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author | Ghe Rivero <ghe@debian.org> | 2013-06-26 08:22:47 +0200 |
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committer | Ghe Rivero <ghe@debian.org> | 2013-06-26 08:24:26 +0200 |
commit | f1304462319ff148c722bea57098c76a803dc4cc (patch) | |
tree | c76a4169749dbc349554e1aa0a2e503431566053 /ironic/openstack | |
parent | 0f586b4e09368f16a3374563e2d4374b578c41b2 (diff) | |
download | ironic-f1304462319ff148c722bea57098c76a803dc4cc.tar.gz |
Sync fileutils from oslo-incubator
Implements: blueprint equivalent-pxe-driver
Change-Id: I2e3ea3e5cf0012a5eb8c75d8aabba0efd9f47257
Diffstat (limited to 'ironic/openstack')
-rw-r--r-- | ironic/openstack/common/fileutils.py | 75 |
1 files changed, 75 insertions, 0 deletions
diff --git a/ironic/openstack/common/fileutils.py b/ironic/openstack/common/fileutils.py index b988ad03d..d643bd257 100644 --- a/ironic/openstack/common/fileutils.py +++ b/ironic/openstack/common/fileutils.py @@ -16,9 +16,18 @@ # under the License. +import contextlib import errno import os +from ironic.openstack.common import excutils +from ironic.openstack.common.gettextutils import _ +from ironic.openstack.common import log as logging + +LOG = logging.getLogger(__name__) + +_FILE_CACHE = {} + def ensure_tree(path): """Create a directory (and any ancestor directories required) @@ -33,3 +42,69 @@ def ensure_tree(path): raise else: raise + + +def read_cached_file(filename, force_reload=False): + """Read from a file if it has been modified. + + :param force_reload: Whether to reload the file. + :returns: A tuple with a boolean specifying if the data is fresh + or not. + """ + global _FILE_CACHE + + if force_reload and filename in _FILE_CACHE: + del _FILE_CACHE[filename] + + reloaded = False + mtime = os.path.getmtime(filename) + cache_info = _FILE_CACHE.setdefault(filename, {}) + + if not cache_info or mtime > cache_info.get('mtime', 0): + LOG.debug(_("Reloading cached file %s") % filename) + with open(filename) as fap: + cache_info['data'] = fap.read() + cache_info['mtime'] = mtime + reloaded = True + return (reloaded, cache_info['data']) + + +def delete_if_exists(path): + """Delete a file, but ignore file not found error. + + :param path: File to delete + """ + + try: + os.unlink(path) + except OSError as e: + if e.errno == errno.ENOENT: + return + else: + raise + + +@contextlib.contextmanager +def remove_path_on_error(path): + """Protect code that wants to operate on PATH atomically. + Any exception will cause PATH to be removed. + + :param path: File to work with + """ + try: + yield + except Exception: + with excutils.save_and_reraise_exception(): + delete_if_exists(path) + + +def file_open(*args, **kwargs): + """Open file + + see built-in file() documentation for more details + + Note: The reason this is kept in a separate module is to easily + be able to provide a stub module that doesn't alter system + state at all (for unit tests) + """ + return file(*args, **kwargs) |