factor out pinging logic into a class and make the cloud installer use it too

Author: trevj

src/cloud/digitalocean/provisioner.ts

@@ -1,6 +1,6 @@
 /// <reference path='../../../../third_party/typings/browser.d.ts' />
 
-import promises = require('../../promises/promises');
+import Pinger = require('../../net/pinger');
 
 declare const freedom: freedom.FreedomInModuleEnv;
 
@@ -110,31 +110,11 @@ class Provisioner {
         }
       }
 
-      // Spin until the server is truly up.
-      // Give it one minute before declaring bankruptcy.
-      console.log('waiting for activity on port 22');
-      return promises.retry(() => {
-        const socket = freedom['core.tcpsocket']();
-
-        const destructor = () => {
-          try {
-            freedom['core.tcpsocket'].close(socket);
-          } catch (e) {
-            console.warn('error destroying socket: ' + e.message);
-          }
-        };
-
-        // TODO: Worth thinking about timeouts here but because this times
-        //       out almost immediately if nothing is listening on the port,
-        //       it works well for our purposes.
-        return socket.connect(this.state_.network['ipv4'], 22).then((unused: any) => {
-          destructor();
-          return this.state_;
-        }, (e: Error) => {
-          destructor();
-          throw e;
-        });
-      }, 60, 1000);
+      // It usually takes several seconds after the API reports success for
+      // SSH on a new droplet to become responsive.
+      return new Pinger(this.state_.network['ipv4'], 22, 60).ping().then(() => {
+        return this.state_;
+      });
     });
   }
 

src/cloud/install/installer.ts

@@ -5,6 +5,7 @@ require('../social/monkey/process');
 import arraybuffers = require('../../arraybuffers/arraybuffers');
 import linefeeder = require('../../net/linefeeder');
 import logging = require('../../logging/logging');
+import Pinger = require('../../net/pinger');
 import queue = require('../../handler/queue');
 
 // https://github.com/borisyankov/DefinitelyTyped/blob/master/ssh2/ssh2-tests.ts
@@ -143,6 +144,12 @@ class CloudInstaller {
           message: 'connection close without invitation URL'
         });
       }).connect(connectConfig);
+    }).then((invite: any) => {
+      // It can take several seconds before the SSH server running
+      // in the new Docker container becomes active.
+      return new Pinger(host, 5000).ping().then(() => {
+        return invite;
+      });
     });
   }
 }

src/cloud/social/provider.ts

@@ -6,7 +6,6 @@ import arraybuffers = require('../../arraybuffers/arraybuffers');
 import crypto = require('crypto');
 import linefeeder = require('../../net/linefeeder');
 import logging = require('../../logging/logging');
-import promises = require('../../promises/promises');
 import queue = require('../../handler/queue');
 
 // https://github.com/borisyankov/DefinitelyTyped/blob/master/ssh2/ssh2-tests.ts
@@ -209,24 +208,15 @@ export class CloudSocialProvider {
       });
     }
 
-    let numAttempts = 0;
-    const connect = () => {
-      log.debug('connection attempt %1...', (++numAttempts));
-      const connection = new Connection(invite, (message: Object) => {
-        this.dispatchEvent_('onMessage', {
-          from: makeClientState(invite.host),
-          // SIGNAL_FROM_SERVER_PEER,
-          message: JSON.stringify(makeVersionedPeerMessage(3002, message))
-        });
-      });
-      return connection.connect().then(() => {
-        return connection;
+    const connection = new Connection(invite, (message: Object) => {
+      this.dispatchEvent_('onMessage', {
+        from: makeClientState(invite.host),
+        // SIGNAL_FROM_SERVER_PEER,
+        message: JSON.stringify(makeVersionedPeerMessage(3002, message))
       });
-    };
-        
-    this.clients_[invite.host] = promises.retryWithExponentialBackoff(connect,
-        MAX_CONNECTION_INTERVAL_MS, INITIAL_CONNECTION_INTERVAL_MS).then(
-        (connection:Connection) => {
+    });
+
+    this.clients_[invite.host] = connection.connect().then(() => {
       log.info('connected to zork on %1', invite.host);
 
       // Fetch the banner, if available, then emit an instance message.

src/net/pinger.ts

@@ -0,0 +1,51 @@
+/// <reference path='../../../third_party/typings/browser.d.ts' />
+
+import logging = require('../logging/logging');
+import promises = require('../promises/promises');
+
+declare const freedom: freedom.FreedomInModuleEnv;
+
+var log: logging.Log = new logging.Log('pinger');
+
+const DEFAULT_TIMEOUT_SECS = 60;
+const DEFAULT_INTERVAL_MS = 1000;
+
+// "Pings" - in an nmap sense - a port until a TCP connection can be established.
+class Pinger {
+  constructor(
+    private host_: string,
+    private port_: number,
+    private timeout_= DEFAULT_TIMEOUT_SECS) { }
+
+  // Resolves once a connection has been established, rejecting if
+  // no connection can be made within the timeout.
+  public ping = (): Promise<void> => {
+    log.debug('pinging %1:%2...', this.host_, this.port_);
+
+    return promises.retry(() => {
+      const socket = freedom['core.tcpsocket']();
+
+      const destructor = () => {
+        try {
+          freedom['core.tcpsocket'].close(socket);
+        } catch (e) {
+          console.warn('error destroying socket: ' + e.message);
+        }
+      };
+
+      // TODO: Worth thinking about timeouts here but because this times
+      //       out almost immediately if nothing is listening on the port,
+      //       it works well for our purposes.
+      return socket.connect(this.host_, this.port_).then((unused: any) => {
+        log.debug('connected to %1:%2', this.host_, this.port_);
+        destructor();
+      }, (e: Error) => {
+        log.debug('connection failed to %1:%2', this.host_, this.port_);
+        destructor();
+        throw e;
+      });
+    }, this.timeout_, DEFAULT_INTERVAL_MS);
+  }
+}
+
+export = Pinger;