custom prefixes

Author: guybedford

src/workerd/io/worker-fs.c++

@@ -1764,16 +1764,13 @@ void writeStdio(jsg::Lock& js, VirtualFileSystem::Stdio type, kj::ArrayPtr<const
       auto methodFunc = jsg::JsFunction(methodVal.As<v8::Function>());
 
       kj::String outputStr;
-      auto processStdioPrefixed = Worker::Isolate::from(js).getProcessStdioPrefixed();
-      if (processStdioPrefixed) {
-        if (endPos == 0) {
-          methodFunc.call(js, console,
-              js.str(type == VirtualFileSystem::Stdio::OUT ? "stdout:"_kj : "stderr:"_kj));
-        } else {
-          methodFunc.call(js, console,
-              js.str(type == VirtualFileSystem::Stdio::OUT ? "stdout:"_kj : "stderr:"_kj),
-              js.str(chars.first(endPos)));
-        }
+      auto isolate = &Worker::Isolate::from(js);
+      auto prefix = type == VirtualFileSystem::Stdio::OUT ? isolate->getStdoutPrefix()
+                                                          : isolate->getStderrPrefix();
+      if (endPos == 0) {
+        methodFunc.call(js, console, js.str(prefix));
+      } else if (prefix.size() > 0) {
+        methodFunc.call(js, console, js.str(kj::str(prefix, " "_kj, chars.first(endPos))));
       } else {
         methodFunc.call(js, console, js.str(chars.first(endPos)));
       }

src/workerd/io/worker.h

@@ -123,6 +123,28 @@ class Worker: public kj::AtomicRefcounted {
     ConsoleMode consoleMode = Worker::ConsoleMode::STDOUT;
     StructuredLogging structuredLogging = StructuredLogging::NO;
     ProcessStdioPrefixed processStdioPrefixed = ProcessStdioPrefixed::YES;
+    kj::String stdoutPrefix = kj::str("stdout:"_kj);
+    kj::String stderrPrefix = kj::str("stderr:"_kj);
+
+    LoggingOptions() = default;
+    LoggingOptions(LoggingOptions&&) = default;
+    LoggingOptions& operator=(LoggingOptions&&) = default;
+
+    LoggingOptions(const LoggingOptions& other)
+        : consoleMode(other.consoleMode),
+          structuredLogging(other.structuredLogging),
+          processStdioPrefixed(other.processStdioPrefixed),
+          stdoutPrefix(kj::str(other.stdoutPrefix)),
+          stderrPrefix(kj::str(other.stderrPrefix)) {}
+
+    LoggingOptions& operator=(const LoggingOptions& other) {
+      consoleMode = other.consoleMode;
+      structuredLogging = other.structuredLogging;
+      processStdioPrefixed = other.processStdioPrefixed;
+      stdoutPrefix = kj::str(other.stdoutPrefix);
+      stderrPrefix = kj::str(other.stderrPrefix);
+      return *this;
+    }
   };
 
   explicit Worker(kj::Own<const Script> script,
@@ -453,8 +475,12 @@ class Worker::Isolate: public kj::AtomicRefcounted {
   bool isInspectorEnabled() const;
 
   // Get the process stdio prefixed setting from logging options
-  inline ProcessStdioPrefixed getProcessStdioPrefixed() const {
-    return loggingOptions.processStdioPrefixed;
+  inline kj::StringPtr getStdoutPrefix() const {
+    return loggingOptions.stdoutPrefix;
+  }
+
+  inline kj::StringPtr getStderrPrefix() const {
+    return loggingOptions.stderrPrefix;
   }
 
   // Represents a weak reference back to the isolate that code within the isolate can use as an

src/workerd/server/server.c++

@@ -5114,8 +5114,11 @@ kj::Promise<void> Server::run(
 
   // Update logging settings from config
   loggingOptions.structuredLogging = StructuredLogging(config.getStructuredLogging());
-  loggingOptions.processStdioPrefixed =
-      config.getProcessStdioPrefixed() ? ProcessStdioPrefixed::YES : ProcessStdioPrefixed::NO;
+  if (config.hasLogging()) {
+    auto logging = config.getLogging();
+    loggingOptions.stdoutPrefix = kj::str(logging.getStdoutPrefix());
+    loggingOptions.stderrPrefix = kj::str(logging.getStderrPrefix());
+  }
 
   kj::HttpHeaderTable::Builder headerTableBuilder;
   globalContext = kj::heap<GlobalContext>(*this, v8System, headerTableBuilder);
@@ -5509,8 +5512,11 @@ kj::Promise<bool> Server::test(jsg::V8System& v8System,
     kj::StringPtr entrypointPattern) {
   // Update logging settings from config
   loggingOptions.structuredLogging = StructuredLogging(config.getStructuredLogging());
-  loggingOptions.processStdioPrefixed =
-      config.getProcessStdioPrefixed() ? ProcessStdioPrefixed::YES : ProcessStdioPrefixed::NO;
+  if (config.hasLogging()) {
+    auto logging = config.getLogging();
+    loggingOptions.stdoutPrefix = kj::str(logging.getStdoutPrefix());
+    loggingOptions.stderrPrefix = kj::str(logging.getStderrPrefix());
+  }
 
   kj::HttpHeaderTable::Builder headerTableBuilder;
   globalContext = kj::heap<GlobalContext>(*this, v8System, headerTableBuilder);

src/workerd/server/workerd.capnp

@@ -91,10 +91,17 @@ struct Config {
   # This affects the format of logs from KJ_LOG and exception reporting as well as js logs.
   # This won't work for logs coming from service worker syntax workers with the old module registry.
 
-  processStdioPrefixed @6 :Bool = true;
-  # Whether to prefix process.stdout and process.stderr output with "stdout: " or "stderr: "
-  # Default is true.
-  # Set to false for backwards compat with unprefixed output.
+  logging @6 : LoggingOptions;
+}
+
+struct LoggingOptions {
+  stdoutPrefix @0 :Text = "stdout:";
+  # Prefix process.stdout output with "stdout: "
+  # Can be set to the empty string or a custom prefix to customize.
+
+  stderrPrefix @1 :Text = "stderr:";
+  # Prefix process.stderr output with "stderr: "
+  # Can be set to the empty string or a custom prefix to customize.
 }
 
 # ========================================================================================