEPALIVE_MSECS, 10),
-    maxFreeSockets:
-      process.env.FETCH_KEEPALIVE_MAX_FREE_SOCKETS === undefined
-        ? undefined
-        : parseInt(process.env.FETCH_KEEPALIVE_MAX_FREE_SOCKETS, 10),
-    maxSockets:
-      process.env.FETCH_KEEPALIVE_MAX_SOCKETS === undefined
-        ? undefined
-        : parseInt(process.env.FETCH_KEEPALIVE_MAX_SOCKETS, 10),
-    socketActiveTTL:
-      process.env.FETCH_KEEPALIVE_SOCKET_ACTIVE_TTL === undefined
-        ? undefined
-        : parseInt(process.env.FETCH_KEEPALIVE_SOCKET_ACTIVE_TTL, 10),
-    timeout:
-      process.env.FETCH_KEEPALIVE_TIMEOUT === undefined
-        ? undefined
-        : parseInt(process.env.FETCH_KEEPALIVE_TIMEOUT, 10)
-  });
+  const httpAgent = new agentkeepalive.default(httpOptions);
 
   return (input, init) => {
     const initWithKeepalive = {
       ...(init === undefined ? {} : init),
-      agent: keepaliveAgent
+      agent: httpAgent
     };
     // need to cast to any since node-fetch has a slightly different type
     // signature that DOM's fetch
@@ -276,12 +282,14 @@ const getKeepaliveFetch: () => typeof fetch = () => {
   };
 };
 
-const apiFetch: typeof fetch = isFetchKeepaliveEnabled
-  ? getKeepaliveFetch()
-  : // tslint:disable-next-line: no-any
-    (nodeFetch as any);
+// HTTP-only fetch with keepalive agent
+const httpApiFetch: typeof fetch =
+  keepAliveAgentOptions !== undefined
+    ? getKeepaliveHttpFetch(keepAliveAgentOptions)
+    : // tslint:disable-next-line: no-any
+      (nodeFetch as any);
 
-export const API_CLIENT = new ApiClientFactory(API_KEY, API_URL, apiFetch);
+export const API_CLIENT = new ApiClientFactory(API_KEY, API_URL, httpApiFetch);
 
 // Set default session duration to 30 days
 const DEFAULT_TOKEN_DURATION_IN_SECONDS = 3600 * 24 * 30;
@@ -295,7 +303,8 @@ const pagoPAApiUrlProd = getRequiredENVVar("PAGOPA_API_URL_PROD");
 const pagoPAApiUrlTest = getRequiredENVVar("PAGOPA_API_URL_TEST");
 export const PAGOPA_CLIENT = new PagoPAClientFactory(
   pagoPAApiUrlProd,
-  pagoPAApiUrlTest
+  pagoPAApiUrlTest,
+  httpApiFetch
 );
 
 // Azure Notification Hub credentials.

diff --git a/src/server.ts b/src/server.ts
@@ -2,6 +2,7 @@
  * Main entry point for the Digital Citizenship proxy.
  */
 
+import * as agentkeepalive from "agentkeepalive";
 import * as appInsights from "applicationinsights";
 import { fromNullable } from "fp-ts/lib/Option";
 import * as http from "http";
@@ -14,6 +15,7 @@ import {
   API_BASE_PATH,
   AUTHENTICATION_BASE_PATH,
   ENV,
+  keepAliveAgentOptions,
   PAGOPA_BASE_PATH,
   SAML_CERT,
   SAML_KEY,
@@ -50,7 +52,14 @@ let server: http.Server | https.Server;
  */
 const maybeAppInsightsClient = fromNullable(
   process.env.APPINSIGHTS_INSTRUMENTATIONKEY
-).map(initAppInsights);
+).map(k =>
+  keepAliveAgentOptions !== undefined
+    ? initAppInsights(k)
+    : initAppInsights(k, {
+        httpAgent: new agentkeepalive.default(keepAliveAgentOptions),
+        httpsAgent: new agentkeepalive.HttpsAgent(keepAliveAgentOptions)
+      })
+);
 
 newApp(
   ENV,

diff --git a/src/services/apiClientFactory.ts b/src/services/apiClientFactory.ts
@@ -12,12 +12,12 @@ export default class ApiClientFactory implements IApiClientFactoryInterface {
   private apiClient!: ReturnType<APIClient>;
 
   constructor(
-    private readonly apiKey: string,
-    private readonly apiUrl: string,
+    apiKey: string,
+    apiUrl: string,
     // tslint:disable-next-line: no-any
-    private readonly fetchApi: typeof fetch = nodeFetch as any
+    fetchApi: typeof fetch = nodeFetch as any
   ) {
-    this.apiClient = APIClient(this.apiUrl, this.apiKey, this.fetchApi);
+    this.apiClient = APIClient(apiUrl, apiKey, fetchApi);
   }
 
   /**

diff --git a/src/services/pagoPAClientFactory.ts b/src/services/pagoPAClientFactory.ts
@@ -2,28 +2,37 @@
  * This service builds API clients.
  */
 
+import nodeFetch from "node-fetch";
+
 import {
   IPagoPAClientFactoryInterface,
   PagoPAEnvironment
 } from "./IPagoPAClientFactory";
 
 import { PagoPAClient } from "../clients/pagopa";
 
+// TODO: this class is actually useless as PagoPAClient is immutable, it can be removed
 export default class PagoPAClientFactory
   implements IPagoPAClientFactoryInterface {
+  private prodApiClient!: ReturnType<PagoPAClient>;
+  private testApiClient!: ReturnType<PagoPAClient>;
+
   constructor(
-    public readonly pagoPAApiUrlProd: string,
-    public readonly pagoPAApiUrlTest: string
-  ) {}
+    pagoPAApiUrlProd: string,
+    pagoPAApiUrlTest: string,
+    // tslint:disable-next-line:no-any
+    fetchApi: typeof fetch = (nodeFetch as any) as typeof fetch
+  ) {
+    this.prodApiClient = PagoPAClient(pagoPAApiUrlProd, fetchApi);
+    this.testApiClient = PagoPAClient(pagoPAApiUrlTest, fetchApi);
+  }
 
   /**
    * {@inheritDoc}
    */
   public getClient(environment: PagoPAEnvironment): ReturnType<PagoPAClient> {
-    return PagoPAClient(
-      environment === PagoPAEnvironment.TEST
-        ? this.pagoPAApiUrlTest
-        : this.pagoPAApiUrlProd
-    );
+    return environment === PagoPAEnvironment.TEST
+      ? this.testApiClient
+      : this.prodApiClient;
   }
 }
diff --git a/src/utils/appinsights.ts b/src/utils/appinsights.ts
@@ -26,7 +26,10 @@ interface IInsightsRequestData {
  * - Realtime API metrics
  */
 export function initAppInsights(
-  instrumentationKey: string
+  instrumentationKey: string,
+  config: Partial<
+    Pick<appInsights.TelemetryClient["config"], "httpAgent" | "httpsAgent">
+  > = {}
 ): appInsights.TelemetryClient {
   appInsights
     .setup(instrumentationKey)
@@ -54,6 +57,16 @@ export function initAppInsights(
     appInsights.defaultClient.context.keys.cloudRole
   ] = getValueFromPackageJson("name");
 
+  if (config.httpAgent !== undefined) {
+    // tslint:disable-next-line: no-object-mutation
+    appInsights.defaultClient.config.httpAgent = config.httpAgent;
+  }
+
+  if (config.httpsAgent !== undefined) {
+    // tslint:disable-next-line: no-object-mutation
+    appInsights.defaultClient.config.httpAgent = config.httpsAgent;
+  }
+
   return appInsights.defaultClient;
 }