Multiprocessing: missing counter and summary

I am experimenting with client_python and I am trying to set metrics on multiprocessing application. Imitating the README and tests (test_multiprocess) I ended with this code which doesn’t work:

from prometheus_client import multiprocess
from prometheus_client import generate_latest, Gauge, Counter, Summary, REGISTRY
import os
import time
import tempfile
import shutil

class Metrics(object):
    def __init__(self, idx):
        # make temp dir
        self._tempdir = tempfile.mkdtemp()
        # set os environment variable
        os.environ['prometheus_multiproc_dir'] = self._tempdir

        self._registry = REGISTRY
        self._multiprocess_registry = multiprocess.MultiProcessCollector(self._registry, self._tempdir)

        idx = str(idx)
        self.GAUGE_THREAD_POOL = Gauge('context_thread_pool_' + idx, 'Number of threads used', multiprocess_mode='all')
        self.COUNTER_APP_CALLS = Counter('context_app_calls_' + idx, 'Number of calls', registry=None, namespace='app_')
        self.COUNTER_APP_SUCCESS = Counter('context_app_success_' + idx, 'Number of successful calls', registry=None, namespace='app_')
        self.COUNTER_APP_FAILURE = Counter('context_app_failure_' + idx, 'Number of failed calls', registry=None, namespace='app_')
        self.SUMMARY_APP = Summary('context_app_' + idx, 'Time spent on app', registry=None, namespace='app_')

    def shutdown(self):
        # remove the temporary directory
        shutil.rmtree(self._tempdir)

    def collect(self):
        return generate_latest(self._registry).decode()


m = Metrics(idx=1)
m.GAUGE_THREAD_POOL.inc(3)
m.COUNTER_APP_CALLS.inc(1)
m.SUMMARY_APP.observe(3.14)

print(m.collect())

The last print misses counter and summary:

# HELP context_thread_pool_1 Number of threads used
# TYPE context_thread_pool_1 gauge
context_thread_pool_1 3.0

Version:

> pip3 show prometheus_client
Name: prometheus-client
Version: 0.0.19

> python3 --version
Python 3.5.3

Can you please suggest any change that will make the above code produce the correct summary of the registry?

[brian-brazil]

There isn’t currently. The right number coming out is the important thing.

[csmarchbanks]

Are you using multiprocess mode as described in the README?

Also, please open a new Github discussion or ask on the prometheus-users mailing-list rather than asking on a closed issue.