Merge lp:~javier.collado/utah/bug1023013 into lp:utah

[Javier Collado]

Added URL checker to run_utah_tests.py, so that it can fail early when the URL for a runlist doesn't exist.

The code that implements the URL check might be useful in some other part of the code and could be moved to a library. Let me know if that's the case or just let's move it if needed in the future.

[lp:~javier.collado/utah/bug1023013]

375. By Javier Collado on 2012-07-11

Moved URLChecker code to utah.url module

[Max Brustkern (nuclearbob)]

Good stuff. At some point utah/provisioning/provisioning.py should use this function as well.

review: Approve

=== modified file 'examples/run_utah_tests.py'
--- examples/run_utah_tests.py	2012-07-05 14:48:39 +0000
+++ examples/run_utah_tests.py	2012-07-11 13:46:21 +0000
@@ -10,6 +10,7 @@
 import urllib
 
 from utah import UTAHException
+from utah.url import URLChecker
 import utah.provisioning
 from run_test_vm import run_test_vm
 
@@ -63,6 +64,12 @@
         sys.stderr.write("Please check the roadmap, as it will be included in a future version.\n")
         sys.exit(4)
 
+    url_checker = URLChecker()
+    for runlist in args.runlists:
+        if not url_checker.open(runlist):
+            sys.stderr.write("Run list not found: " + runlist + "\n")
+            sys.exit(5)
+
     function = run_test_vm
 
     for option in [args.boot, args.emulator, args.image, args.initrd, args.kernel, args.preseed, args.xml]:

=== added file 'utah/url.py'
--- utah/url.py	1970-01-01 00:00:00 +0000
+++ utah/url.py	2012-07-11 13:46:21 +0000
@@ -0,0 +1,48 @@
+"""
+URL tools
+"""
+import os
+import urllib
+import urllib2
+
+
+# Inspired by: http://stackoverflow.com/a/2070916/183066
+class HeadRequest(urllib2.Request):
+    """
+    Request that sends HEAD method instead of GET
+    """
+    def get_method(self):
+        return 'HEAD'
+
+
+class URLChecker(urllib.URLopener):
+    """
+    Check that URL exists withou opening it
+    or downloading its contents
+    """
+    def open_http(self, url, data=None):
+        """
+        Check if http URL exists
+        """
+        # This is redundant becuase urllib2 will call urllib
+        # under the hood, but makes code easy to read.
+        # Note that in the case of a redirect,
+        # a GET request will be sent instead of a HEAD one
+        # since that's how the urllib2.HTTPRedirectHandler
+        # implementation works
+        try:
+            response = urllib2.urlopen(HeadRequest('http:' + url))
+        except urllib2.URLError:
+            return False
+
+        return response.getcode() == 200
+
+    def open_local_file(self, url):
+        """
+        Check if local file exists
+        """
+        # Based on urllib.URLopener.open_local_file implementation
+        host, filename = urllib.splithost(url)
+        path = urllib.url2pathname(filename)
+
+        return os.path.exists(path)