Only install node/npm/bower if not installed globally

build/_bower.shade

@@ -1,9 +1,13 @@
 default currentDir = '${Directory.GetCurrentDirectory()}'
 default nodeDir = '${Path.Combine(currentDir, "bin", "nodejs")}'
-var bowerInstalled = '${Directory.Exists(Path.Combine(nodeDir, "node_modules", "bower"))}'
 
-- // Install bower locally
-npm npmCommand='install --prefix ${nodeDir} bower' if='!bowerInstalled' once='installBower'
+var bowerGloballyInstalled = '${TestCommand("bower --version")}'
+var bowerInstalled = '${Directory.Exists(Path.Combine(nodeDir, "node_modules", "bower"))}'
+var bowerCmd = '${ bowerGloballyInstalled ? "bower" : Path.Combine(nodeDir, "node_modules", "bower", "bin", "bower") }'
+
+- // Install bower locally if not already installed either globally or locally
+npm npmCommand='install --prefix ${nodeDir} bower' if='!(bowerGloballyInstalled || bowerInstalled)' once='installBower'
 
 - // Run bower
-node nodeCommand='${Path.Combine(nodeDir, "node_modules", "bower", "bin", "bower")} ${bowerCommand}' workingdir='${bowerDir}'
+exec program='${bowerCmd}' commandline='${bowerCommand}' if='bowerGloballyInstalled'
+node nodeCommand='${bowerCmd} ${bowerCommand}' workingdir='${bowerDir}' if='!bowerGloballyInstalled'

build/_k-standard-goals.shade

@@ -115,6 +115,33 @@ functions @{
                       .Select(p => Path.GetDirectoryName(p))
                       .Distinct();
     }
+    bool TestCommand(string program, string commandline = null) {
+      // Tests whether a given command succeeds at the command line.
+      // Useful for testing whether a given command is installed and on the path, e.g. node
+      var processStartInfo = new ProcessStartInfo {
+        UseShellExecute = false,
+        WorkingDirectory = Directory.GetCurrentDirectory(),
+        FileName = program,
+        Arguments = commandline,
+      };
+      try {
+        Log.Info(string.Format("Testing for command: {0} {1}", program, commandline));
+        var process = Process.Start(processStartInfo);
+        process.WaitForExit();
+        if (process.ExitCode == 0) {
+          Log.Info("   command found");
+          return true;
+        }
+        else {
+          Log.Warn("   command not found");
+          return false;
+        }
+      }
+      catch (Exception) {
+        Log.Warn("   command not found");
+        return false;
+      }
+    }
 }
 
 macro name='Exec' program='string' commandline='string'

build/_node-install.shade

@@ -10,13 +10,14 @@ default nodeVer = '0.10.28'
 default npmVer = '1.4.9'
 default nodeExeSha = '628FFD6C3577068C00CEC9F6F897F0EC8F5212D9'
 default nodeInstallDir = '${Path.Combine(binDir, "nodejs")}'
+default nodeGloballyInstalled = '${TestCommand("node --version")}'
 
 var nodeExe = 'node.exe'
 var npmZip = 'npm-${npmVer}.zip'
 var nodeDist = 'http://nodejs.org/dist/'
 var nodeUrl = '${nodeDist}v${nodeVer}/${nodeExe}'
 var npmUrl = '${nodeDist}npm/${npmZip}'
-var doInstall = '${!File.Exists(nodeInstallDir)}'
+var doInstall = '${!nodeGloballyInstalled && !Directory.Exists(nodeInstallDir)}'
 var nodeInstallExePath = '${Path.Combine(nodeInstallDir, nodeExe)}'
 var npmInstallZipPath = '${Path.Combine(nodeInstallDir, npmZip)}'
 

build/_node.shade

@@ -1,6 +1,8 @@
 default currentDir = '${Directory.GetCurrentDirectory()}'
 default nodeDir = '${Path.Combine(currentDir, "bin", "node")}'
-var nodeExePath = '${Path.Combine(nodeDir, "node.exe")}'
+default nodeGloballyInstalled = '${TestCommand("node --version")}'
+
+var nodeExePath = '${ nodeGloballyInstalled ? "node" : Path.Combine(nodeDir, "node.exe") }'
 
 node-install once='installNode'
 exec program='${nodeExePath}' commandline='${nodeCommand}'

build/_npm.shade

@@ -1,7 +1,9 @@
 default currentDir = '${Directory.GetCurrentDirectory()}'
 default nodeDir = '${Path.Combine(currentDir, "bin", "nodejs")}'
 default npmDir = '${currentDir}'
-var npmCmd = '${Path.Combine(nodeDir, "npm.cmd")}'
+
+var npmGloballyInstalled = '${TestCommand("npm --version")}'
+var npmCmd = '${ npmGloballyInstalled ? "npm" : Path.Combine(nodeDir, "npm.cmd") }'
 
 node-install once='installNode'
 exec program='${npmCmd}' commandline='${npmCommand}' workingdir='${npmDir}'