Check for gulp.js too. Warn about node and gulp.

code/extra_scripts.py

@@ -47,6 +47,15 @@ def print_filler(fill, color=Color.WHITE, err=False):
     out = sys.stderr if err else sys.stdout
     print(clr(color, fill * width), file=out)
 
+def VerboseWhereIs(env, prog, message, path=None):
+    result = env.WhereIs(prog=prog, path=path)
+    if not result:
+        if path:
+            prog = os.path.join(path, prog)
+        print_warning("'{}' {}".format(prog, message))
+    return result
+env.AddMethod(VerboseWhereIs)
+
 # ------------------------------------------------------------------------------
 # Callbacks
 # ------------------------------------------------------------------------------
@@ -109,14 +118,24 @@ def build_webui(source, target, env):
 env.Append(WEBUI_SOURCE="$PROJECT_DIR/html/")
 env.Append(WEBUI_HEADER="$PROJECT_DIR/espurna/static/index.html.gz.h")
 
-# check env.WhereIs("node_modules/gulp/bin/gulp.js") too
-if env.WhereIs("node"):
+have_node = env.VerboseWhereIs(
+    "node",
+    "is not installed"
+)
+
+have_gulp = env.VerboseWhereIs(
+    "gulp.js",
+    "is not installed (run 'npm install --only=dev')",
+    "node_modules/gulp/bin/"
+)
+
+if have_node and have_gulp:
     env.Depends("$WEBUI_HEADER", "$WEBUI_SOURCE")
     env.Depends(env.Alias("buildprog"), "$WEBUI_HEADER")
     cmd_webui = env.Command("$WEBUI_HEADER", "$WEBUI_SOURCE",
             build_webui, source_scanner=DirScanner())
     env.AlwaysBuild(env.Alias("build_webui", cmd_webui))
 else:
-    print_warning("Not building the web UI image ('node' does not exist in the path)")
+    print_warning("Not building the web UI bundle")
 
 env.AddPostAction("$BUILD_DIR/${PROGNAME}.bin", check_size)