# Copyright 2020 AUI, Inc. Washington DC, USA
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
"""
this module will be included in the api
"""
[docs]def measures_update(path=None, version=None, force=False, logger=None, auto_update_rules=False, use_astron_obs_table=False, verbose=None):
"""
Update or install the IERS data used for measures calculations from ASTRON into path.
Original data source used by ASTRON is here: https://www.iers.org/IERS/EN/DataProducts/data.html
If no update is necessary then this function will silently return.
The verbose argument controls the level of information provided by this function when the data
are unchanged for expected reasons. A level of 0 outputs nothing. A
value of 1 sends any output to the logger and a value of 2 logs and prints the information.
The default value of the verbose argument is taken from the casaconfig_verbose config
value (defaults to 1).
CASA maintains a separate Observatories table which is available in the casarundata
collection through pull_data and data_update. The Observatories table found at ASTRON
is not installed by measures_update and any Observatories file at path will not be changed
by using this function. This behavior can be changed by setting force and use_astron_obs_table
both to True (use_astron_obs_table is ignored when force is False).
A text file (readme.txt in the geodetic directory in path) records the measures version string
and the date when that version was installed in path.
If path is None then config.measurespath is used.
If the version requested matches the one in that text file then this function does
nothing unless force is True.
If a specific version is not requested (the default) and the modification time of that text
file is less than 24 hrs before now then this function does nothing unless force is True. When this
function checks for a more recent version and finds that the installed version is the most recent
then the modification time of that text file is changed to the current time even though nothing has
changed in path. This limits the number of attempts to update the measures data (including checking
for more recent data) to once per day. When the force argument is True and a specific version is
not requested then this function always checks for the latest version.
When auto_update_rules is True then path must exist and contain the expected readme.txt file.
Path must be owned by the user, force must be False, and the version must be None. This
option is used during casatools initialization when measures_auto_update is True. Automatic
updating happens during casatools initialization so that the updated measures are in place
before any tool needs to use them.
Using measures_update after casatools has started should always be followed by exiting
and restarting casa (or the casatools module if modular casa components are being used).
A file lock is used to prevent more that one data update (pull_data, measures_update,
or data_update) from updating any files in path at the same time. When locked, the
lock file (data_update.lock in path) contains information about the process that
has the lock. When measures_update gets the lock it checks the readme.txt file in path
to make sure that an update is still necessary (if force is True then an update
always happens). If the lock file is not empty then a previous update of path (pull_data,
data_update, or measures_update) did not exit as expected and the contents of path are
suspect. In that case, an error will be reported and nothing will be updated. The lock
file can be checked to see the details of when that file was locked. The lock file can be
removed and measures_update can be tried again. It may be safest in that case to remove path
completely or use a different path and use pull_data to install a fresh copy of the
desired version.
Care should be used when using measures_update outside of the normal automatic
update that other casa sessions are not using the same measures at the same time,
especially if they may also be starting at that time. If a specific version is
requested or force is True there is a risk that the measures may be updated while
one of those other sessions are trying to load the same measures data, leading to
unpredictable results. The lock file will prevent simultaneous updates from
happening but if each simultaneous update eventually updates the same measures
location (because force is True or the updates are requesting different versions)
then the measures that any of those simultaneous casatools modules sees is
unpredictable. Avoid multiple, simultaneous updates outside of the automatic
update process.
**Note:** during auto updates, measures_update requires that the expected
readme.txt file already exists in the geodetic directory at path. If that file does
not exist or can not be interpreted as expected then measures_update will
return without updating any data.
**Note:** if auto_update_rules is True the user must own path (in addition to having
read and write permissions there). The version must then also be None and the force option
must be False.
**Note:** During use outside of auto updates, if path does not exist it will be created
by this function.
**Note:** During use outside of auto updates, if the readme.txt file exists but can not
be read as expected **OR** that file does not exist but the contents of path appear to
contain measures data (table names in the expected locations) then this function will
print messages describing that and exit without changing anything at path. Using
a force value of True will disable this check and install measures at path even if path
is not empty or the readme.txt file can not be read. This use of force should be used
with caution.
Parameters
- path (str=None) - Folder path to place updated measures data. Must contain a valid geodetic/readme.txt. If not set then config.measurespath is used.
- version (str=None) - Version of measures data to retrieve (usually in the form of WSRT_Measures_yyyymmdd-160001.ztar, see measures_available()). Default None retrieves the latest.
- force (bool=False) - If True, always re-download the measures data. Default False will not download measures data if updated within the past day unless the version parameter is specified and different from what was last downloaded.
- logger (casatools.logsink=None) - Instance of the casalogger to use for writing messages. Default None writes messages to the terminal
- auto_update_rules (bool=False) - If True then the user must be the owner of path, version must be None, and force must be False.
- use_astron_obs_table (bool=False) - If True and force is also True then keep the Observatories table found in the Measures tar tarball (possibly overwriting the Observatories table from casarundata).
- verbose (int=None) - Level of output, 0 is none, 1 is to logger, 2 is to logger and terminal, defaults to casaconfig_verbose in config dictionary.
Returns
None
Raises
- casaconfig.AutoUpdatesNotAllowed - raised when path does not exists as a directory or is not owned by the user when auto_update_rules is True
- casaconfig.BadLock - raised when the lock file was not empty when found
- casaconfig.BadReadme - raised when something unexpected is found in the readme or the readme changed after an update is in progress
- casaconfig.NoReadme - raised when the readme.txt file is not found at path (path also may not exist)
- casaconfig.NotWritable - raised when the user does not have permission to write to path
- casaconfig.RemoteError - raised by measures_available when the remote list of measures could not be fetched
- casaconfig.UnsetMeasurespath - raised when path is None and has not been set in config
- Exception - raised when something unexpected happened while updating measures
"""
import os
import pkg_resources
from datetime import datetime
import sys
import tarfile
import re
import ssl
import urllib.request
import certifi
import shutil
from casaconfig import measures_available
from casaconfig import AutoUpdatesNotAllowed, UnsetMeasurespath, RemoteError, NotWritable, BadReadme, BadLock, NoReadme
from .print_log_messages import print_log_messages
from .get_data_lock import get_data_lock
from .get_data_info import get_data_info
from .measures_available import measures_available
if path is None:
from .. import config as _config
path = _config.measurespath
if path is None:
raise UnsetMeasurespath('measures_update: path is None and has not been set in config.measurespath. Provide a valid path and retry.')
if verbose is None:
from .. import config as _config
verbose = _config.casaconfig_verbose
path = os.path.expanduser(path)
if auto_update_rules:
if version is not None:
print_log_messages('auto_update_rules requires that version be None', logger, True)
return
if force:
print_log_messages('force must be False when auto_update_rules is True', logger, True)
return
if (not os.path.isdir(path)) or (os.stat(path).st_uid != os.getuid()):
raise AutoUpdatesNotAllowed("measures_update: path must exist as a directory and it must be owned by the user, path = %s" % path)
if not os.path.exists(path):
# make dirs all the way down, if possible
os.makedirs(path)
current = None
ageRecent = False
# first, does this look like it needs to be updated
# get any existing measures readme information
readmeInfo = get_data_info(path, logger, type='measures')
if readmeInfo is not None:
current = readmeInfo['version']
if readmeInfo['age'] is not None:
ageRecent = readmeInfo['age'] < 1.0
if not force:
# don't check for new version if the age is less than 1 day
if version is None and ageRecent:
if verbose > 0:
print_log_messages('measures_update: version installed or checked less than 1 day ago, nothing updated or checked', logger, verbose=verbose)
return
# don't overwrite something that looks bad unless forced to do so
if current == 'invalid':
raise NoReadme('measures_update: no measures readme.txt file found at %s. Nothing updated or checked.' % path)
if current == 'error':
raise BadReadme('measures_update: the measures readme.txt file at %s could not be read as expected, an update can not proceed unless force is True' % path)
# don't overwrite something that looks like valid measures data unless forced to do so
if current == 'unknown':
print_log_messages('measures_update: the measures data at %s is not maintained by casaconfig and so it can not be updated unless force is True' % path, logger)
return
checkVersion = version
if checkVersion is None:
# get the current most recent version
try:
checkVersion = measures_available()[-1]
except RemoteError as exc:
# no network, no point in continuing, just reraise
raise exc
except:
# unsure what happened, leave it at none, which will trigger an update attempt, which might work
pass
# don't re-download the same data
if (checkVersion is not None) and (checkVersion == current):
if verbose > 0:
print_log_messages('measures_update: requested version already installed in %s' % path, logger, verbose=verbose)
# update the age of the readme to now
readme_path = os.path.join(path,'geodetic/readme.txt')
# readme_path should already exist if it's here
os.utime(readme_path)
return
# don't do anything unless the Observatories table is already installed as expected
obsTabPath = os.path.join(path,'geodetic/Observatories')
if not os.path.isdir(obsTabPath):
msgs = []
msgs.append("Error: the Observatories table was not found as expected in %s" % path)
msgs.append("Either install casarundata first or set use_astron_obs_table and force to be True when using measures_update.")
msgs.append("Note that the Observatories table provided in the Astron measures tarfile is not the same as that maintained by CASA")
print_log_messages(msgs, logger, True)
return
# path must be writable with execute bit set
if (not os.access(path, os.W_OK | os.X_OK)) :
raise NotWritable('measures_update: No permission to write to path, cannot update : %s' % path)
# an update needs to happen
# lock the measures_update.lock file
lock_fd = None
clean_lock = True # set to false if the contents are actively being update and the lock file should not be cleaned one exception
try:
print_log_messages('measures_update ... acquiring the lock ... ', logger)
# the BadLock exception that may happen here is caught below
lock_fd = get_data_lock(path, 'measures_update')
do_update = force
if not do_update:
# recheck the readme file, another update may have already happened before the lock was obtained
current = None
ageRecent = False
readmeInfo = get_data_info(path, logger, type='measures')
if readmeInfo is not None:
current = readmeInfo['version']
if readmeInfo['age'] is not None:
ageRecent = readmeInfo['age'] < 1.0
if (version is not None) and (version == current):
# no update will be done, version is as requested - always verbose here because the lock is in use
print_log_messages('The requested measures version is already installed in %s, using version %s' % (path, current), logger)
elif (version is None) and ageRecent:
# no update will be done, it's already been checked or updated recently - always verbose here because the lock is in use
print_log_messages('The latest measures version was checked recently in %s, using version %s' % (path, current), logger)
else:
# final check for problems before updating
if not force and readmeInfo is not None and (version=='invalid' or version=='unknown'):
# at this point, this indicates something is unexpectedly wrong, do not continue
# this exception is caught below
# do not clean up the lock file
clean_lock = False
raise BadReadme('measures_update: something unexpected has changed in the path location, can not continue')
else:
# an update is needed
do_update = True
if do_update:
if force:
print_log_messages('A measures update has been requested by the force argument', logger)
print_log_messages(' ... finding available measures at www.astron.nl ...', logger)
files = measures_available()
# target filename to download
# for the non-force unspecified version case this can only get here if the age is > 1 day so there should be a newer version
# but that isn't checked - this could install a version that's already installed
target = files[-1] if version is None else version
if target not in files:
print_log_messages("measures_update can't find specified version %s" % target, logger, True)
else:
# there are files to extract
print_log_messages(' ... downloading %s from ASTRON server to %s ...' % (target, path), logger)
astronURL = 'https://www.astron.nl/iers'
context = ssl.create_default_context(cafile=certifi.where())
# just in case there's a redirect at astron the way there is for the go.nrao.edu site and casarundata
measuresURLroot = urllib.request.urlopen(astronURL, context=context).url
measuresURL = os.path.join(measuresURLroot, target)
# it's at this point that this code starts modifying what's there so the lock file should
# not be removed on failure after this although it may leave that temp tar file around, but that's OK
clean_lock = False
# remove any existing measures readme.txt now in case something goes wrong during extraction
readme_path = os.path.join(path,'geodetic/readme.txt')
if os.path.exists(readme_path):
os.remove(readme_path)
# custom filter that incorporates data_filter to watch for dangerous members of the tar file and
# add filtering to remove the Observatories table (unless use_astron_obs_table is True) and
# the *.old tables that may be in the geodetic tree
def custom_filter(member, extractionPath):
# member is a TarInfo instance and extractionPath is the destination path
# use the 'data_filter' first to deal with dangerous members
member = tarfile.data_filter(member, extractionPath)
# always exclude *.old names in geodetic
if (member is not None) and (re.search('geodetic',member.name) and re.search('.old',member.name)):
member = None
# the use_astron_obs_table argumen only has weight if force is True
if (not (force and use_astron_obs_table)) and (member is not None) and (re.search('Observatories',member.name)):
member = None
return member
with urllib.request.urlopen(measuresURL, context=context, timeout=400) as tstream, tarfile.open(fileobj=tstream, mode='r|*') as tar :
# use the 'data' filter if available, revert to previous 'fully_trusted' behavior of not available
tar.extraction_filter = custom_filter
tar.extractall(path=path)
tar.close()
# create a new readme.txt file
with open(readme_path,'w') as fid:
fid.write("# measures data populated by casaconfig\nversion : %s\ndate : %s" % (target, datetime.today().strftime('%Y-%m-%d')))
clean_lock = True
print_log_messages(' ... measures data updated at %s' % path, logger)
# closing out the do_update
# closing out the try block
except BadLock as exc:
# the path is known to exist so this means that the lock file was not empty and it's not locked
msgs = [str(exc)]
msgs.append('The lock file at %s is not empty.' % path)
msgs.append('A previous attempt to update path may have failed or exited prematurely.')
msgs.append('Remove the lock file and set force to True with the desired version (default to most recent).')
msgs.append('It may be best to completely repopulate path using pull_data and measures_update.')
print_log_messages(msgs, logger, True)
# reraise this
raise
except BadReadme as exc:
# something is wrong in the readme after an update was triggered, this shouldn't happen, print more context and reraise this
msgs = [str(exc)]
msgs.append('This should not happen unless multiple sessions are trying to update data at the same time and one experienced problems or was done out of sequence')
msgs.append('Check for other updates in progress or choose a different path or clear out this path and reinstall the casarundata as well as the measures data')
print_log_messages(msgs, logger, True)
raise
except Exception as exc:
msgs = []
msgs.append("ERROR! : Unexpected exception while updating measures at %s" % path)
msgs.append("ERROR! : %s" % exc)
print_log_messages(msgs, logger, True)
raise
finally:
# make sure the lock file is closed and also clean the lock file if safe to do so, this is always executed
if lock_fd is not None and not lock_fd.closed:
if clean_lock:
lock_fd.truncate(0)
lock_fd.close()
return