move vyper contract compile to static util function

Author: jrainville

lib/modules/vyper/index.js

@@ -12,6 +12,22 @@ class Vyper {
     embark.registerCompiler(".py", this.compile_vyper.bind(this));
   }
 
+  static compileVyperContract(filename, compileABI, callback) {
+    const params = compileABI ?  '-f json ' : '';
+    shelljs.exec(`vyper ${params}${filename}`, {silent: true}, (code, stdout, stderr) => {
+      if (stderr) {
+        return callback(stderr);
+      }
+      if (code !== 0) {
+        return callback(`Vyper exited with error code ${code}`);
+      }
+      if (!stdout) {
+        return callback('Execution returned no result');
+      }
+      callback(null, stdout.replace(/\n/g, ''));
+    });
+  }
+
   compile_vyper(contractFiles, cb) {
     let self = this;
     if (!contractFiles || !contractFiles.length) {
@@ -25,37 +41,24 @@ class Vyper {
         compiled_object[className] = {};
         async.parallel([
           function getByteCode(paraCb) {
-            shelljs.exec(`vyper ${file.filename}`, {silent: true}, (code, stdout, stderr) => {
-              if (stderr) {
-                return paraCb(stderr);
-              }
-              if (code !== 0) {
-                return paraCb(`Vyper exited with error code ${code}`);
-              }
-              if (!stdout) {
-                return paraCb('Execution returned no bytecode');
+            Vyper.compileVyperContract(file.filename, false, (err, byteCode) => {
+              if (err) {
+                return paraCb(err);
               }
-              const byteCode = stdout.replace(/\n/g, '');
               compiled_object[className].runtimeBytecode = byteCode;
               compiled_object[className].realRuntimeBytecode = byteCode;
               compiled_object[className].code = byteCode;
               paraCb();
             });
           },
           function getABI(paraCb) {
-            shelljs.exec(`vyper -f json ${file.filename}`, {silent: true}, (code, stdout, stderr) => {
-              if (stderr) {
-                return paraCb(stderr);
-              }
-              if (code !== 0) {
-                return paraCb(`Vyper exited with error code ${code}`);
-              }
-              if (!stdout) {
-                return paraCb('Execution returned no ABI');
+            Vyper.compileVyperContract(file.filename, true, (err, ABIString) => {
+              if (err) {
+                return paraCb(err);
               }
               let ABI = [];
               try {
-                ABI = JSON.parse(stdout.replace(/\n/g, ''));
+                ABI = JSON.parse(ABIString);
               } catch (e) {
                 return paraCb('ABI is not valid JSON');
               }
@@ -69,7 +72,6 @@ class Vyper {
         cb(err, compiled_object);
       });
   }
-
 }
 
 module.exports = Vyper;