loki.source.api.md

---

title: loki.source.api

---

loki.source.api

loki.source.api receives log entries over HTTP and forwards them to other loki.* components.

The HTTP API exposed is compatible with [Loki push API][loki-push-api] and the logproto format. This means that other [loki.write][loki.write] components can be used as a client and send requests to loki.source.api which enables using the Agent as a proxy for logs.

[loki.write]: {{< relref "./loki.write.md" >}} [loki-push-api]: https://grafana.com/docs/loki/latest/api/#push-log-entries-to-loki

Usage

loki.source.api "LABEL" {
    http {
        listen_address = "LISTEN_ADDRESS"
        listen_port = PORT 
    }
    forward_to = RECEIVER_LIST
}

The component will start HTTP server on the configured port and address with the following endpoints:

• /api/v1/push - accepting POST requests compatible with [Loki push API][loki-push-api], for example, from another Grafana Agent's [loki.write][loki.write] component.

• /api/v1/raw - accepting POST requests with newline-delimited log lines in body. This can be used to send NDJSON or plaintext logs. This is compatible with promtail's push API endpoint - see promtail's documentation for more information. NOTE: when this endpoint is used, the incoming timestamps cannot be used and the use_incoming_timestamp = true setting will be ignored.

• /ready - accepting GET requests - can be used to confirm the server is reachable and healthy.

Arguments

loki.source.api supports the following arguments:

Name	Type	Description	Default	Required
forward_to	list(LogsReceiver)	List of receivers to send log entries to.		yes
use_incoming_timestamp	bool	Whether or not to use the timestamp received from request.	false	no
labels	map(string)	The labels to associate with each received logs record.	{}	no
relabel_rules	RelabelRules	Relabeling rules to apply on log entries.	{}	no

The relabel_rules field can make use of the rules export value from a [loki.relabel][loki.relabel] component to apply one or more relabeling rules to log entries before they're forwarded to the list of receivers in forward_to.

[loki.relabel]: {{< relref "./loki.relabel.md" >}}

Blocks

The following blocks are supported inside the definition of loki.source.heroku:

Hierarchy	Name	Description	Required
http	http	Configures the HTTP server that receives requests.	no

http

{{< docs/shared lookup="flow/reference/components/loki-server-http.md" source="agent" >}}

Exported fields

loki.source.api does not export any fields.

Component health

loki.source.api is only reported as unhealthy if given an invalid configuration.

Debug metrics

The following are some of the metrics that are exposed when this component is used. Note that the metrics include labels such as status_code where relevant, which can be used to measure request success rates.

• loki_source_api_request_duration_seconds (histogram): Time (in seconds) spent serving HTTP requests.

• loki_source_api_request_message_bytes (histogram): Size (in bytes) of messages received in the request.

• loki_source_api_response_message_bytes (histogram): Size (in bytes) of messages sent in response.

• loki_source_api_tcp_connections (gauge): Current number of accepted TCP connections.

Example

This example starts an HTTP server on 0.0.0.0 address and port 9999. The server receives log entries and forwards them to a loki.write component while adding a forwarded="true" label. The loki.write component will send the logs to the specified loki instance using basic auth credentials provided.

loki.write "local" {
    endpoint {
        url = "http://loki:3100/api/v1/push"
        basic_auth {
            username = "<your username>"
            password_file = "<your password file>"
        }
    }
}

loki.source.api "loki_push_api" {
    http {
        listen_address = "0.0.0.0"
        listen_port = 9999
    }
    forward_to = [
        loki.write.local.receiver,
    ]
    labels = {
        forwarded = "true",
    }
}