assign roles so ipc connections don't conflict; fallback if can't connect to ipc

lib/core/engine.js

@@ -183,7 +183,7 @@ class Engine {
       compiler.compile_contracts(contractFiles, cb);
     });
 
-    this.ipc = new IPC({logger: this.logger});
+    this.ipc = new IPC({logger: this.logger, ipcRole: options.ipcRole});
     this.registerModule('solidity', {useIpc: options.useIpc, ipc: this.ipc});
     this.registerModule('vyper');
     this.registerModule('profiler');

lib/core/ipc.js

@@ -6,13 +6,31 @@ class IPC {
   constructor(options) {
     this.logger = options.logger;
     this.socketPath = options.socketPath || fs.dappPath(".embark/embark.ipc");
+    this.ipcRole = options.ipcRole || "server";
     ipc.config.silent = true;
+    this.connected = false;
   }
 
   connect(done) {
+    const self = this;
     function connecting(socket) {
+      let connectedBefore = false, alreadyDisconnected = false;;
       ipc.of['embark'].on('connect',function() {
-        done();
+        connectedBefore = true;
+        if (!alreadyDisconnected) {
+          self.connected = true;
+          done();
+        }
+      });
+      ipc.of['embark'].on('disconnect',function() {
+        self.connected = false;
+        ipc.disconnect('embark');
+
+        // we only want to trigger the error callback the first time
+        if (!connectedBefore && !alreadyDisconnected) {
+          alreadyDisconnected = true;
+          done(new Error("no connection found"));
+        }
       });
     }
 
@@ -59,6 +77,14 @@ class IPC {
     ipc.of['embark'].emit('message', {action: action, message: data});
   }
 
+  isClient() {
+    return this.ipcRole === 'client';
+  }
+
+  isServer() {
+    return this.ipcRole === 'server';
+  }
+
 }
 
 module.exports = IPC;

lib/modules/solidity/solcW.js

@@ -10,7 +10,6 @@ class SolcW {
   constructor(options) {
     this.logger = options.logger;
     this.events = options.events;
-    this.useIpc = options.useIpc;
     this.ipc = options.ipc;
     this.compilerLoaded = false;
     this.solcProcess = null;
@@ -18,11 +17,21 @@ class SolcW {
 
   load_compiler(done) {
     const self = this;
-    if (self.useIpc) {
-      self.compilerLoaded = true;
-
-      return self.ipc.connect(done);
+    if (self.ipc.isClient()) {
+      return self.ipc.connect((err) => {
+        if (err) {
+          return self.load_compiler_internally(done);
+        }
+        self.compilerLoaded = true;
+        done();
+      });
     }
+
+    self.load_compiler_internally(done);
+  }
+
+  load_compiler_internally(done) {
+    const self = this;
     if (this.compilerLoaded) {
       return done();
     }
@@ -38,8 +47,10 @@ class SolcW {
       done();
     });
 
-    this.ipc.serve();
-    this.ipc.on('compile', self.compile.bind(this));
+    if (this.ipc.isServer()) {
+      this.ipc.serve();
+      this.ipc.on('compile', self.compile.bind(this));
+    }
 
     this.events.request("version:get:solc", function(solcVersion) {
       if (solcVersion === currentSolcVersion) {
@@ -64,7 +75,7 @@ class SolcW {
     const id = uuid();
     let a = new Date();
 
-    if (this.useIpc) {
+    if (this.ipc.isClient() && this.ipc.connected) {
       return this.ipc.request('compile', jsonObj, done);
     }
 

lib/tests/test.js

@@ -65,7 +65,7 @@ class Test {
     });
     this.engine.startService("deployment", {
       trackContracts: false,
-      useIpc: true
+      ipcRole: 'client'
     });
     this.engine.startService("codeGenerator");
   }