loki.source.docker
loki.source.docker
reads log entries from Docker containers and forwards them to other loki.*
components. Each component can read from a single Docker daemon.
You can specify multiple loki.source.docker
components by giving them different labels.
Usage
loki.source.docker "LABEL" {
host = HOST
targets = TARGET_LIST
forward_to = RECEIVER_LIST
}
Arguments
The component starts a new reader for each of the given targets
and fans out log entries to the list of receivers passed in forward_to
.
You can use the following arguments with loki.source.docker
:
Blocks
You can use the following blocks with loki.source.docker
:
The > symbol indicates deeper levels of nesting.
For example, client
> basic_auth
refers to an basic_auth
block defined inside a client
block.
These blocks are only applicable when connecting to a Docker daemon over HTTP or HTTPS and has no effect when connecting via a unix:///
socket
client
The client
block configures settings used to connect to HTTP(S) Docker daemons.
bearer_token
, bearer_token_file
, basic_auth
, authorization
, and oauth2
are mutually exclusive, and only one can be provided inside of a http_client_config
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.
authorization
The authorization
block configures custom authorization to use for the Docker daemon.
credential
and credentials_file
are mutually exclusive, and only one can be provided inside an authorization
block.
basic_auth
The basic_auth
block configures basic authentication for HTTP(S) Docker daemons.
password
and password_file
are mutually exclusive, and only one can be provided inside a basic_auth
block.
oauth2
The oauth2
block configures OAuth 2.0 authorization to use for the Docker daemon.
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_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.
tls_config
The tls_config
block configures TLS settings for connecting to HTTPS Docker daemons.
The following pairs of arguments are mutually exclusive and can’t both be set simultaneously:
ca_pem
andca_file
cert_pem
andcert_file
key_pem
andkey_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:
"TLS10"
(TLS 1.0)"TLS11"
(TLS 1.1)"TLS12"
(TLS 1.2)"TLS13"
(TLS 1.3)
Exported fields
loki.source.docker
doesn’t export any fields.
Component health
loki.source.docker
is only reported as unhealthy if given an invalid configuration.
Debug information
loki.source.docker
exposes some debug information per target:
- Whether the target is ready to tail entries.
- The labels associated with the target.
- The most recent time a log line was read.
Debug metrics
loki_source_docker_target_entries_total
(gauge): Total number of successful entries sent to the Docker target.loki_source_docker_target_parsing_errors_total
(gauge): Total number of parsing errors while receiving Docker messages.
Component behavior
The component uses its data path, a directory named after the domain’s fully qualified name, to store its positions file.
The positions file is used to store read offsets, so that if a component or Alloy restarts, loki.source.docker
can pick up tailing from the same spot.
If the target’s argument contains multiple entries with the same container ID, for example, as a result of discovery.docker
picking up multiple exposed ports or networks, loki.source.docker
deduplicates them, and only keeps the first of each container ID instances, based on the __meta_docker_container_id
label.
As such, the Docker daemon is queried for each container ID only once, and only one target is available in the component’s debug info.
Example
This example collects log entries from the files specified in the targets
argument and forwards them to a loki.write
component to be written to Loki.
discovery.docker "linux" {
host = "unix:///var/run/docker.sock"
}
loki.source.docker "default" {
host = "unix:///var/run/docker.sock"
targets = discovery.docker.linux.targets
labels = {"app" = "docker"}
forward_to = [loki.write.local.receiver]
}
loki.write "local" {
endpoint {
url = "loki:3100/loki/api/v1/push"
}
}
Compatible components
loki.source.docker
can accept arguments from the following components:
- Components that export Targets
- Components that export Loki
LogsReceiver
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.