CFE-4540: Add user-friendly errors in failing network conditions

cfbs/analyze.py

@@ -14,9 +14,9 @@
     fetch_url,
     file_sha256,
     get_json,
-    get_or_read_json,
     immediate_subdirectories,
     mkdir,
+    read_json,
     user_error,
 )
 
@@ -131,7 +131,12 @@ def mpf_vcf_dicts(offline=False):
             "https://api.github.com/repos/" + REPO_OWNERNAME + "/releases/latest"
         )
 
-        latest_release_data = get_json(LATEST_RELEASE_API_URL)
+        try:
+            latest_release_data = get_json(LATEST_RELEASE_API_URL)
+        except FetchError as e:
+            user_error(
+                "Downloading CFEngine release information failed - check your Wi-Fi / network settings."
+            )
 
         latest_release_name = latest_release_data["name"]
         ri_archive_url = REPO_URL + "/archive/refs/tags/" + latest_release_name + ".zip"
@@ -169,13 +174,14 @@ def mpf_vcf_dicts(offline=False):
     mpf_checkfiles_json_path = os.path.join(mpf_vcf_path, "checksums.json")
     mpf_files_json_path = os.path.join(mpf_vcf_path, "files.json")
 
-    mpf_versions_dict = get_or_read_json(mpf_versions_json_path)
+    mpf_versions_dict = read_json(mpf_versions_json_path)
+
     mpf_versions_dict = mpf_versions_dict["versions"]
 
-    mpf_checksums_dict = get_or_read_json(mpf_checkfiles_json_path)
+    mpf_checksums_dict = read_json(mpf_checkfiles_json_path)
     mpf_checksums_dict = mpf_checksums_dict["checksums"]
 
-    mpf_files_dict = get_or_read_json(mpf_files_json_path)
+    mpf_files_dict = read_json(mpf_files_json_path)
     mpf_files_dict = mpf_files_dict["files"]
 
     return mpf_versions_dict, mpf_checksums_dict, mpf_files_dict

cfbs/commands.py

@@ -14,6 +14,7 @@
 from cfbs.args import get_args
 
 from cfbs.utils import (
+    FetchError,
     cfbs_dir,
     cfbs_filename,
     is_cfbs_repo,
@@ -905,7 +906,12 @@ def _download_dependencies(
                 sh("git clone %s %s" % (url, commit_dir))
                 sh("(cd %s && git checkout %s)" % (commit_dir, commit))
             else:
-                versions = get_json(_VERSION_INDEX)
+                try:
+                    versions = get_json(_VERSION_INDEX)
+                except FetchError as e:
+                    user_error(
+                        "Downloading CFEngine Build Module Index failed - check your Wi-Fi / network settings."
+                    )
                 try:
                     checksum = versions[name][module["version"]]["archive_sha256"]
                 except KeyError:

cfbs/index.py

@@ -2,7 +2,7 @@
 from collections import OrderedDict
 
 from cfbs.module import Module
-from cfbs.utils import get_or_read_json, user_error, get_json
+from cfbs.utils import FetchError, get_or_read_json, user_error, get_json
 from cfbs.internal_file_management import local_module_name
 
 _DEFAULT_INDEX = (
@@ -87,7 +87,13 @@ def _expand_index(self):
 
         assert type(index) is str
 
-        self._data = get_or_read_json(index)
+        try:
+            self._data = get_or_read_json(index)
+        except FetchError as e:
+            user_error(
+                "Downloading index '%s' failed - check your Wi-Fi / network settings."
+                % index
+            )
 
         if not self._data:
             sys.exit("Could not download or find module index")
@@ -121,7 +127,13 @@ def exists(self, module):
             return True
         if not version:
             return name in self
-        versions = get_json(_VERSION_INDEX)
+        try:
+            versions = get_json(_VERSION_INDEX)
+        except FetchError as e:
+            user_error(
+                "Downloading CFEngine Build Module Index failed - check your Wi-Fi / network settings."
+            )
+
         return name in versions and version in versions[name]
 
     def check_existence(self, modules: list):
@@ -162,7 +174,12 @@ def get_module_object(self, module, added_by=None):
         else:
             object = self[name]
             if version:
-                versions = get_json(_VERSION_INDEX)
+                try:
+                    versions = get_json(_VERSION_INDEX)
+                except FetchError as e:
+                    user_error(
+                        "Downloading CFEngine Build Module Index failed - check your Wi-Fi / network settings."
+                    )
                 new_values = versions[name][version]
                 specifics = {
                     k: v for (k, v) in new_values.items() if k in Module.attributes()

cfbs/masterfiles/download_all_versions.py

@@ -13,7 +13,12 @@ def get_download_urls_enterprise(min_version=None):
 
     print("* gathering download URLs...")
 
-    data = get_json(ENTERPRISE_RELEASES_URL)
+    try:
+        data = get_json(ENTERPRISE_RELEASES_URL)
+    except FetchError as e:
+        user_error(
+            "Downloading CFEngine release data failed - check your Wi-Fi / network settings."
+        )
 
     for release_data in data["releases"]:
         version = release_data["version"]
@@ -38,7 +43,13 @@ def get_download_urls_enterprise(min_version=None):
             continue
 
         release_url = release_data["URL"]
-        subdata = get_json(release_url)
+        try:
+            subdata = get_json(release_url)
+        except FetchError as e:
+            user_error(
+                "Downloading CFEngine release data for version %s failed - check your Wi-Fi / network settings."
+                % version
+            )
         artifacts_data = subdata["artifacts"]
 
         if "Additional Assets" not in artifacts_data:

cfbs/utils.py

@@ -115,9 +115,12 @@ def user_error(msg: str):
 
 
 def get_json(url: str) -> OrderedDict:
-    with urllib.request.urlopen(url) as r:
-        assert r.status >= 200 and r.status < 300
-        return json.loads(r.read().decode(), object_pairs_hook=OrderedDict)
+    try:
+        with urllib.request.urlopen(url) as r:
+            assert r.status >= 200 and r.status < 300
+            return json.loads(r.read().decode(), object_pairs_hook=OrderedDict)
+    except urllib.error.URLError as e:
+        raise FetchError("Failed to get JSON from '%s'" % url) from e
 
 
 def get_or_read_json(path: str) -> OrderedDict: