Loki stores your logs and only indexes labels for each log stream. Using Loki with Grafana Alerting is a powerful way to keep track of what’s happening in your environment. You can create metric alert rules based on content in your log lines to notify your team. What’s even better is that you can add label data from the log message directly into your alert notification.
Check out our [advanced alerting tutorial](https://grafana.com/tutorials/alerting-get-started-pt2/) to explore advanced topics such as alert instances and notification routing.
> Check out our [advanced alerting tutorial](https://grafana.com/tutorials/alerting-get-started-pt2/) to explore advanced topics such as alert instances and notification routing.
The first time you run `docker compose up -d`, Docker downloads all the necessary resources for the tutorial. This might take a few minutes, depending on your internet connection.
If you already have Grafana, Loki, or Prometheus running on your system, you might see errors, because the Docker image is trying to use ports that your local installations are already using. If this is the case, stop the services, then run the command again.
> If you already have Grafana, Loki, or Prometheus running on your system, you might see errors, because the Docker image is trying to use ports that your local installations are already using. If this is the case, stop the services, then run the command again.
Alternatively, you can try out this example in our interactive learning environment: [Get started with Grafana Alerting](https://killercoda.com/grafana-labs/course/grafana/alerting-get-started/).
Besides being an open-source observability tool, Grafana has its own built-in alerting service. This means that you can receive notifications whenever there is an event of interest in your data, and even see these events graphed in your visualizations.
In this step, we'll set up a new [contact point](https://grafana.com/docs/grafana/latest/alerting/configure-notifications/manage-contact-points/integrations/webhook-notifier/). This contact point will use the _webhooks_ integration. In order to make this work, we also need an endpoint for our webhook integration to receive the alert. We will use [Webhook.site](https://webhook.site/) to quickly set up that test endpoint. This way we can make sure that our alert is actually sending a notification somewhere.
1. Return to Grafana. In Grafana's sidebar, hover over the **Alerting** (bell) icon and then click **Contact points**.
1. Click **+ Add contact point**.
1. In **Name**, write **Webhook**.
1. In **Integration**, choose **Webhook**.
1. In **URL**, paste the endpoint to your webhook endpoint.
1. Click **Test**, and then click **Send test notification** to send a test alert to your webhook endpoint.
1. Navigate back to [Webhook.site](https://webhook.site/). On the left side, there's now a `POST /` entry. Click it to see what information Grafana sent.
We have created a dummy Webhook endpoint and created a new Alerting contact point in Grafana. Now, we can create an alert rule and link it to this new integration.
Next, we'll establish an [alert rule](http://grafana.com/docs/grafana/next/alerting/fundamentals/alert-rule-evaluation/) within Grafana Alerting to notify us whenever alert rules are triggered and resolved.
1. In Grafana, **navigate to Alerting** > **Alert rules**.
1. Click on **New alert rule**.
1. Enter alert rule name for your alert rule. Make it short and descriptive as this will appear in your alert notification. For instance, **web-requests-logs**
This query will count the number of log lines with a status code that is not 200 (OK), then sum the result set by message type using an **instant query** and the time interval indicated in brackets. It uses the LogQL pattern parser to add a new label called `message` that contains the level, method, url, and status from the log line.
You can use the **explain query** toggle button for a full explanation of the query syntax. The optional log-generating script creates a sample log line similar to the one below:
If you're using your own logs, modify the LogQL query to match your own log message. Refer to the Loki docs to understand the [pattern parser](https://grafana.com/docs/loki/latest/logql/log_queries/#pattern).
If you're using your own logs, modify the LogQL query to match your own log message. Refer to the Loki docs to understand the [pattern parser](https://grafana.com/docs/loki/latest/logql/log_queries/#pattern).
4. Remove the ‘B’**Reduce expression** (click the bin icon). The Reduce expression comes by default, and in this case, it is not needed since the queried data is already reduced. Note that the Threshold expression is now your **Alert condition**.
It should return alert instances from log lines with a status code that is not 200 (OK), and that has met the alert condition. The condition for the alert rule to fire is any occurrence that goes over the threshold of `0`. Since the Loki query has returned more than zero alert instances, the alert rule is `Firing`.
An [evaluation group](https://grafana.com/docs/grafana/latest/alerting/fundamentals/alert-rules/rule-evaluation/) defines when an alert rule fires, and it’s based on two settings:
- **Evaluation group**: how frequently the alert rule is evaluated.
- **Evaluation interval**: how long the condition must be met to start firing. This allows your data time to stabilize before triggering an alert, helping to reduce the frequency of unnecessary notifications.
Since the Python script will continue to generate log data that matches the alert rule condition, once the evaluation interval has concluded, you should receive an alert notification in the Webhook endpoint.
Advance your skills by exploring [alert instances and notification routing](http://grafana.com/tutorials/alerting-get-started-pt2/) in Part 2 of your learning journey.
> Advance your skills by exploring [alert instances and notification routing](http://grafana.com/tutorials/alerting-get-started-pt2/) in Part 2 of your learning journey.
