Merge pull request #79 from mkouba/issue-77-console-log-revert

stdio: redirect console logging to stderr
quarkiverse · Jan 21, 2025 · 74bafba · 74bafba
2 parents b1eb2f4 + 06ec40a
commit 74bafba
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diff --git a/docs/modules/ROOT/pages/index.adoc b/docs/modules/ROOT/pages/index.adoc
@@ -24,7 +24,7 @@ For instance, with Maven, add the following dependency to your POM file:
 </dependency>
 ----
 
-IMPORTANT: If you use the `stdio` transport then your app should not write anything to the standard output. Logging in the console is automatically disabled. And the standard output stream is set to "null" when the app is started by default. 
+IMPORTANT: If you use the `stdio` transport then your app should not write anything to the standard output. Quarkus console logging is automatically redirected to the standard error. And the standard output stream is set to "null" when the app is started by default. 
 
 If you want to use the https://modelcontextprotocol.io/docs/concepts/transports#server-sent-events-sse[HTTP/SSE] transport you'll need to add the `io.quarkiverse.mcp:quarkus-mcp-server-sse` extension to your build file first.
 For instance, with Maven, add the following dependency to your POM file:

diff --git a/...e/src/main/java/io/quarkiverse/mcp/server/stdio/runtime/StdioConfigBuilderCustomizer.java b/...e/src/main/java/io/quarkiverse/mcp/server/stdio/runtime/StdioConfigBuilderCustomizer.java
@@ -7,7 +7,7 @@
 import io.smallrye.config.SmallRyeConfigBuilderCustomizer;
 
 /**
- * Always disable console logging.
+ * Redirect console logging to {@code System#err} instead of {@code System#out}.
  * <p>
  * Originally, we tried to use the {@code RunTimeConfigurationDefaultBuildItem}. However, this build item has no effect unless a
  * Quarkus version with <a href="https://github.com/quarkusio/quarkus/pull/45431">a fix</a> is used.
@@ -18,8 +18,10 @@ public class StdioConfigBuilderCustomizer implements SmallRyeConfigBuilderCustom
     public void configBuilder(SmallRyeConfigBuilder builder) {
         builder.withSources(
                 new PropertiesConfigSource(
-                        Map.of("quarkus.log.console.enable", "false"),
-                        "mcp-stdio-config-source", 500));
+                        Map.of("quarkus.log.console.stderr", "true"),
+                        "mcp-stdio-config-source",
+                        // Keep the low ordinal so that users can override the config property
+                        50));
     }
 
 }