api: check git name and email is configuration

(closes #216)

renku/api/repository.py

@@ -164,6 +164,10 @@ def init_repository(
 
         self.git.description = name or path.name
 
+        # Check that an author can be determined from Git.
+        from renku.models.datasets import Author
+        Author.from_git(self.git)
+
         # TODO read existing gitignore and create a unique set of rules
         import pkg_resources
         gitignore_default = pkg_resources.resource_stream(

renku/errors.py

@@ -82,6 +82,32 @@ class ConfigurationError(RenkuException, click.ClickException):
     """Raise in case of misconfiguration."""
 
 
+class MissingUsername(ConfigurationError):
+    """Raise when the username is not configured."""
+
+    def __init__(self, message=None):
+        """Build a custom message."""
+        message = message or (
+            'The user name is not configured. '
+            'Please use the "git config" command to configure it.\n\n'
+            '\tgit config --set user.name "John Doe"\n'
+        )
+        super(MissingUsername, self).__init__(message)
+
+
+class MissingEmail(ConfigurationError):
+    """Raise when the email is not configured."""
+
+    def __init__(self, message=None):
+        """Build a custom message."""
+        message = message or (
+            'The email address is not configured. '
+            'Please use the "git config" command to configure it.\n\n'
+            '\tgit config --set user.email "john.doe@example.com"\n'
+        )
+        super(MissingUsername, self).__init__(message)
+
+
 class AuthenticationError(RenkuException, click.ClickException):
     """Raise when there is a problem with authentication."""
 

renku/models/datasets.py

@@ -17,6 +17,7 @@
 # limitations under the License.
 """Model objects representing datasets."""
 
+import configparser
 import datetime
 import re
 import uuid
@@ -26,6 +27,7 @@
 from attr.validators import instance_of
 from dateutil.parser import parse as parse_date
 
+from renku import errors
 from renku._compat import Path
 
 from . import _jsonld as jsonld
@@ -84,10 +86,24 @@ def check_email(self, attribute, value):
     def from_git(cls, git):
         """Create an instance from a Git repo."""
         git_config = git.config_reader()
-        return cls(
-            name=git_config.get('user', 'name'),
-            email=git_config.get('user', 'email'),
-        )
+        try:
+            name = git_config.get_value('user', 'name', None)
+            email = git_config.get_value('user', 'email', None)
+        except configparser.NoOptionError:  # pragma: no cover
+            raise errors.ConfigurationError(
+                'The user name and email are not configured. '
+                'Please use the "git config" command to configure them.\n\n'
+                '\tgit config --set user.name "John Doe"\n'
+                '\tgit config --set user.email "john.doe@example.com"\n'
+            )
+
+        # Check the git configuration.
+        if name is None:  # pragma: no cover
+            raise errors.MissingUsername()
+        if email is None:  # pragma: no cover
+            raise errors.MissingEmail()
+
+        return cls(name=name, email=email)
 
     @classmethod
     def from_commit(cls, commit):