Add runtime requirements checker

1 files changed, 101 insertions, 0 deletions

diff --git a/src/leap/util/requirement_checker.py b/src/leap/util/requirement_checker.py
new file mode 100644
index 00000000..3538f122
--- /dev/null
+++ b/src/leap/util/requirement_checker.py
@@ -0,0 +1,101 @@
+# -*- coding: utf-8 -*-
+# requirement_checker.py
+# Copyright (C) 2013 LEAP
+#
+# This program is free software: you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+"""
+Utility to check the needed requirements.
+"""
+
+import os
+import logging
+
+from pkg_resources import (DistributionNotFound,
+                           get_distribution,
+                           Requirement,
+                           resource_stream,
+                           VersionConflict)
+
+logger = logging.getLogger(__name__)
+
+
+def get_requirements():
+    """
+    This function returns a list with requirements.
+    It checks either if its running from the source or if its installed.
+
+    :returns: a list with packages names, required for the app.
+    :return type: list of str.
+    """
+    develop = True
+    requirements = []
+
+    try:
+        # if we are running from the source
+        from pkg import util
+        requirements = util.parse_requirements()
+    except ImportError:
+        develop = False
+
+    # if we are running from the package
+    if not develop:
+        requires_file_name = os.path.join('leap', 'util', 'reqs.txt')
+        dist_name = Requirement.parse('leap-client')
+
+        try:
+            with resource_stream(dist_name, requires_file_name) as stream:
+                requirements = [line.strip() for line in stream]
+        except Exception, e:
+            logger.error("Requirements file not found. %e", (e, ))
+
+    return requirements
+
+
+def check_requirements():
+    """
+    This function check the dependencies declared in the
+    requirement(s) file(s) and logs the results.
+    """
+    logger.debug("Checking requirements...")
+    requirements = get_requirements()
+
+    for package in requirements:
+        try:
+            get_distribution(package)
+        except VersionConflict:
+            required_package = Requirement.parse(package)
+            required_version = required_package.specs[0]
+            required_name = required_package.key
+
+            installed_package = get_distribution(required_name)
+            installed_version = installed_package.version
+            installed_location = installed_package.location
+
+            msg = "Error: version not satisfied. "
+            msg += "Expected %s, installed %s (path: %s)." % (
+                required_version, installed_version, installed_location)
+
+            result = "%s ... %s" % (package, msg)
+            logger.error(result)
+        except DistributionNotFound:
+            msg = "Error: package not found!"
+            result = "%s ... %s" % (package, msg)
+            logger.error(result)
+        else:
+            msg = "OK"
+            result = "%s ... %s" % (package, msg)
+            logger.debug(result)
+
+    logger.debug('Done')