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discovery.http

Open source

discovery.http

discovery.http provides a flexible way to define targets by querying an external http endpoint.

It fetches targets from an HTTP endpoint containing a list of zero or more target definitions. The target must reply with an HTTP 200 response. The HTTP header Content-Type must be application/json, and the body must be valid JSON.

Example response body:

[
  {
    "targets": [ "<host>", ... ],
    "labels": {
      "<labelname>": "<labelvalue>", ...
    }
  },
  ...
]

It is possible to use additional fields in the JSON to pass parameters to prometheus.scrape such as the metricsPath and scrape_interval.

As an example, the following will provide a target with a custom metricsPath, scrape interval, and timeout value:

[
   {
      "labels" : {
         "__metrics_path__" : "/api/prometheus",
         "__scheme__" : "https",
         "__scrape_interval__" : "60s",
         "__scrape_timeout__" : "10s",
         "service" : "custom-api-service"
      },
      "targets" : [
         "custom-api:443"
      ]
   },
]

It is also possible to append query parameters to the metrics path with the __param_<name> syntax.

For example, the following will call a metrics path of /health?target_data=prometheus:

[
   {
      "labels" : {
         "__metrics_path__" : "/health",
         "__scheme__" : "https",
         "__scrape_interval__" : "60s",
         "__scrape_timeout__" : "10s",
         "__param_target_data": "prometheus",
         "service" : "custom-api-service"
      },
      "targets" : [
         "custom-api:443"
      ]
   },
]

For more information on the potential labels you can use, see the prometheus.scrape technical details section, or the Prometheus Configuration documentation.

Usage

discovery.http "LABEL" {
  url = URL
}

Arguments

The following arguments are supported:

Name	Type	Description	Default	Required
`url`	`string`	URL to scrape.		yes
`refresh_interval`	`duration`	How often to refresh targets.	`"60s"`	no
`bearer_token_file`	`string`	File containing a bearer token to authenticate with.		no
`bearer_token`	`secret`	Bearer token to authenticate with.		no
`enable_http2`	`bool`	Whether HTTP2 is supported for requests.	`true`	no
`follow_redirects`	`bool`	Whether redirects returned by the server should be followed.	`true`	no
`proxy_url`	`string`	HTTP proxy to send requests through.		no
`no_proxy`	`string`	Comma-separated list of IP addresses, CIDR notations, and domain names to exclude from proxying.		no
`proxy_from_environment`	`bool`	Use the proxy URL indicated by environment variables.	`false`	no
`proxy_connect_header`	`map(list(secret))`	Specifies headers to send to proxies during CONNECT requests.		no

At most, one of the following can be provided:

bearer_token argument.
bearer_token_file argument.
basic_auth block.
authorization block.
oauth2 block.

no_proxy can contain IPs, CIDR notations, and domain names. IP and domain names can contain port numbers. proxy_url must be configured if no_proxy is configured.

proxy_from_environment uses the environment variables HTTP_PROXY, HTTPS_PROXY and NO_PROXY (or the lowercase versions thereof). Requests use the proxy from the environment variable matching their scheme, unless excluded by NO_PROXY. proxy_url and no_proxy must not be configured if proxy_from_environment is configured.

proxy_connect_header should only be configured if proxy_url or proxy_from_environment are configured.

Blocks

The following blocks are supported inside the definition of discovery.http:

Hierarchy	Block	Description	Required
basic_auth	basic_auth	Configure basic_auth for authenticating to the endpoint.	no
authorization	authorization	Configure generic authorization to the endpoint.	no
oauth2	oauth2	Configure OAuth2 for authenticating to the endpoint.	no
oauth2 > tls_config	tls_config	Configure TLS settings for connecting to the endpoint.	no
tls_config	tls_config	Configure TLS settings for connecting to the endpoint.	no

The > symbol indicates deeper levels of nesting. For example, oauth2 > tls_config refers to a tls_config block defined inside an oauth2 block.

basic_auth block

Name	Type	Description	Required
`password_file`	`string`	File containing the basic auth password.	no
`password`	`secret`	Basic auth password.	no
`username`	`string`	Basic auth username.	no

password and password_file are mutually exclusive, and only one can be provided inside a basic_auth block.

authorization block

Name	Type	Description	Required
`credentials_file`	`string`	File containing the secret value.	no
`credentials`	`secret`	Secret value.	no
`type`	`string`	Authorization type, for example, “Bearer”.	no

credential and credentials_file are mutually exclusive, and only one can be provided inside an authorization block.

oauth2 block

Name	Type	Description	Default	Required
`client_id`	`string`	OAuth2 client ID.		no
`client_secret_file`	`string`	File containing the OAuth2 client secret.		no
`client_secret`	`secret`	OAuth2 client secret.		no
`endpoint_params`	`map(string)`	Optional parameters to append to the token URL.		no
`proxy_url`	`string`	HTTP proxy to send requests through.		no
`no_proxy`	`string`	Comma-separated list of IP addresses, CIDR notations, and domain names to exclude from proxying.		no
`proxy_from_environment`	`bool`	Use the proxy URL indicated by environment variables.	`false`	no
`proxy_connect_header`	`map(list(secret))`	Specifies headers to send to proxies during CONNECT requests.		no
`scopes`	`list(string)`	List of scopes to authenticate with.		no
`token_url`	`string`	URL to fetch the token from.		no

client_secret and client_secret_file are mutually exclusive, and only one can be provided inside an oauth2 block.

The oauth2 block may also contain a separate tls_config sub-block.

no_proxy can contain IPs, CIDR notations, and domain names. IP and domain names can contain port numbers. proxy_url must be configured if no_proxy is configured.

proxy_connect_header should only be configured if proxy_url or proxy_from_environment are configured.

tls_config block

Name	Type	Description	Required
`ca_pem`	`string`	CA PEM-encoded text to validate the server with.	no
`ca_file`	`string`	CA certificate to validate the server with.	no
`cert_pem`	`string`	Certificate PEM-encoded text for client authentication.	no
`cert_file`	`string`	Certificate file for client authentication.	no
`insecure_skip_verify`	`bool`	Disables validation of the server certificate.	no
`key_file`	`string`	Key file for client authentication.	no
`key_pem`	`secret`	Key PEM-encoded text for client authentication.	no
`min_version`	`string`	Minimum acceptable TLS version.	no
`server_name`	`string`	ServerName extension to indicate the name of the server.	no

The following pairs of arguments are mutually exclusive and can’t both be set simultaneously:

ca_pem and ca_file
cert_pem and cert_file
key_pem and key_file

When configuring client authentication, both the client certificate (using cert_pem or cert_file) and the client key (using key_pem or key_file) must be provided.

When min_version is not provided, the minimum acceptable TLS version is inherited from Go’s default minimum version, TLS 1.2. If min_version is provided, it must be set to one of the following strings:

"TLS10" (TLS 1.0)
"TLS11" (TLS 1.1)
"TLS12" (TLS 1.2)
"TLS13" (TLS 1.3)

Exported fields

The following fields are exported and can be referenced by other components:

Name	Type	Description
`targets`	`list(map(string))`	The set of targets discovered from the filesystem.

Each target includes the following labels:

__meta_url: URL the target was obtained from.

Component health

discovery.http is only reported as unhealthy when given an invalid configuration. In those cases, exported fields retain their last healthy values.

Debug information

discovery.http does not expose any component-specific debug information.

Debug metrics

prometheus_sd_http_failures_total (counter): Total number of refresh failures.

Examples

This example will query a url every 15 seconds and expose targets that it finds:

discovery.http "dynamic_targets" {
  url = "https://example.com/scrape_targets"
  refresh_interval = "15s"
}

Compatible components

discovery.http has exports that can be consumed by the following components:

Components that consume Targets

Note
Connecting some components may not be sensible or components may require further configuration to make the connection work correctly. Refer to the linked documentation for more details.

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discovery.http

Usage

Arguments

Blocks

basic_auth block

authorization block

oauth2 block

tls_config block

Exported fields

Component health

Debug information

Debug metrics

Examples

Compatible components

Was this page helpful?

Related documentation

Feedback

discovery.http

Usage

Arguments

Blocks

basic_auth block

authorization block

oauth2 block

tls_config block

Exported fields

Component health

Debug information

Debug metrics

Examples

Compatible components

Was this page helpful?

Related documentation

Related resources from Grafana Labs