chore: Refactor connection test in main and fixed HTTP Server only taking a single connection (fixes #134)

CHANGELOG.md

@@ -1,5 +1,7 @@
 # @dynatrace-oss/dynatrace-mcp-server
 
+- Fixed an issue with stateless HTTP server only taking a single connection
+
 ## Unreleased Changes
 
 ## 0.6.0 (Release Candidate 1)

README.md

@@ -288,19 +288,6 @@ npx -y @dynatrace-oss/dynatrace-mcp-server@latest --version
 }
 ```
 
-**Configuration for MCP clients that support HTTP transport:**
-
-```json
-{
-  "mcpServers": {
-    "dynatrace-http": {
-      "url": "http://localhost:3000",
-      "transport": "http"
-    }
-  }
-}
-```
-
 ### Rule File
 
 For efficient result retrieval from Dynatrace, please consider creating a rule file (e.g., [.github/copilot-instructions.md](https://docs.github.com/en/copilot/how-tos/configure-custom-instructions/add-repository-instructions), [.amazonq/rules/](https://docs.aws.amazon.com/amazonq/latest/qdeveloper-ug/context-project-rules.html)), instructing coding agents on how to get more details for your component/app/service. Here is an example for [easytrade](https://github.com/Dynatrace/easytrade), please adapt the names and filters to fit your use-cases and components:

src/index.ts

@@ -83,21 +83,18 @@ function handleClientRequestError(error: ClientRequestError): string {
   return `Client Request Error: ${error.message} with HTTP status: ${error.response.status}. ${additionalErrorInformation} (body: ${JSON.stringify(error.body)})`;
 }
 
-const main = async () => {
-  // read Environment variables
-  let dynatraceEnv: DynatraceEnv;
-  try {
-    dynatraceEnv = getDynatraceEnv();
-  } catch (err) {
-    console.error((err as Error).message);
-    process.exit(1);
-  }
-  console.error(`Initializing Dynatrace MCP Server v${getPackageJsonVersion()}...`);
-  const { oauthClientId, oauthClientSecret, dtEnvironment, dtPlatformToken, slackConnectionId } = dynatraceEnv;
-
-  // Test connection on startup
+/**
+ * Try to connect to Dynatrace environment with retries and exponential backoff.
+ */
+async function retryTestDynatraceConnection(
+  dtEnvironment: string,
+  oauthClientId?: string,
+  oauthClientSecret?: string,
+  dtPlatformToken?: string,
+) {
   let retryCount = 0;
-  const maxRetries = 5;
+  const maxRetries = 3; // Max retries
+  const delayMs = 2000; // Initial delay of 2 seconds
   while (true) {
     try {
       console.error(
@@ -116,14 +113,42 @@ const main = async () => {
       retryCount++;
       if (retryCount >= maxRetries) {
         console.error(`Fatal: Maximum number of connection retries (${maxRetries}) exceeded. Exiting.`);
-        process.exit(1);
+        throw new Error(
+          `Failed to connect to Dynatrace environment ${dtEnvironment} after ${maxRetries} attempts. Most likely your configuration is incorrect. Last error: ${error.message}`,
+          { cause: error },
+        );
       }
-      const delay = Math.pow(2, retryCount) * 1000; // Exponential backoff
+      const delay = Math.pow(2, retryCount) * delayMs; // Exponential backoff
       console.error(`Retrying in ${delay / 1000} seconds...`);
       await new Promise((resolve) => setTimeout(resolve, delay));
     }
   }
+}
+
+const main = async () => {
+  console.error(`Initializing Dynatrace MCP Server v${getPackageJsonVersion()}...`);
 
+  // read Environment variables
+  let dynatraceEnv: DynatraceEnv;
+  try {
+    dynatraceEnv = getDynatraceEnv();
+  } catch (err) {
+    console.error((err as Error).message);
+    process.exit(1);
+  }
+
+  // Unpack environment variables
+  const { oauthClientId, oauthClientSecret, dtEnvironment, dtPlatformToken, slackConnectionId } = dynatraceEnv;
+
+  // Test connection on startup
+  try {
+    await retryTestDynatraceConnection(dtEnvironment, oauthClientId, oauthClientSecret, dtPlatformToken);
+  } catch (err) {
+    console.error((err as Error).message);
+    process.exit(2);
+  }
+
+  // Ready to start the server
   console.error(`Starting Dynatrace MCP Server v${getPackageJsonVersion()}...`);
 
   // Initialize usage tracking
@@ -827,15 +852,26 @@ const main = async () => {
   const httpPort = parseInt(options.port, 10);
   const host = options.host || '0.0.0.0';
 
+  // HTTP server mode (Stateless)
   if (httpMode) {
-    // HTTP server mode
-    const httpTransport = new StreamableHTTPServerTransport({
-      sessionIdGenerator: () => randomUUID(),
-    });
-
     const httpServer = createServer(async (req: IncomingMessage, res: ServerResponse) => {
       // Parse request body for POST requests
       let body: unknown;
+      // Create a new Stateless HTTP Transport
+      const httpTransport = new StreamableHTTPServerTransport({
+        sessionIdGenerator: undefined, // No Session ID needed
+      });
+
+      res.on('close', () => {
+        // close transport and server, but not the httpServer itself
+        httpTransport.close();
+        server.close();
+      });
+
+      // Connecting MCP-server to HTTP transport
+      await server.connect(httpTransport);
+
+      // Handle POST Requests for this endpoint
       if (req.method === 'POST') {
         const chunks: Buffer[] = [];
         for await (const chunk of req) {
@@ -854,9 +890,6 @@ const main = async () => {
       await httpTransport.handleRequest(req, res, body);
     });
 
-    console.error('Connecting server to HTTP transport...');
-    await server.connect(httpTransport);
-
     // Start HTTP Server on the specified host and port
     httpServer.listen(httpPort, host, () => {
       console.error(`Dynatrace MCP Server running on HTTP at http://${host}:${httpPort}`);