Best way to scrape metric from a custom service

dilawar · August 16, 2021, 5:28am

I have grafana-agent on a Linux node and I am getting the metric into the dashboard. So far, so good.

I have a custom script (say foo.py) that computes some matrices. Currently, I am writing these metrics onto console. I am thinking of appending these metrics to a file let the node_exporter's textfile collector collects the metric. Is this a decent approach?

If I take this route, I have a question:

Can foo.py appending metrics to a prom file and file textfile will keep track of what is new in the metrics file? Or should I delete the old file and create a new one every time there is a new metric?

Is there any other solution to this problem?

mattabrams · October 5, 2021, 4:04am

I really like using the textfile collector. But, I’ve also used the python prometheus client to record the output from a periodic script, and it works even better.

This is mostly boilerplate code and maybe a useful place to start re the exporter:

github.com

zuchka/grafana-docs-exporter/blob/main/exporter.py

import time, re
from prometheus_client.core import GaugeMetricFamily, REGISTRY
from prometheus_client import start_http_server
from script import script

results = script()

# iterate over results and add metrics for each url in grafana docs
class CustomCollector(object):
    def __init__(self):
        pass

    def collect(self):
        for result in results:
            for item in result:
                if re.match(r'^https', item):
                    g = GaugeMetricFamily("flesch_score", 'flesch reading ease score per URL', labels=["url"])
                    g.add_metric([item], result[item])
                    yield g
                elif re.match(r'^flesch_average', item):

This file has been truncated. show original

Otherwise I often refer to this article for more details on using the textfile collector:
https://www.robustperception.io/tag/textfile-collector

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Best way to scrape metric from a custom service

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