The Ops Community ⚙️

Alex
Alex

Posted on

loki && curl && logcli

#devops #loki #logs #sre

With https://community.ops.io/la3mmchen/grafana-loki-28b9 I've shared some words on Loki as an introduction.

Lets follow up with some practical stuff: How can we run Loki an our local notebook with docker-compose?

Loki

As Grafana provides a good enough container images we just use the one from docker hub to get a local instance running.

---
version: "3.9"

services:
  loki:
    image: "grafana/loki:2.5.0"
    ports:
      - "3100:3100"
Enter fullscreen mode Exit fullscreen mode

As Loki follows the unix philosophy "Do One Thing and Do It Well" it's just a backend to send logs to and to query logs from.
Plain speaking: there is no graphical user interface in the Loki server.

We interact with the Loki instance with curl using the http api:

$  curl http://localhost:3100/ready  
ready
$ curl http://localhost:3100/loki/api/v1/labels
{"status":"success","data":["__name__"]}
Enter fullscreen mode Exit fullscreen mode

As the second request shows there are not many labels in the system yet.

Lets change this.

interact with curl

Loki offers a http api to send metrics. The data format is described at http push api, we use the following curl to create a new event stream:

$ curl -S -H "Content-Type: application/json" -XPOST -s http://localhost:3100/loki/api/v1/push --data-raw '{"streams": [{ "stream": { "app": "app1" }, "values": [ [ "1653855518000000000", "random log line" ] ] }]}'
$ curl http://localhost:3100/loki/api/v1/labels
{"status":"success","data":["__name__","app"]}
Enter fullscreen mode Exit fullscreen mode

As you can see in the second curl there is now a new label named "app". We can explore possible values for this label with the following curl.

$ curl http://localhost:3100/loki/api/v1/label/app/values
{"status":"success","data":["app1"]}
Enter fullscreen mode Exit fullscreen mode

And finaly see the stream with this label:

$ curl -G -Ss  http://localhost:3100/loki/api/v1/query_range --data-urlencode 'query={app="app1"}' | jq .
{
  "status": "success",
(...)
        "values": [
          [
            "1653855518000000000",
            "random log line"
          ]
        ]
      }
(...)
Enter fullscreen mode Exit fullscreen mode

(output shorted)

logcli

A more covenient way to interact with Loki from the command line is using logcli

$ LOKI_ADDR=http://localhost:3100 logcli labels
http://localhost:3100/loki/api/v1/labels?end=1653856566774536000&start=1653852966774536000
__name__
app
$ LOKI_ADDR=http://localhost:3100 logcli query '{app=~".+"}'
http://localhost:3100/loki/api/v1/query_range?direction=BACKWARD&end=1653856568404563000&limit=30&query=%7Bapp%3D~%22.%2B%22%7D&start=1653852968404563000
Common labels: {app="app1"}
2022-05-29T22:18:38+02:00 {} random log line
http://localhost:3100/loki/api/v1/query_range?direction=BACKWARD&end=1653855518000000001&limit=30&query=%7Bapp%3D~%22.%2B%22%7D&start=1653852968404563000
Common labels: {app="app1"}
Enter fullscreen mode Exit fullscreen mode

in case you do not want to install logcli locally just add another container to our docker-compose setup from the beginning of this article:

(..)
  logcli:
    image: "grafana/logcli:2.5.0-amd64"
    environment:
      - "LOKI_ADDR=http://loki:3100"
Enter fullscreen mode Exit fullscreen mode

with this container you can just do:

$ docker-compose run logcli labels
Creating loki_logcli_run ... done
(..)
__name__
app
Enter fullscreen mode Exit fullscreen mode

following up

in the next post we will add a grafana instance to our docker-compose that will enable us to click something ;-)

references

links

code reference 

---
version: "3.9"

services:
  loki:
    image: "grafana/loki:2.5.0"
    ports:
      - "3100:3100"
  logcli:
    image: "grafana/logcli:2.5.0-amd64"
    environment:
      - "LOKI_ADDR=http://loki:3100"
Enter fullscreen mode Exit fullscreen mode

Top comments (9)

Collapse
 
burger_kingmenu_d4ae2673 profile image
Burger King Menu •

Thanks for sharing! I found this really helpful. By the way, if anyone’s looking for an updated list, check out the full Burger King Menue with prices—it’s super easy to navigate and really detailed!

Collapse
 
panada_expressmenu_3450d profile image
Panada Express Menu •

Great tips here! Also, for anyone looking for the latest Panda Express offerings, check out the full Panda Menu—it’s super easy to browse and see all the options available!

Collapse
 
wendys_menu_9d16407a981c profile image
Wendy's Menu •

Nice write-up! If you're looking for a quick, delicious option while working, check out our Wendys Menu—complete, easy to browse, and perfect when you need something tasty on the go!

Collapse
 
jack_intheboxmenu_9ed5 profile image
Jack in the box menu •

Nice write-up! By the way, if you're craving a quick, tasty bite while tinkering with this setup, take a peek at our Jack in the Box Tacos Menu—easy to browse and perfect fuel for your dev workflow!

Collapse
 
jackbox profile image
Jack in the Box Menu •

Great guide on getting Loki up and running locally with Docker! For anyone diving into monitoring and logs, setting this up is a great first step. If you're looking for a quick bite while working through this setup, why not check out Jack in the Box? Their menu has a wide variety of options that can keep you fueled. You can easily find a Jack in the Box menu near me for some delicious burgers, tacos, or breakfast items. Perfect for a snack between tasks!

Collapse
 
aiman_fareed_af7c8b6dcb72 profile image
Aiman fareed •

Enjoy Whataburger’s cozy Cinnamon Roll, crispy Hot Apple Pie, and tasty Chocolate Chunk Cookie for a perfect sweet treat anytime. These desserts deliver comforting flavors that satisfy cravings on the go. Explore all available options and prices at the Whataburger irresistible dessert menu today!

Collapse
 
nntech_ce34765219fe9625b6 profile image
nntech •

Kick off your morning with the 2025 breakfast menu’s savory tacos, warm kolaches, and fresh pastries. Perfect for a quick and delicious start. Explore the full menu and prices at the breakfast essentials spot today.

Collapse
 
aiman_fareed_af7c8b6dcb72 profile image
Aiman fareed • • Edited

Loved reading this! For anyone curious about beverages, this Complete drink menuis a quick reference to what’s available.

Collapse
 
aiman_fareed_af7c8b6dcb72 profile image
Aiman fareed •

Nice write-up! When you’re done troubleshooting, this Menu guide for Troy
helps you plan a quick dinner with friends.