avoid flaky large blob downloads by working around nodejs/node#3055 (avoid 'agent:false')

Author: trentm

CHANGES.md

@@ -1,8 +1,10 @@
 # node-docker-registry-client Changelog
 
-## 1.4.2 (not yet released)
+## 2.0.0 (not yet released)
 
-(nothing yet)
+- Fix reliability issues with v2 download of large layer files.
+  My understanding is that this was due to <https://github.com/nodejs/node/issues/3055>.
+  This module is now avoiding `agent: false`, at least for the blob downloads.
 
 
 ## 1.4.1
@@ -39,7 +41,7 @@
             //...
         });
 
-  On side-effect of this change is the underlying HTTP connections no longer
+  One side-effect of this change is the underlying HTTP connections no longer
   set `agent: false` to avoid Node's default HTTP agent. This means that if you
   are **not** using a proxy, you will now get keep-alive, which means a
   persistent connection that could hold your node script/app from exiting. All

lib/registry-client-v2.js

@@ -586,6 +586,8 @@ function RegistryClientV2(opts) {
         this._url = common.urlFromIndex(this.repo.index);
     }
 
+    this._clientsToClose = [];
+
     Object.defineProperty(this, '_api', {
         get: function () {
             if (self.__api === undefined) {
@@ -596,13 +598,28 @@ function RegistryClientV2(opts) {
                     rejectUnauthorized: !this.insecure,
                     userAgent: self.userAgent
                 });
+                self._clientsToClose.push(self.__api);
             }
             return this.__api;
         }
     });
 }
 
 
+RegistryClientV2.prototype.version = 2;
+
+
+RegistryClientV2.prototype.close = function close() {
+    for (var i = 0; i < this._clientsToClose.length; i++) {
+        var client = this._clientsToClose[i];
+        this.log.trace({host: client.url && client.url.host},
+            'close http client');
+        client.close();
+    }
+    this._clientsToClose = [];
+};
+
+
 /**
  * Get a registry session token from docker.io.
  *
@@ -714,18 +731,6 @@ RegistryClientV2.prototype._login = function _login(cb) {
     });
 };
 
-RegistryClientV2.prototype.version = 2;
-
-
-RegistryClientV2.prototype.close = function close() {
-    if (this.__api) {
-        this.__api.close();
-    }
-    if (this.__rawApi) {
-        this.__rawApi.close();
-    }
-};
-
 
 //RegistryClientV2.prototype._saveCookies = function _saveCookies(url, res) {
 //    var header = res.headers['set-cookie'];
@@ -947,10 +952,12 @@ RegistryClientV2.prototype._headOrGetBlob = function _headOrGetBlob(opts, cb) {
                 var client = restify.createHttpClient({
                     url: reqOpts.url,
                     log: self.log,
-                    agent: false,
+                    // XXX common opts: agent, proxy
                     rejectUnauthorized: !self.insecure,
                     userAgent: self.userAgent
                 });
+                self._clientsToClose.push(client);
+
                 client[opts.method](reqOpts, function _onConn(connErr, req) {
                     if (connErr) {
                         next(connErr);