From b69d4f29e5ad4153be15a928ed3820a17d2cd07b Mon Sep 17 00:00:00 2001
From: Rhys Arkins <rhys@arkins.net>
Date: Thu, 25 Jun 2020 09:34:41 +0200
Subject: [PATCH] refactor: add try/catch and logging to datasource wrapper

---
 lib/datasource/index.spec.ts | 16 ++++++------
 lib/datasource/index.ts      | 47 +++++++++++++++++++++++++++---------
 2 files changed, 44 insertions(+), 19 deletions(-)

diff --git a/lib/datasource/index.spec.ts b/lib/datasource/index.spec.ts
index 160a5bb30f50a0..cce29d3bfb255b 100644
--- a/lib/datasource/index.spec.ts
+++ b/lib/datasource/index.spec.ts
@@ -143,20 +143,20 @@ describe('datasource/index', () => {
       })
     ).rejects.toThrow(EXTERNAL_HOST_ERROR);
   });
-  it('hunts registries and passes on error', async () => {
+  it('hunts registries and returns null', async () => {
     packagistDatasource.getReleases.mockImplementationOnce(() => {
       throw new Error('a');
     });
     packagistDatasource.getReleases.mockImplementationOnce(() => {
       throw new Error('b');
     });
-    await expect(
-      datasource.getPkgReleases({
+    expect(
+      await datasource.getPkgReleases({
         datasource: datasourcePackagist.id,
         depName: 'something',
         registryUrls: ['https://reg1.com', 'https://reg2.io'],
       })
-    ).rejects.toThrow('b');
+    ).toBeNull();
   });
   it('merges registries and returns success', async () => {
     mavenDatasource.getReleases.mockResolvedValueOnce({
@@ -185,20 +185,20 @@ describe('datasource/index', () => {
       })
     ).rejects.toThrow(EXTERNAL_HOST_ERROR);
   });
-  it('merges registries and passes on error', async () => {
+  it('merges registries and returns null for error', async () => {
     mavenDatasource.getReleases.mockImplementationOnce(() => {
       throw new Error('a');
     });
     mavenDatasource.getReleases.mockImplementationOnce(() => {
       throw new Error('b');
     });
-    await expect(
-      datasource.getPkgReleases({
+    expect(
+      await datasource.getPkgReleases({
         datasource: datasourceMaven.id,
         depName: 'something',
         registryUrls: ['https://reg1.com', 'https://reg2.io'],
       })
-    ).rejects.toThrow('b');
+    ).toBeNull();
   });
   it('trims sourceUrl', async () => {
     npmDatasource.getReleases.mockResolvedValue({
diff --git a/lib/datasource/index.ts b/lib/datasource/index.ts
index 92a5d9ac6df134..bc3fe6d73bcb2a 100644
--- a/lib/datasource/index.ts
+++ b/lib/datasource/index.ts
@@ -30,6 +30,18 @@ function load(datasource: string): Promise<Datasource> {
 
 type GetReleasesInternalConfig = GetReleasesConfig & GetPkgReleasesConfig;
 
+// istanbul ignore next
+function logError(datasource, lookupName, err): void {
+  const { statusCode, url } = err;
+  if (statusCode === 404) {
+    logger.debug({ datasource, lookupName, url }, 'Datasource 404');
+  } else if (statusCode === 401 || statusCode === 403) {
+    logger.debug({ datasource, lookupName, url }, 'Datasource unauthorized');
+  } else {
+    logger.debug({ datasource, lookupName, err }, 'Datasource unknown error');
+  }
+}
+
 async function getRegistryReleases(
   datasource,
   config: GetReleasesConfig,
@@ -39,7 +51,7 @@ async function getRegistryReleases(
   return res;
 }
 
-function firstRegistry(
+async function firstRegistry(
   config: GetReleasesInternalConfig,
   datasource: Datasource,
   registryUrls: string[]
@@ -51,7 +63,16 @@ function firstRegistry(
     );
   }
   const registryUrl = registryUrls[0];
-  return getRegistryReleases(datasource, config, registryUrl);
+  try {
+    const res = await getRegistryReleases(datasource, config, registryUrl);
+    return res;
+  } catch (err) /* istanbul ignore next */ {
+    if (err instanceof ExternalHostError) {
+      throw err;
+    }
+    logError(datasource.id, config.lookupName, err);
+    return null;
+  }
 }
 
 async function huntRegistries(
@@ -76,11 +97,13 @@ async function huntRegistries(
       logger.trace({ err }, 'datasource hunt failure');
     }
   }
-  if (res === undefined && datasourceError) {
-    // if we failed to get a result and also got an error then throw it
-    throw datasourceError;
+  if (res) {
+    return res;
+  }
+  if (datasourceError) {
+    logError(datasource.id, config.lookupName, datasourceError);
   }
-  return res;
+  return null;
 }
 
 async function mergeRegistries(
@@ -108,10 +131,6 @@ async function mergeRegistries(
       logger.trace({ err }, 'datasource merge failure');
     }
   }
-  if (combinedRes === undefined && datasourceError) {
-    // if we failed to get a result and also got an error then throw it
-    throw datasourceError;
-  }
   // De-duplicate releases
   if (combinedRes?.releases?.length) {
     const seenVersions = new Set<string>();
@@ -123,7 +142,13 @@ async function mergeRegistries(
       return true;
     });
   }
-  return combinedRes;
+  if (combinedRes) {
+    return combinedRes;
+  }
+  if (datasourceError) {
+    logError(datasource.id, config.lookupName, datasourceError);
+  }
+  return null;
 }
 
 function resolveRegistryUrls(