fix(pip/_internal): Add a generic network exception to be raised

Author: gutsytechster

news/5380.bugfix

@@ -0,0 +1 @@
+Raise user friendly errors on network failures

src/pip/_internal/cli/base_command.py

@@ -27,6 +27,7 @@
     BadCommand,
     CommandError,
     InstallationError,
+    NetworkConnectionError,
     PreviousBuildDirError,
     SubProcessError,
     UninstallationError,
@@ -203,7 +204,7 @@ def _main(self, args):
 
             return PREVIOUS_BUILD_DIR_ERROR
         except (InstallationError, UninstallationError, BadCommand,
-                SubProcessError) as exc:
+                SubProcessError, NetworkConnectionError) as exc:
             logger.critical(str(exc))
             logger.debug('Exception information:', exc_info=True)
 

src/pip/_internal/exceptions.py

@@ -93,6 +93,10 @@ class PreviousBuildDirError(PipError):
     """Raised when there's a previous conflicting build directory"""
 
 
+class NetworkConnectionError(PipError):
+    """HTTP connection error"""
+
+
 class InvalidWheelFilename(InstallationError):
     """Invalid wheel filename."""
 

src/pip/_internal/network/utils.py

@@ -1,5 +1,7 @@
 from pip._vendor.requests.models import CONTENT_CHUNK_SIZE, Response
+from pip._vendor.urllib3.exceptions import NewConnectionError, ReadTimeoutError
 
+from pip._internal.exceptions import NetworkConnectionError
 from pip._internal.utils.typing import MYPY_CHECK_RUNNING
 
 if MYPY_CHECK_RUNNING:
@@ -46,3 +48,8 @@ def response_chunks(response, chunk_size=CONTENT_CHUNK_SIZE):
             if not chunk:
                 break
             yield chunk
+    except (NewConnectionError, ReadTimeoutError) as exc:
+        raise NetworkConnectionError(
+            "Failed to get address for host! Check your network connectivity "
+            "and DNS settings.\nDetails: {}".format(exc)
+        )