fix: add server-side logging to AI tool routes (#23)

AI routes (remove-background, erase-object, ocr, blur-faces, upscale)
were silently swallowing errors - failures returned HTTP 422 to the
client but never appeared in server logs. This made it impossible for
self-hosters to diagnose issues like 504 timeouts from reverse proxies.

Adds request.log.info() at processing start (tool name, image size, key
settings) and request.log.error() in catch blocks, matching the existing
tool-factory pattern.

Co-authored-by: Siddharth Kumar Sah <siddharth123sk@gmail.com>

apps/api/src/routes/tools/blur-faces.ts

@@ -55,6 +55,15 @@ export function registerBlurFaces(app: FastifyInstance) {
 
     try {
       const settings = settingsRaw ? JSON.parse(settingsRaw) : {};
+      request.log.info(
+        {
+          toolId: "blur-faces",
+          imageSize: fileBuffer.length,
+          blurRadius: settings.blurRadius,
+          sensitivity: settings.sensitivity,
+        },
+        "Starting face blur",
+      );
 
       // Auto-orient to fix EXIF rotation before face detection
       fileBuffer = await autoOrient(fileBuffer);
@@ -111,6 +120,7 @@ export function registerBlurFaces(app: FastifyInstance) {
         faces: result.faces,
       });
     } catch (err) {
+      request.log.error({ err, toolId: "blur-faces" }, "Face blur failed");
       return reply.status(422).send({
         error: "Face blur failed",
         details: err instanceof Error ? err.message : "Unknown error",

apps/api/src/routes/tools/erase-object.ts

@@ -63,6 +63,10 @@ export function registerEraseObject(app: FastifyInstance) {
     }
 
     try {
+      request.log.info(
+        { toolId: "erase-object", imageSize: imageBuffer.length, maskSize: maskBuffer.length },
+        "Starting object erasure",
+      );
       const jobId = randomUUID();
       const workspacePath = await createWorkspace(jobId);
 
@@ -110,6 +114,7 @@ export function registerEraseObject(app: FastifyInstance) {
         processedSize: resultBuffer.length,
       });
     } catch (err) {
+      request.log.error({ err, toolId: "erase-object" }, "Object erasing failed");
       return reply.status(422).send({
         error: "Object erasing failed",
         details: err instanceof Error ? err.message : "Unknown error",

apps/api/src/routes/tools/ocr.ts

@@ -70,6 +70,15 @@ export function registerOcr(app: FastifyInstance) {
         return reply.status(400).send({ error: "Settings must be valid JSON" });
       }
 
+      request.log.info(
+        {
+          toolId: "ocr",
+          imageSize: fileBuffer.length,
+          engine: settings.engine,
+          language: settings.language,
+        },
+        "Starting OCR",
+      );
       const jobId = randomUUID();
       const workspacePath = await createWorkspace(jobId);
 
@@ -110,6 +119,7 @@ export function registerOcr(app: FastifyInstance) {
         engine: result.engine,
       });
     } catch (err) {
+      request.log.error({ err, toolId: "ocr" }, "OCR failed");
       return reply.status(422).send({
         error: "OCR failed",
         details: err instanceof Error ? err.message : "Unknown error",

apps/api/src/routes/tools/remove-background.ts

@@ -56,6 +56,10 @@ export function registerRemoveBackground(app: FastifyInstance) {
 
       try {
         const settings = settingsRaw ? JSON.parse(settingsRaw) : {};
+        request.log.info(
+          { toolId: "remove-background", imageSize: fileBuffer.length, model: settings.model },
+          "Starting background removal",
+        );
         const jobId = randomUUID();
         const workspacePath = await createWorkspace(jobId);
 
@@ -103,6 +107,7 @@ export function registerRemoveBackground(app: FastifyInstance) {
           processedSize: resultBuffer.length,
         });
       } catch (err) {
+        request.log.error({ err, toolId: "remove-background" }, "Background removal failed");
         return reply.status(422).send({
           error: "Background removal failed",
           details: err instanceof Error ? err.message : "Unknown error",

apps/api/src/routes/tools/upscale.ts

@@ -56,6 +56,10 @@ export function registerUpscale(app: FastifyInstance) {
     try {
       const settings = settingsRaw ? JSON.parse(settingsRaw) : {};
       const scale = Number(settings.scale) || 2;
+      request.log.info(
+        { toolId: "upscale", imageSize: fileBuffer.length, scale },
+        "Starting upscale",
+      );
 
       // Auto-orient to fix EXIF rotation before upscaling
       fileBuffer = await autoOrient(fileBuffer);
@@ -110,6 +114,7 @@ export function registerUpscale(app: FastifyInstance) {
         method: result.method,
       });
     } catch (err) {
+      request.log.error({ err, toolId: "upscale" }, "Upscaling failed");
       return reply.status(422).send({
         error: "Upscaling failed",
         details: err instanceof Error ? err.message : "Unknown error",