X-Git-Url: http://xvm.mit.edu/gitweb/invirt/packages/invirt-base.git/blobdiff_plain/2c05818e4e51df1dde27db1f25b0eb493bc8be6f..f2acfa0565a11ed251ad390461a5c428640681c2:/files/usr/share/python-support/sipb-xen-base/invirt/config.py

diff --git a/files/usr/share/python-support/sipb-xen-base/invirt/config.py b/files/usr/share/python-support/sipb-xen-base/invirt/config.py
deleted file mode 100644
index cead926..0000000
--- a/files/usr/share/python-support/sipb-xen-base/invirt/config.py
+++ /dev/null
@@ -1,86 +0,0 @@
-import json
-from invirt.common import *
-from os.path import getmtime
-
-default_src_path   = '/etc/invirt/master.yaml'
-default_cache_path = '/var/lib/invirt/cache.json'
-lock_file          = '/var/lib/invirt/cache.lock'
-
-def load(src_path = default_src_path,
-         cache_path = default_cache_path,
-         force_refresh = False):
-    """
-    Try loading the configuration from the faster-to-load JSON cache at
-    cache_path.  If it doesn't exist or is outdated, load the configuration
-    instead from the original YAML file at src_path and regenerate the cache.
-    I assume I have the permissions to write to the cache directory.
-    """
-
-    # Namespace container for state variables, so that they can be updated by
-    # closures.
-    ns = struct()
-
-    if force_refresh:
-        do_refresh = True
-    else:
-        src_mtime = getmtime(src_path)
-        try:            cache_mtime = getmtime(cache_path)
-        except OSError: do_refresh  = True
-        else:           do_refresh  = src_mtime + 1 >= cache_mtime
-
-        # We chose not to simply say
-        #
-        #   do_refresh = src_mtime >= cache_time
-        #
-        # because between the getmtime(src_path) and the time the cache is
-        # rewritten, the master configuration may have been updated, so future
-        # checks here would find a cache with a newer mtime than the master
-        # (and thus treat the cache as containing the latest version of the
-        # master).  The +1 means that for at least a full second following the
-        # update to the master, this function will refresh the cache, giving us
-        # 1 second to write the cache.  Note that if it takes longer than 1
-        # second to write the cache, then this situation could still arise.
-        #
-        # The getmtime calls should logically be part of the same transaction
-        # as the rest of this function (cache read + conditional cache
-        # refresh), but to wrap everything in an flock would cause the
-        # following cache read to be less streamlined.
-
-    if not do_refresh:
-        # Try reading from the cache first.  This must be transactionally
-        # isolated from concurrent writes to prevent reading an incomplete
-        # (changing) version of the data (but the transaction can share the
-        # lock with other concurrent reads).  This isolation is accomplished
-        # using an atomic filesystem rename in the refreshing stage.
-        try: ns.cfg = with_closing(file(cache_path)) (
-                lambda f: json.read(f.read()))
-        except: do_refresh = True
-
-    if do_refresh:
-        # Atomically reload the source and regenerate the cache.  The read and
-        # write must be a single transaction, or a stale version may be
-        # written (if another read/write of a more recent configuration
-        # is interleaved).  The final atomic rename is to keep this
-        # transactionally isolated from the above cache read.  If we fail to
-        # acquire the lock, just try to load the master configuration.
-        import yaml
-        try:    loader = yaml.CSafeLoader
-        except: loader = yaml.SafeLoader
-        try:
-            @with_lock_file(lock_file)
-            def refresh_cache():
-                ns.cfg = with_closing(file(src_path)) (
-                        lambda f: yaml.load(f, loader))
-                try: with_closing(file(cache_path + '.tmp', 'w')) (
-                        lambda f: f.write(json.write(ns.cfg)))
-                except: pass # silent failure
-                else: os.rename(cache_path + '.tmp', cache_path)
-        except IOError:
-            ns.cfg = with_closing(file(src_path)) (
-                    lambda f: yaml.load(f, loader))
-    return ns.cfg
-
-dicts = load()
-structs = dicts2struct(dicts)
-
-# vim:et:sw=4:ts=4