From 4d207ad3f993a78856710ff04c92c0b8c534f5e5 Mon Sep 17 00:00:00 2001
From: tiennm99 <tiennm99@outlook.com>
Date: Sat, 15 Nov 2025 20:27:23 +0700
Subject: [PATCH] feat: init

---
 index.js      | 143 ++++++++++++++++++++++++++++++++++++++++++++++++++
 package.json  |   5 ++
 wrangler.toml |   3 ++
 3 files changed, 151 insertions(+)
 create mode 100644 index.js
 create mode 100644 package.json
 create mode 100644 wrangler.toml

diff --git a/index.js b/index.js
new file mode 100644
index 0000000..cb43efe
--- /dev/null
+++ b/index.js
@@ -0,0 +1,143 @@
+// Cloudflare Worker to forward logs to Grafana Cloud Loki
+
+async function handleRequest(request, env) {
+  const url = new URL(request.url);
+
+  // Redirect to GitHub repo for documentation
+  if (request.method === 'GET') {
+    return Response.redirect('https://github.com/tiennnm99/miti-loki', 302);
+  }
+
+  // Only handle POST requests
+  if (request.method !== 'POST') {
+    return new Response('Method not allowed. Please use POST.', {
+      status: 405,
+      headers: {
+        'Access-Control-Allow-Origin': '*',
+      }
+    });
+  }
+
+  // Validate environment variables
+  if (!env.LOKI_HOST || !env.LOKI_USERNAME || !env.LOKI_PASSWORD) {
+    return new Response('Server configuration error: Missing Loki credentials', {
+      status: 500,
+      headers: {
+        'Access-Control-Allow-Origin': '*',
+      }
+    });
+  }
+
+  try {
+    // Read the request body
+    const body = await request.text();
+
+    // Validate that body is not empty
+    if (!body) {
+      return new Response('Request body is required', {
+        status: 400,
+        headers: {
+          'Access-Control-Allow-Origin': '*',
+        }
+      });
+    }
+
+    // Validate JSON format
+    try {
+      const jsonBody = JSON.parse(body);
+      if (!jsonBody.streams || !Array.isArray(jsonBody.streams)) {
+        return new Response('Invalid format: "streams" array is required', {
+          status: 400,
+          headers: {
+            'Access-Control-Allow-Origin': '*',
+          }
+        });
+      }
+    } catch (parseError) {
+      return new Response(`Invalid JSON: ${parseError.message}`, {
+        status: 400,
+        headers: {
+          'Access-Control-Allow-Origin': '*',
+        }
+      });
+    }
+
+    // Construct Loki URL
+    const lokiPort = env.LOKI_PORT || '443';
+    const protocol = lokiPort === '443' ? 'https' : 'http';
+    const lokiUrl = `${protocol}://${env.LOKI_HOST}:${lokiPort}/loki/api/v1/push`;
+
+    // Create Basic Auth header
+    const auth = btoa(`${env.LOKI_USERNAME}:${env.LOKI_PASSWORD}`);
+
+    // Forward request to Loki
+    const lokiResponse = await fetch(lokiUrl, {
+      method: 'POST',
+      headers: {
+        'Content-Type': 'application/json',
+        'Authorization': `Basic ${auth}`,
+      },
+      body: body,
+    });
+
+    // Get response text
+    const responseText = await lokiResponse.text();
+
+    // Return the response from Loki with CORS headers
+    return new Response(responseText, {
+      status: lokiResponse.status,
+      statusText: lokiResponse.statusText,
+      headers: {
+        'Content-Type': lokiResponse.headers.get('Content-Type') || 'text/plain',
+        'Access-Control-Allow-Origin': '*',
+        'Access-Control-Allow-Methods': 'POST, OPTIONS',
+        'Access-Control-Allow-Headers': 'Content-Type',
+      },
+    });
+
+  } catch (error) {
+    return new Response(`Error forwarding to Loki: ${error.message}`, {
+      status: 500,
+      headers: {
+        'Access-Control-Allow-Origin': '*',
+      }
+    });
+  }
+}
+
+// Handle OPTIONS requests for CORS
+function handleOptions(request) {
+  const corsHeaders = {
+    'Access-Control-Allow-Origin': '*',
+    'Access-Control-Allow-Methods': 'POST, OPTIONS',
+    'Access-Control-Allow-Headers': 'Content-Type',
+    'Access-Control-Max-Age': '86400',
+  };
+
+  return new Response(null, {
+    status: 204,
+    headers: corsHeaders,
+  });
+}
+
+// Main event listener for the worker
+addEventListener('fetch', event => {
+  const request = event.request;
+
+  // Handle CORS preflight requests
+  if (request.method === 'OPTIONS') {
+    event.respondWith(handleOptions(request));
+  } else {
+    event.respondWith(handleRequest(request, event.env || {}));
+  }
+});
+
+// Export for ES modules (newer Workers format)
+export default {
+  async fetch(request, env) {
+    if (request.method === 'OPTIONS') {
+      return handleOptions(request);
+    }
+    return handleRequest(request, env);
+  }
+};
diff --git a/package.json b/package.json
new file mode 100644
index 0000000..63e8a42
--- /dev/null
+++ b/package.json
@@ -0,0 +1,5 @@
+{
+  "devDependencies": {
+    "wrangler": "^4.0.0"
+  }
+}
diff --git a/wrangler.toml b/wrangler.toml
new file mode 100644
index 0000000..396fe37
--- /dev/null
+++ b/wrangler.toml
@@ -0,0 +1,3 @@
+name = "miti-loki"
+main = "index.js"
+compatibility_date = "2024-12-31"