=== modified file 'doc/changes.rst'
--- doc/changes.rst	2012-05-06 16:01:25 +0000
+++ doc/changes.rst	2012-05-09 07:16:32 +0000
@@ -7,6 +7,7 @@
 =========================================
 
 * Use squid proxy for caching mechanism
+* Merge revert-cache-tarball
 
 .. _version_0_6:
 

=== modified file 'lava_dispatcher/client/master.py'
--- lava_dispatcher/client/master.py	2012-05-08 18:35:36 +0000
+++ lava_dispatcher/client/master.py	2012-05-09 07:16:32 +0000
@@ -35,9 +35,11 @@
 
 from lava_dispatcher.utils import (
     download,
+    download_with_cache,
     logging_spawn,
     logging_system,
-    string_to_list)
+    string_to_list,
+    url_to_cache, link_or_copy_file)
 from lava_dispatcher.client.base import (
     CommandRunner,
     CriticalError,
@@ -293,12 +295,82 @@
                 return uncompressed_name
         return image_file
 
+    def _tarball_url_to_cache(self, url, cachedir):
+        cache_loc = url_to_cache(url, cachedir)
+        # can't have a folder name same as file name. replacing '.' with '.'
+        return os.path.join(cache_loc.replace('.','-'), "tarballs")
+
+    def _are_tarballs_cached(self, image, lava_cachedir):
+        cache_loc = self._tarball_url_to_cache(image, lava_cachedir)
+        cached = os.path.exists(os.path.join(cache_loc, "boot.tgz")) and \
+               os.path.exists(os.path.join(cache_loc, "root.tgz"))
+
+        if cached:
+            return True;
+
+        # Check if there is an other lava-dispatch instance have start to cache the same image
+        # see the _about_to_cache_tarballs
+        if not os.path.exists(os.path.join(cache_loc, "tarballs-cache-ongoing")):
+            return False
+
+        # wait x minute for caching is done.
+        waittime=20
+
+        logging.info("Waiting for the other instance of lava-dispatcher to finish the caching of %s", image)
+        while waittime > 0:
+            if not os.path.exists(os.path.join(cache_loc, "tarballs-cache-ongoing")):
+                waittime = 0
+            else:
+                time.sleep(60)
+                waittime = waittime - 1
+                if (waittime % 5) == 0:
+                    logging.info("%d minute left..." % waittime)
+
+        return os.path.exists(os.path.join(cache_loc, "boot.tgz")) and \
+               os.path.exists(os.path.join(cache_loc, "root.tgz"))
+
+    def _get_cached_tarballs(self, image, tarball_dir, lava_cachedir):
+        cache_loc = self._tarball_url_to_cache(image, lava_cachedir)
+
+        boot_tgz = os.path.join(tarball_dir,"boot.tgz")
+        root_tgz = os.path.join(tarball_dir,"root.tgz")
+        link_or_copy_file(os.path.join(cache_loc, "root.tgz"), root_tgz)
+        link_or_copy_file(os.path.join(cache_loc, "boot.tgz"), boot_tgz)
+
+        return (boot_tgz,root_tgz)
+
+    def _about_to_cache_tarballs(self, image, lava_cachedir):
+        # create this folder to indicate this instance of lava-dispatcher is caching this image.
+        # see _are_tarballs_cached
+        # return false if unable to create the directory. The caller should not cache the tarballs
+        cache_loc = self._tarball_url_to_cache(image, lava_cachedir)
+        path = os.path.join(cache_loc, "tarballs-cache-ongoing")
+        try:
+          os.makedirs(path)
+        except OSError as exc: # Python >2.5
+            if exc.errno == errno.EEXIST:
+                # other dispatcher process already caching - concurrency issue
+                return False
+            else:
+                raise
+        return True
+
+    def _cache_tarballs(self, image, boot_tgz, root_tgz, lava_cachedir):
+        cache_loc = self._tarball_url_to_cache(image, lava_cachedir)
+        if not os.path.exists(cache_loc):
+              os.makedirs(cache_loc)
+        c_boot_tgz = os.path.join(cache_loc, "boot.tgz")
+        c_root_tgz = os.path.join(cache_loc, "root.tgz")
+        shutil.copy(boot_tgz, c_boot_tgz)
+        shutil.copy(root_tgz, c_root_tgz)
+        path = os.path.join(cache_loc, "tarballs-cache-ongoing")
+        if os.path.exists(path):
+            shutil.rmtree(path)
+
     def deploy_linaro(self, hwpack=None, rootfs=None, image=None,
                       kernel_matrix=None, use_cache=True, rootfstype='ext3'):
         LAVA_IMAGE_TMPDIR = self.context.lava_image_tmpdir
         LAVA_IMAGE_URL = self.context.lava_image_url
-        lava_proxy = self.context.lava_proxy
-
         # validate in parameters
         if image is None:
             if hwpack is None or rootfs is None:
@@ -317,10 +389,35 @@
             else:
                 tarball_dir = mkdtemp(dir=LAVA_IMAGE_TMPDIR)
                 os.chmod(tarball_dir, 0755)
-                proxy = lava_proxy if use_cache else None
-                image_file = download(image, tarball_dir, proxy)
-                image_file = self.decompress(image_file)
-                boot_tgz, root_tgz = self._generate_tarballs(image_file)
+                if use_cache:
+                    lava_cachedir = self.context.lava_cachedir
+                    if self._are_tarballs_cached(image, lava_cachedir):
+                        logging.info("Reusing cached tarballs")
+                        boot_tgz, root_tgz = self._get_cached_tarballs(image, tarball_dir, lava_cachedir)
+                    else:
+                        logging.info("Downloading and caching the tarballs")
+                        # in some corner case, there can be more than one lava-dispatchers execute
+                        # caching of same tarballs exact at the same time. One of them will successfully
+                        # get the lock directory. The rest will skip the caching if _about_to_cache_tarballs
+                        # return false.
+                        should_cache = self._about_to_cache_tarballs(image, lava_cachedir)
+                        image_file = download_with_cache(image, tarball_dir, lava_cachedir)
+                        image_file = self.decompress(image_file)
+                        boot_tgz, root_tgz = self._generate_tarballs(image_file)
+                        if should_cache:
+                            self._cache_tarballs(image, boot_tgz, root_tgz, lava_cachedir)
+                else:
+                    lava_proxy = self.context.lava_proxy
+                    image_file = download(image, tarball_dir, lava_proxy)
+                    image_file = self.decompress(image_file)
+                    boot_tgz, root_tgz = self._generate_tarballs(image_file)
+                    # remove the cached tarballs
+                    cache_loc = self._tarball_url_to_cache(image, lava_cachedir)
+                    shutil.rmtree(cache_loc, ignore_errors = true)
+                    # remove the cached image files
+                    cache_loc = url_to_cache
+                    shutil.rmtree(cache_loc, ignore_errors = true)
+
         except CriticalError:
             raise
         except:
@@ -441,6 +538,7 @@
         logging.info("Downloading the image files")
 
         proxy = lava_proxy if use_cache else None
+        
         boot_path = download(boot_url, tarball_dir, proxy)
         system_path = download(system_url, tarball_dir, proxy)
         data_path = download(data_url, tarball_dir, proxy)

=== modified file 'lava_dispatcher/context.py'
--- lava_dispatcher/context.py	2012-05-07 03:46:16 +0000
+++ lava_dispatcher/context.py	2012-05-08 05:37:59 +0000
@@ -84,3 +84,7 @@
     @property
     def lava_result_dir(self):
         return self.config.get("LAVA_RESULT_DIR")
+
+    @property
+    def lava_cachedir(self):
+        return self.config.get("LAVA_CACHEDIR")

=== modified file 'lava_dispatcher/default-config/lava-dispatcher/lava-dispatcher.conf'
--- lava_dispatcher/default-config/lava-dispatcher/lava-dispatcher.conf	2012-05-07 03:46:16 +0000
+++ lava_dispatcher/default-config/lava-dispatcher/lava-dispatcher.conf	2012-05-08 05:37:59 +0000
@@ -18,6 +18,9 @@
 # Location on the device for storing test results.
 LAVA_RESULT_DIR = /lava/results
 
+# Location for caching downloaded artifacts such as hwpacks and images
+LAVA_CACHEDIR = /linaro/images/cache
+
 # Python logging level to use
 # 10 = DEBUG
 # 20 = INFO

=== modified file 'lava_dispatcher/utils.py'
--- lava_dispatcher/utils.py	2012-05-06 15:58:03 +0000
+++ lava_dispatcher/utils.py	2012-05-08 05:56:59 +0000
@@ -53,9 +53,46 @@
         raise RuntimeError("Could not retrieve %s" % url)
     return filename
 
+def link_or_copy_file(src, dest):
+    try:
+        dir = os.path.dirname(dest)
+        if not os.path.exists(dir):
+            os.makedirs(dir)
+        os.link(src, dest)
+    except OSError, err:
+        if err.errno == errno.EXDEV:
+            shutil.copy(src, dest)
+        if err.errno == errno.EEXIST:
+            logging.debug("Cached copy of %s already exists" % dest)
+        else:
+            logging.exception("os.link '%s' with '%s' failed" % (src, dest))
+
+def copy_file(src, dest):
+    dir = os.path.dirname(dest)
+    if not os.path.exists(dir):
+        os.makedirs(dir)
+    shutil.copy(src, dest)
+
+
 # XXX: duplication, we have similar code in lava-test, we need to move that to
 # lava.utils -> namespace as standalone package
-# def download_with_cache(url, path="", cachedir=""):
+def download_with_cache(url, path="", cachedir=""):
+    cache_loc = url_to_cache(url, cachedir)
+    if os.path.exists(cache_loc):
+        filename = os.path.basename(cache_loc)
+        file_location = os.path.join(path, filename)
+        link_or_copy_file(cache_loc, file_location)
+    else:
+        file_location = download(url, path)
+        copy_file(file_location, cache_loc)
+    return file_location
+
+
+def url_to_cache(url, cachedir):
+    url_parts = urlparse.urlsplit(url)
+    path = os.path.join(cachedir, url_parts.netloc,
+        url_parts.path.lstrip(os.sep))
+    return path
 
 
 def string_to_list(string):

