Merge pull request #573 from embark-framework/bug_fix/blockchain-kill-causes-error

Handle geth process exit via crash/kill and also via killing `embark blockchain`

lib/cmds/blockchain/blockchain.js

@@ -14,6 +14,7 @@ var Blockchain = function(options) {
   this.client = options.client;
   this.isDev = options.isDev;
   this.onReadyCallback = options.onReadyCallback;
+  this.onExitCallback = options.onExitCallback;
 
   if ((this.blockchainConfig === {} || JSON.stringify(this.blockchainConfig) === '{"enabled":true}') && this.env !== 'development') {
     console.log("===> " + __("warning: running default config on a non-development environment"));
@@ -167,8 +168,24 @@ Blockchain.prototype.run = function() {
       console.log('Geth: ' + data);
     });
     self.child.on('exit', (code) => {
+      let strCode;
       if (code) {
-        console.error('Geth exited with error code ' + code);
+        strCode = ' with error code ' + code;
+      } else {
+        strCode = ' with no error code (manually killed?)';
+      }
+      console.error('Geth exited' + strCode);
+
+      if(self.onExitCallback){
+        self.onExitCallback();
+      }
+    });
+
+    self.child.on('uncaughtException', (err) => {
+      console.error('Uncaught geth exception', err);
+
+      if(self.onExitCallback){
+        self.onExitCallback();
       }
     });
   });
@@ -252,10 +269,10 @@ Blockchain.prototype.initChainAndGetAddress = function(callback) {
   });
 };
 
-var BlockchainClient = function(blockchainConfig, client, env, isDev, onReadyCallback) {
+var BlockchainClient = function(blockchainConfig, client, env, isDev, onReadyCallback, onExitCallback) {
   // TODO add other clients at some point
   if (client === 'geth') {
-    return new Blockchain({blockchainConfig, client: GethCommands, env, isDev, onReadyCallback});
+    return new Blockchain({blockchainConfig, client: GethCommands, env, isDev, onReadyCallback, onExitCallback});
   } else {
     throw new Error('unknown client');
   }

lib/cmds/blockchain/blockchainProcess.js

@@ -21,7 +21,8 @@ class BlockchainProcess extends ProcessWrapper {
       this.client,
       this.env,
       this.isDev,
-      this.blockchainReady.bind(this)
+      this.blockchainReady.bind(this),
+      this.blockchainExit.bind(this)
     );
 
     this.blockchain.run();
@@ -31,6 +32,11 @@ class BlockchainProcess extends ProcessWrapper {
     blockchainProcess.send({result: constants.blockchain.blockchainReady});
   }
 
+  blockchainExit() {
+    // tell our parent process that geth has exited
+    blockchainProcess.send({result: constants.blockchain.blockchainExit});
+  }
+
   kill() {
     this.blockchain.kill();
   }

lib/constants.json

@@ -34,6 +34,7 @@
   },
   "blockchain": {
     "blockchainReady": "blockchainReady",
+    "blockchainExit": "blockchainExit",
     "init": "init",
     "initiated": "initiated",
     "servicePortOnProxy": 10

lib/contracts/blockchain.js

@@ -48,7 +48,7 @@ class Blockchain {
     }
 
     const protocol = (this.contractsConfig.deployment.type === "rpc") ? this.contractsConfig.deployment.protocol : 'ws';
-    let provider;
+    
     this.web3Endpoint = utils.buildUrl(protocol, this.contractsConfig.deployment.host, this.contractsConfig.deployment.port);//`${protocol}://${this.contractsConfig.deployment.host}:${this.contractsConfig.deployment.port}`;
 
     const providerOptions = {
@@ -60,7 +60,7 @@ class Blockchain {
       type: this.contractsConfig.deployment.type,
       web3Endpoint: self.web3Endpoint
     };
-    provider = new Provider(providerOptions);
+    this.provider = new Provider(providerOptions);
 
     async.waterfall([
       function checkNode(next) {
@@ -73,21 +73,35 @@ class Blockchain {
           if (!err) {
             self.isWeb3Ready = true;
             self.events.emit(WEB3_READY);
+            // if the ethereum node goes offline, we need a check to ensure
+            // the provider is also stopped
+            self.events.on('check:wentOffline:Ethereum', () => {
+              self.logger.trace('Ethereum went offline: stopping web3 provider...');
+              self.provider.stop();
+              
+              // once the node goes back online, we can restart the provider
+              self.events.once('check:backOnline:Ethereum', () => {
+                self.logger.trace('Ethereum back online: starting web3 provider...');
+                self.provider.startWeb3Provider(() => {
+                  self.logger.trace('web3 provider restarted after ethereum node came back online');
+                });
+              });
+            });
             return next();
           }
           self.web3StartedInProcess = true;
           self.startBlockchainNode(() => {
             // Need to re-initialize web3 to connect to the new blockchain node
-            provider.stop();
+            self.provider.stop();
             self.initWeb3(cb);
           });
         });
       },
       function startProvider(next) {
-        provider.startWeb3Provider(next);
+        self.provider.startWeb3Provider(next);
       },
       function fundAccountsIfNeeded(next) {
-        provider.fundAccounts(next);
+        self.provider.fundAccounts(next);
       }
     ], (err) => {
       self.registerWeb3Object();
@@ -120,6 +134,10 @@ class Blockchain {
     self.events.once(constants.blockchain.blockchainReady, () => {
       callback();
     });
+    self.events.once(constants.blockchain.blockchainExit, () => {
+      self.provider.stop();
+      callback();
+    });
   }
 
   registerServiceCheck() {

lib/contracts/provider.js

@@ -39,12 +39,16 @@ class Provider {
 
     // network connectivity error
     self.engine.on('error', (err) => {
-      // report connectivity errors
+      // report connectivity errors as trace due to polling
-      self.logger.error(err.stack);
+      self.logger.trace('web3 provider error: ', err);
+      self.logger.trace('stopping web3 provider due to error');
+      
+      // prevent continuous polling errors
+      self.engine.stop();
     });
 
     self.engine.start();
-    self.web3.setProvider(self);
+  self.web3.setProvider(self);
 
     self.accounts = AccountParser.parseAccountsConfig(self.accountsConfig, self.web3, self.logger);
     self.addresses = [];

lib/processes/blockchainProcessLauncher.js

@@ -44,6 +44,14 @@ class BlockchainProcessLauncher {
       this.events.emit(constants.blockchain.blockchainReady);
     });
 
+    this.blockchainProcess.once('result', constants.blockchain.blockchainExit, () => {
+      // telle everyone that our blockchain process (ie geth) died
+      this.events.emit(constants.blockchain.blockchainExit);
+
+      // then kill off the blockchain process
+      this.blockchainProcess.kill();
+    });
+
     this.events.on('exit', () => {
       this.blockchainProcess.send('exit');
     });

package.json

@@ -79,7 +79,7 @@
     "uuid": "^3.2.1",
     "viz.js": "^1.8.1",
     "web3": "1.0.0-beta.34",
-    "embark-web3-provider-engine": "14.0.6",
+    "embark-web3-provider-engine": "14.0.7",
     "webpack": "^3.10.0",
     "window-size": "^1.1.0"
   },