Prometheus exporter for barman

barman_exporter.conf

# vim: set ft=dosini:
# Supervisord config for the barman exporter

[program:barman_exporter]
environment=PATH=/usr/local/bin:%(ENV_PATH)s
command=/usr/local/bin/env python3 /var/barman/barman_exporter.py
user=barman
autostart=true
stopasgroup=true
killasgroup=true
autorestart=true
startretries=10000
stderr_logfile=/var/log/%(program_name)s.err.log
stdout_logfile=/var/log/%(program_name)s.out.log
stdout_logfile_maxbytes=200MB
stdout_logfile_backups=1
stderr_logfile_maxbytes=200MB
stderr_logfile_backups=1

barman_prometheus_exporter.py

#!/usr/bin/env python3.6

import sys
import time
import contextlib
import collections
from datetime import datetime

import prometheus_client
from prometheus_client import core
from barman import cli
from barman import output
from barman import backup
from barman.server import CheckOutputStrategy


class Output(output.ConsoleOutputWriter):
    results = collections.defaultdict(dict)

    def result_check(self, server_name, check, status, hint=None):
        self.results[check] = dict(status=status, hint=hint)


class BarmanCollector:

    def __init__(self, args):
        self.args = args
        self.results = output._writer.results

    def collect(self):
        cli.global_config(self.args)
        servers = cli.get_server_list(self.args)

        collectors = dict(
            barman_backups=core.GaugeMetricFamily(
                'barman_backups', 'total backups available',
                labels=['server']),
            barman_last_backup=core.GaugeMetricFamily(
                'barman_last_backup', 'last backup timestamp',
                labels=['server']),
            barman_last_backup_age=core.GaugeMetricFamily(
                'barman_last_backup_age', 'seconds since last backup',
                labels=['server']),
            barman_status=core.GaugeMetricFamily(
                'barman_status', 'Several barman status checks',
                labels=['server', 'check'])
        )

        for server_name, server in servers.items():
            backups = len(server.backup_manager.get_available_backups(
                status_filter=(backup.BackupInfo.DONE,)))
            collectors['barman_backups'].add_metric([server_name], backups)

            last_backup = server.backup_manager.get_last_backup_id()
            if last_backup:
                now = datetime.now()
                last_backup = datetime.strptime(last_backup, '%Y%m%dT%H%M%S')
                collectors['barman_last_backup'].add_metric(
                    [server_name], time.mktime(last_backup.timetuple()))
                collectors['barman_last_backup_age'].add_metric(
                    [server_name], (now - last_backup).total_seconds())

            with contextlib.closing(server):
                check_strategy = CheckOutputStrategy()
                # Check WAL archive
                server.check_archive(check_strategy)
                # Postgres configuration is not available on passive nodes
                if not server.passive_node:
                    server.check_postgres(check_strategy)
                # Check barman directories from barman configuration
                server.check_directories(check_strategy)
                # Check retention policies
                server.check_retention_policy_settings(check_strategy)
                # Check for backup validity
                server.check_backup_validity(check_strategy)
                # Executes the backup manager set of checks
                server.backup_manager.check(check_strategy)
                # Check if the msg_list of the server
                # contains messages and output eventual failures
                server.check_configuration(check_strategy)

                # Executes check() for every archiver, passing
                # remote status information for efficiency
                for archiver in server.archivers:
                    archiver.check(check_strategy)

                # Check archiver errors
                server.check_archiver_errors(check_strategy)

            collector = collectors['barman_status']
            for name, value in self.results.items():
                key = name.replace(' ', '_').replace('-', '_').lower()
                if value['hint']:
                    continue

                collector.add_metric([server_name, key], int(value['status']))

        for collector in collectors.values():
            yield collector


if __name__ == '__main__':
    output.set_output_writer(Output())

    class Args:
        server_name = ['all']
        quiet = output._writer
        debug = output._writer
        color = 'auto'
        format = debug

    args = Args()
    core.REGISTRY.register(BarmanCollector(args))

    # Start up the server to expose the metrics.
    prometheus_client.start_http_server(8000)
    # Generate some requests.
    while True:
        time.sleep(1)

My pull request with JSON output formatter has been added to Barman 2.9+ and now we can use it. I store the metrics as textfile which is digested by node-exporter. It works better that way because executing barman commands can take a while (even minutes).

Barman exporter here: https://github.com/ahes/prometheus-barman-exporter
You can also install barman-exporter with pip:

pip3 install barman-exporter

Excellent work, that looks great already.

Adding server.backup_manager._backup_cache = None before you use the backup_manager makes sure that backup_manager obtains any new backups, fixing the exporter not updating after a new backup.