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Reference

Configuration blocks

remotecfg

Open source

Public preview

remotecfg block

Public preview: This is a public preview component. Public preview components are subject to breaking changes, and may be replaced with equivalent functionality that cover the same use case. The stability.level flag must be set to public-preview or below to use the component.

remotecfg is an optional configuration block that enables Alloy to fetch and load the configuration from a remote endpoint. remotecfg is specified without a label and can only be provided once per configuration file.

The API definition for managing and fetching configuration that the remotecfg block uses is available under the Apache 2.0 license.

Example

remotecfg {
    url = "SERVICE_URL"
    basic_auth {
        username      = "USERNAME"
        password_file = "PASSWORD_FILE"
    }

    id             = constants.hostname
    attributes     = {"cluster" = "dev", "namespace" = "otlp-dev"}
    poll_frequency = "5m"
}

Arguments

The following arguments are supported:

Name	Type	Description	Default	Required
`url`	`string`	The address of the API to poll for configuration.	`""`	no
`id`	`string`	A self-reported ID.	`see below`	no
`attributes`	`map(string)`	A set of self-reported attributes.	`{}`	no
`poll_frequency`	`duration`	How often to poll the API for new configuration.	`"1m"`	no
`name`	`string`	A human-readable name for the collector.	`""`	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

If the url isn’t set, then the service block is a no-op.

If not set, the self-reported id that Alloy uses is a randomly generated, anonymous unique ID (UUID) that is stored as an alloy_seed.json file in the Alloy storage path so that it can persist across restarts. You can use the name field to set another human-friendly identifier for the specific Alloy instance.

The id and attributes fields are used in the periodic request sent to the remote endpoint so that the API can decide what configuration to serve.

The attribute map keys can include any custom value except the reserved prefix collector.. The reserved label prefix is for automatic system attributes. You can’t override this prefix.

collector.os: The operating system where Alloy is running.
collector.version: The version of Alloy.

The poll_frequency must be set to at least "10s".

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 remotecfg:

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 isn’t 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: