def setup_prometheus_multiproc(async_mode):
"""Setup prometheus_client multiprocess support.
This involves setting up locking and a temporary directory if needed.
Note: if we can't create the lock (e.g. inside a strictly confined snap
package) then multiprocess cleanup is *not* enabled.
"""
global _lock, registry, try_prometheus_lock
if not prometheus_installed:
return
if 'prometheus_multiproc_dir' not in os.environ:
prefix = 'prometheus_multiproc_{}_'.format(os.getpid())
tmp = tempfile.mkdtemp(prefix=prefix)
os.environ['prometheus_multiproc_dir'] = tmp
# try enable multiprocess cleanup
try:
_lock = Lock()
except OSError as exc:
if exc.errno != errno.EACCES:
raise
early_log(
__name__,
'warning',
'Unable to create lock for prometheus, cleanup disabled',
)
else:
if async_mode:
try_prometheus_lock = try_prometheus_lock_patched_async
else:
try_prometheus_lock = try_prometheus_lock_normal
# signal to others that clean up is enabled
talisker.prometheus_multiproc_cleanup = True
early_log(__name__,
'info',
'prometheus_client is in multiprocess mode',
extra={
'multiproc_dir': os.environ['prometheus_multiproc_dir'],
'cleanup_enabled': talisker.prometheus_multiproc_cleanup,
})
if future.utils.PY3:
import contextvars
# enable asyncio aware contextvars in 3.5.3+/3.6
if pkg_is_installed('aiocontextvars'):
import asyncio
# aiocontextvars only supports python 3.5.3+
if hasattr(asyncio, '_get_running_loop'):
import aiocontextvars # NOQA
else:
early_log(
__name__,
'warning',
'aiocontextvars is installed, but it does not function with '
'python {}. Please use python >= 3.5.3 if you wish to use '
'talisker with asyncio.'.format(
'.'.join(str(v) for v in sys.version_info[:3])
)
)
ContextId = contextvars.ContextVar('talisker')
CONTEXT_OBJ = contextvars
CONTEXT_ATTR = '_state'
else:
_NONE = object()
class Python2ContextVar():
"""Tiny python2 implementation of ContextVar, enough for our purposes.
It is not immutable, and it does not support the reset(token) API. But