fix(lambda-tiler): Catch the error code while reading the config file…

… in api. BM-898 (#2969)

#### Description
When failed to get config file from s3, return correct error code in
logs and remove the 500 error in #proj-basemaps-alerts


#### Intention
Catch the error from `fsa.readJson(config)`, and throw correct error
code and message.



#### Checklist
- [X] Tests updated
- [ ] Docs updated
- [X] Issue linked in Title

packages/lambda-tiler/src/util/__test__/config.loader.test.ts

@@ -82,8 +82,8 @@ o.spec('ConfigLoader', () => {
       .catch((e) => e);
 
     o(error instanceof LambdaHttpResponse).equals(true);
-    o((error as LambdaHttpResponse).status).equals(404);
-    o((error as LambdaHttpResponse).statusDescription).equals(`Config not found at ${location}`);
+    o((error as LambdaHttpResponse).status).equals(400);
+    o((error as LambdaHttpResponse).statusDescription).equals(`Invalid config location at ${location}`);
   });
 
   o('should get expected config file', async () => {
@@ -113,4 +113,17 @@ o.spec('ConfigLoader', () => {
 
     o(await provider.Imagery.get('topographic')).deepEquals(await expectedConfig.Imagery.get('topographic'));
   });
+
+  const deletedLocation = 'memory://linz-basemaps/config-deleted.json';
+  o('should Error 400 if config file not exists', async () => {
+    const error = await ConfigLoader.load(
+      mockUrlRequest('/v1/tiles/🦄 🌈/NZTM2000Quad/tile.json', `?config=${deletedLocation}`, Api.header),
+    )
+      .then(() => null)
+      .catch((e) => e);
+
+    o(error instanceof LambdaHttpResponse).equals(true);
+    o((error as LambdaHttpResponse).status).equals(400);
+    o((error as LambdaHttpResponse).statusDescription).equals(`Invalid config location at ${deletedLocation}`);
+  });
 });

packages/lambda-tiler/src/util/config.cache.ts

@@ -5,9 +5,10 @@ import { SwappingLru } from './swapping.lru.js';
 class LruConfig {
   configProvider: Promise<ConfigProviderMemory | null>;
 
-  constructor(config: Promise<ConfigBundled>) {
+  constructor(config: Promise<ConfigBundled | null>) {
     this.configProvider = config
       .then((c) => {
+        if (c == null) return null;
         const configProvider = ConfigProviderMemory.fromJson(c);
         configProvider.createVirtualTileSets();
         return configProvider;
@@ -33,7 +34,9 @@ export class ConfigCache {
   get(location: string): Promise<ConfigProviderMemory | null> {
     const existing = this.cache.get(location)?.configProvider;
     if (existing != null) return existing;
-    const configJson = fsa.readJson<ConfigBundled>(location);
+    const configJson = fsa.readJson<ConfigBundled>(location).catch(() => {
+      return null;
+    });
     const config = new LruConfig(configJson);
     this.cache.set(location, config);
     return config.configProvider;

packages/lambda-tiler/src/util/config.loader.ts

@@ -48,7 +48,7 @@ export class ConfigLoader {
     req.timer.start('config:load');
     return CachedConfig.get(configLocation).then((f) => {
       req.timer.end('config:load');
-      if (f == null) throw new LambdaHttpResponse(404, `Config not found at ${configLocation}`);
+      if (f == null) throw new LambdaHttpResponse(400, `Invalid config location at ${configLocation}`);
       return f;
     });
   }