error handling for webservice issues and unpublished packages

npm-manifest-check.py

@@ -1,6 +1,7 @@
 #!/usr/bin/env python3
 import requests
 import json
+import time
 
 # https://www.npmjs.com/package/darcyclarke-manifest-pkg/v/2.1.15/index
 # hex checksum = file name
@@ -13,7 +14,11 @@ def parse_manifest(pkg):
     parsed = json.loads(requests.get(url).text)
 
     # extract the interesting bits
+    try:
         latest_ver = parsed['dist-tags']['latest']
+    except KeyError:
+        print(f'Failed to find latest version for {pkg} - might have been unpublished?')
+        return None, None, None, None
     latest_manifest = parsed['versions'][latest_ver]
 
     try:
@@ -23,7 +28,7 @@ def parse_manifest(pkg):
     try:
         scripts = latest_manifest['scripts']
     except KeyError:
-        scripts = None
+        scripts = json.loads('{}')
     name = latest_manifest['name']
 
     return latest_ver, dependencies, scripts, name
@@ -33,12 +38,27 @@ def get_actual_manifest(pkg, ver):
     # get and parse the manifest as it would be installed
     # first, we need to find the package.json delivered with the package:
     index_url = 'https://www.npmjs.com/package/{}/v/{}/index'.format(pkg, ver)
+    while True:
+        try:
             index = json.loads(requests.get(index_url).text)
+            break
+        except json.decoder.JSONDecodeError:
+            print('Failed to get index from webservice, retrying...')
+            time.sleep(1)
+
     hexsum = index['files']['/package.json']['hex']
     manifest_url = 'https://www.npmjs.com/package/{}/file/{}'.format(pkg, hexsum)
 
-    # now we can parse it
+    # Sometimes the webservice seems to respond with an empty json - so this kludge got made:
+    while True:
+        try:
             manifest = json.loads(requests.get(manifest_url).text)
+            break
+        except json.decoder.JSONDecodeError:
+            print('Failed getting manifest JSON from webserver, retrying...')
+            time.sleep(1)
+
+    # now we can parse it
     version = manifest['version']
     try:
         dependencies = manifest['dependencies']
@@ -47,7 +67,7 @@ def get_actual_manifest(pkg, ver):
     try:
         scripts = manifest['scripts']
     except KeyError:
-        scripts = None
+        scripts = json.loads('{}')
     name = manifest['name']
 
     return version, dependencies, scripts, name
@@ -58,6 +78,9 @@ def main():
     mismatch = False
     pkg = sys.argv[1]
     reported_ver, reported_dependencies, reported_scripts, reported_name = parse_manifest(pkg)
+
+    if reported_ver == None:
+        sys.exit(2)
     actual_ver, actual_dependencies, actual_scripts, actual_name = get_actual_manifest(pkg, reported_ver)
 
     if actual_ver != reported_ver: