NATS sink

Configuration

Example configurations

{
  "sinks": {
    "my_sink_id": {
      "type": "nats",
      "inputs": [
        "my-source-or-transform-id"
      ],
      "subject": "{{ host }}",
      "url": "nats://demo.nats.io"
    }
  }
}

[sinks.my_sink_id]
type = "nats"
inputs = [ "my-source-or-transform-id" ]
subject = "{{ host }}"
url = "nats://demo.nats.io"

sinks:
  my_sink_id:
    type: nats
    inputs:
      - my-source-or-transform-id
    subject: "{{ host }}"
    url: nats://demo.nats.io

{
  "sinks": {
    "my_sink_id": {
      "type": "nats",
      "inputs": [
        "my-source-or-transform-id"
      ],
      "connection_name": "vector",
      "subject": "{{ host }}",
      "url": "nats://demo.nats.io"
    }
  }
}

[sinks.my_sink_id]
type = "nats"
inputs = [ "my-source-or-transform-id" ]
connection_name = "vector"
subject = "{{ host }}"
url = "nats://demo.nats.io"

sinks:
  my_sink_id:
    type: nats
    inputs:
      - my-source-or-transform-id
    connection_name: vector
    subject: "{{ host }}"
    url: nats://demo.nats.io

acknowledgements

optional object

Controls how acknowledgements are handled for this sink.

See End-to-end Acknowledgements for more information on how event acknowledgement is handled.

acknowledgements.enabled

optional bool

Whether or not end-to-end acknowledgements are enabled.

When enabled for a sink, any source connected to that sink, where the source supports end-to-end acknowledgements as well, waits for events to be acknowledged by the sink before acknowledging them at the source.

Enabling or disabling acknowledgements at the sink level takes precedence over any global acknowledgements configuration.

auth

optional object

Configuration of the authentication strategy when interacting with NATS.

auth.credentials_file

required object

Credentials file configuration.

Relevant when: strategy = "credentials_file"

auth.credentials_file.path

required string literal

Path to credentials file.

Examples

"/etc/nats/nats.creds"

auth.nkey

required object

NKeys configuration.

Relevant when: strategy = "nkey"

auth.nkey.nkey

required string literal

User.

Conceptually, this is equivalent to a public key.

auth.nkey.seed

required string literal

Seed.

Conceptually, this is equivalent to a private key.

auth.strategy

required string literal enum

The strategy used to authenticate with the NATS server.

More information on NATS authentication, and the various authentication strategies, can be found in the NATS documentation. For TLS client certificate authentication specifically, see the tls settings.

Enum options

Option	Description
`credentials_file`	Credentials file authentication. (JWT-based)
`nkey`	NKey authentication.
`token`	Token authentication.
`user_password`	Username/password authentication.

Examples

"credentials_file"

"nkey"

"token"

"user_password"

auth.token

required object

Token configuration.

Relevant when: strategy = "token"

auth.token.value

required string literal

Token.

auth.user_password

required object

Username and password configuration.

Relevant when: strategy = "user_password"

auth.user_password.password

required string literal

Password.

auth.user_password.user

required string literal

Username.

buffer

optional object

Configures the buffering behavior for this sink.

More information about the individual buffer types, and buffer behavior, can be found in the Buffering Model section.

buffer.max_events

optional uint

The maximum number of events allowed in the buffer.

Relevant when: type = "memory"

default: 500

buffer.max_size

required uint

The maximum size of the buffer on disk.

Must be at least ~256 megabytes (268435488 bytes).

Relevant when: type = "disk"

buffer.type

optional string literal enum

The type of buffer to use.

Enum options

Option Description

Option	Description
`disk`	Events are buffered on disk. This is less performant, but more durable. Data that has been synchronized to disk will not be lost if Vector is restarted forcefully or crashes. Data is synchronized to disk every 500ms.
`memory`	Events are buffered in memory. This is more performant, but less durable. Data will be lost if Vector is restarted forcefully or crashes.

disk

Events are buffered on disk.

This is less performant, but more durable. Data that has been synchronized to disk will not be lost if Vector is restarted forcefully or crashes.

Data is synchronized to disk every 500ms.

memory

Events are buffered in memory.

This is more performant, but less durable. Data will be lost if Vector is restarted forcefully or crashes.

default: memory

buffer.when_full

optional string literal enum

Event handling behavior when a buffer is full.

Enum options

Option Description

Option	Description
`block`	Wait for free space in the buffer. This applies backpressure up the topology, signalling that sources should slow down the acceptance/consumption of events. This means that while no data is lost, data will pile up at the edge.
`drop_newest`	Drops the event instead of waiting for free space in buffer. The event will be intentionally dropped. This mode is typically used when performance is the highest priority, and it is preferable to temporarily lose events rather than cause a slowdown in the acceptance/consumption of events.

block

Wait for free space in the buffer.

This applies backpressure up the topology, signalling that sources should slow down the acceptance/consumption of events. This means that while no data is lost, data will pile up at the edge.

drop_newest

Drops the event instead of waiting for free space in buffer.

The event will be intentionally dropped. This mode is typically used when performance is the highest priority, and it is preferable to temporarily lose events rather than cause a slowdown in the acceptance/consumption of events.

default: block

connection_name

optional string literal

A NATS name assigned to the NATS connection.

Examples

"foo"

default: vector

encoding

required object

Configures how events are encoded into raw bytes.

encoding.avro

required object

Apache Avro-specific encoder options.

Relevant when: codec = "avro"

encoding.avro.schema

required string literal

The Avro schema.

Examples

"{ \"type\": \"record\", \"name\": \"log\", \"fields\": [{ \"name\": \"message\", \"type\": \"string\" }] }"

encoding.codec

required string literal enum

The codec to use for encoding events.

Enum options

Option	Description
`avro`	Encodes an event as an Apache Avro message.
`csv`	Encodes an event as a CSV message. This codec must be configured with fields to encode.
`gelf`	Encodes an event as a GELF message.
`json`	Encodes an event as JSON.
`logfmt`	Encodes an event as a logfmt message.
`native`	Encodes an event in the native Protocol Buffers format. This codec is experimental.
`native_json`	Encodes an event in the native JSON format. This codec is experimental.
`raw_message`	No encoding. This encoding uses the `message` field of a log event. Be careful if you are modifying your log events (for example, by using a `remap` transform) and removing the message field while doing additional parsing on it, as this could lead to the encoding emitting empty strings for the given event.
`text`	Plain text encoding. This encoding uses the `message` field of a log event. For metrics, it uses an encoding that resembles the Prometheus export format. Be careful if you are modifying your log events (for example, by using a `remap` transform) and removing the message field while doing additional parsing on it, as this could lead to the encoding emitting empty strings for the given event.

Examples

"avro"

"csv"

"gelf"

"json"

"logfmt"

"native"

"native_json"

"raw_message"

"text"

encoding.csv

required object

The CSV Serializer Options.

Relevant when: codec = "csv"

encoding.csv.capacity

optional uint

Set the capacity (in bytes) of the internal buffer used in the CSV writer. This defaults to a reasonable setting.

default: 8192

encoding.csv.delimiter

optional uint

The field delimiter to use when writing CSV.

default: 44

encoding.csv.double_quote

optional bool

Enable double quote escapes.

This is enabled by default, but it may be disabled. When disabled, quotes in field data are escaped instead of doubled.

default: true

encoding.csv.escape

optional uint

The escape character to use when writing CSV.

In some variants of CSV, quotes are escaped using a special escape character like \ (instead of escaping quotes by doubling them).

To use this, double_quotes needs to be disabled as well otherwise it is ignored.

default: 34

encoding.csv.fields

required [string]

Configures the fields that will be encoded, as well as the order in which they appear in the output.

If a field is not present in the event, the output will be an empty string.

Values of type Array, Object, and Regex are not supported and the output will be an empty string.

encoding.csv.quote

optional uint

The quote character to use when writing CSV.

default: 34

encoding.csv.quote_style

optional string literal enum

The quoting style to use when writing CSV data.

Enum options

Option	Description
`always`	Always puts quotes around every field.
`necessary`	Puts quotes around fields only when necessary. They are necessary when fields contain a quote, delimiter, or record terminator. Quotes are also necessary when writing an empty record (which is indistinguishable from a record with one empty field).
`never`	Never writes quotes, even if it produces invalid CSV data.
`non_numeric`	Puts quotes around all fields that are non-numeric. Namely, when writing a field that does not parse as a valid float or integer, then quotes are used even if they aren’t strictly necessary.

default: necessary

encoding.except_fields

optional [string]

List of fields that are excluded from the encoded event.

encoding.metric_tag_values

optional string literal enum

Controls how metric tag values are encoded.

When set to single, only the last non-bare value of tags are displayed with the metric. When set to full, all metric tags are exposed as separate assignments.

Relevant when: codec = "json" or codec = "text"

Enum options

Option	Description
`full`	All tags are exposed as arrays of either string or null values.
`single`	Tag values are exposed as single strings, the same as they were before this config option. Tags with multiple values show the last assigned value, and null values are ignored.

default: single

encoding.only_fields

optional [string]

List of fields that are included in the encoded event.

encoding.timestamp_format

optional string literal enum

Format used for timestamp fields.

Enum options

Option	Description
`rfc3339`	Represent the timestamp as a RFC 3339 timestamp.
`unix`	Represent the timestamp as a Unix timestamp.

healthcheck

optional object

Healthcheck configuration.

healthcheck.enabled

optional bool

Whether or not to check the health of the sink when Vector starts up.

default: true

inputs

required [string]

A list of upstream source or transform IDs.

Wildcards (*) are supported.

See configuration for more info.

Array string literal

Examples

[
  "my-source-or-transform-id",
  "prefix-*"
]

request

optional object

Middleware settings for outbound requests.

Various settings can be configured, such as concurrency and rate limits, timeouts, etc.

request.adaptive_concurrency

optional object

Configuration of adaptive concurrency parameters.

These parameters typically do not require changes from the default, and incorrect values can lead to meta-stable or unstable performance and sink behavior. Proceed with caution.

request.adaptive_concurrency.decrease_ratio

optional float

The fraction of the current value to set the new concurrency limit when decreasing the limit.

Valid values are greater than 0 and less than 1. Smaller values cause the algorithm to scale back rapidly when latency increases.

Note that the new limit is rounded down after applying this ratio.

default: 0.9

request.adaptive_concurrency.ewma_alpha

optional float

The weighting of new measurements compared to older measurements.

Valid values are greater than 0 and less than 1.

ARC uses an exponentially weighted moving average (EWMA) of past RTT measurements as a reference to compare with the current RTT. Smaller values cause this reference to adjust more slowly, which may be useful if a service has unusually high response variability.

default: 0.4

request.adaptive_concurrency.initial_concurrency

optional uint

The initial concurrency limit to use. If not specified, the initial limit will be 1 (no concurrency).

It is recommended to set this value to your service’s average limit if you’re seeing that it takes a long time to ramp up adaptive concurrency after a restart. You can find this value by looking at the adaptive_concurrency_limit metric.

default: 1

request.adaptive_concurrency.rtt_deviation_scale

optional float

Scale of RTT deviations which are not considered anomalous.

Valid values are greater than or equal to 0, and we expect reasonable values to range from 1.0 to 3.0.

When calculating the past RTT average, we also compute a secondary “deviation” value that indicates how variable those values are. We use that deviation when comparing the past RTT average to the current measurements, so we can ignore increases in RTT that are within an expected range. This factor is used to scale up the deviation to an appropriate range. Larger values cause the algorithm to ignore larger increases in the RTT.

default: 2.5

request.concurrency

optional string literal enum uint

Configuration for outbound request concurrency.

This can be set either to one of the below enum values or to a positive integer, which denotes a fixed concurrency limit.

Enum options

Option Description

adaptive Concurrency will be managed by Vector’s Adaptive Request Concurrency feature.

Option	Description
`adaptive`	Concurrency will be managed by Vector’s Adaptive Request Concurrency feature.
`none`	A fixed concurrency of 1. Only one request can be outstanding at any given time.

none

A fixed concurrency of 1.

Only one request can be outstanding at any given time.

default: adaptive

request.rate_limit_duration_secs

optional uint

The time window used for the rate_limit_num option.

default: 1 (seconds)

request.rate_limit_num

optional uint

The maximum number of requests allowed within the rate_limit_duration_secs time window.

default: 9.223372036854776e+18 (requests)

request.retry_attempts

optional uint

The maximum number of retries to make for failed requests.

The default, for all intents and purposes, represents an infinite number of retries.

default: 9.223372036854776e+18 (retries)

request.retry_initial_backoff_secs

optional uint

The amount of time to wait before attempting the first retry for a failed request.

After the first retry has failed, the fibonacci sequence is used to select future backoffs.

default: 1 (seconds)

request.retry_max_duration_secs

optional uint

The maximum amount of time to wait between retries.

default: 3600 (seconds)

request.timeout_secs

optional uint

The time a request can take before being aborted.

Datadog highly recommends that you do not lower this value below the service’s internal timeout, as this could create orphaned requests, pile on retries, and result in duplicate data downstream.

default: 60 (seconds)

subject

required string template

The NATS subject to publish messages to.

Note: This parameter supports Vector's template syntax, which enables you to use dynamic per-event values.

Examples

"{{ host }}"

"foo"

"time.us.east"

"time.*.east"

"time.\u003e"

"\u003e"

tls

optional object

Configures the TLS options for incoming/outgoing connections.

tls.alpn_protocols

optional [string]

Sets the list of supported ALPN protocols.

Declare the supported ALPN protocols, which are used during negotiation with peer. They are prioritized in the order that they are defined.

tls.ca_file

optional string literal

Absolute path to an additional CA certificate file.

The certificate must be in the DER or PEM (X.509) format. Additionally, the certificate can be provided as an inline string in PEM format.

Examples

"/path/to/certificate_authority.crt"

tls.crt_file

optional string literal

Absolute path to a certificate file used to identify this server.

The certificate must be in DER, PEM (X.509), or PKCS#12 format. Additionally, the certificate can be provided as an inline string in PEM format.

If this is set, and is not a PKCS#12 archive, key_file must also be set.

Examples

"/path/to/host_certificate.crt"

tls.enabled

optional bool

Whether or not to require TLS for incoming or outgoing connections.

When enabled and used for incoming connections, an identity certificate is also required. See tls.crt_file for more information.

tls.key_file

optional string literal

Absolute path to a private key file used to identify this server.

The key must be in DER or PEM (PKCS#8) format. Additionally, the key can be provided as an inline string in PEM format.

Examples

"/path/to/host_certificate.key"

tls.key_pass

optional string literal

Passphrase used to unlock the encrypted key file.

This has no effect unless key_file is set.

Examples

"${KEY_PASS_ENV_VAR}"

"PassWord1"

tls.verify_certificate

optional bool

Enables certificate verification.

If enabled, certificates must not be expired and must be issued by a trusted issuer. This verification operates in a hierarchical manner, checking that the leaf certificate (the certificate presented by the client/server) is not only valid, but that the issuer of that certificate is also valid, and so on until the verification process reaches a root certificate.

Relevant for both incoming and outgoing connections.

Do NOT set this to false unless you understand the risks of not verifying the validity of certificates.

tls.verify_hostname

optional bool

Enables hostname verification.

If enabled, the hostname used to connect to the remote host must be present in the TLS certificate presented by the remote host, either as the Common Name or as an entry in the Subject Alternative Name extension.

Only relevant for outgoing connections.

Do NOT set this to false unless you understand the risks of not verifying the remote hostname.

url

required string literal

The NATS URL to connect to.

The URL must take the form of nats://server:port. If the port is not specified it defaults to 4222.

Examples

"nats://demo.nats.io"

"nats://127.0.0.1:4242"

Telemetry

Metrics

link

buffer_byte_size

gauge

The number of bytes current in the buffer.

component_id

The Vector component ID.

component_kind

The Vector component kind.

component_name

Deprecated, use component_id instead. The value is the same as component_id.

component_type

The Vector component type.

host optional

The hostname of the system Vector is running on.

pid optional

The process ID of the Vector instance.

buffer_discarded_events_total

counter

The number of events dropped by this non-blocking buffer.

component_id

The Vector component ID.

component_kind

The Vector component kind.

component_name

Deprecated, use component_id instead. The value is the same as component_id.

component_type

The Vector component type.

host optional

The hostname of the system Vector is running on.

pid optional

The process ID of the Vector instance.

buffer_events

gauge

The number of events currently in the buffer.

component_id

The Vector component ID.

component_kind

The Vector component kind.

component_name

Deprecated, use component_id instead. The value is the same as component_id.

component_type

The Vector component type.

host optional

The hostname of the system Vector is running on.

pid optional

The process ID of the Vector instance.

buffer_received_event_bytes_total

counter

The number of bytes received by this buffer.

component_id

The Vector component ID.

component_kind

The Vector component kind.

component_name

Deprecated, use component_id instead. The value is the same as component_id.

component_type

The Vector component type.

host optional

The hostname of the system Vector is running on.

pid optional

The process ID of the Vector instance.

buffer_received_events_total

counter

The number of events received by this buffer.

component_id

The Vector component ID.

component_kind

The Vector component kind.

component_name

Deprecated, use component_id instead. The value is the same as component_id.

component_type

The Vector component type.

host optional

The hostname of the system Vector is running on.

pid optional

The process ID of the Vector instance.

buffer_sent_event_bytes_total

counter

The number of bytes sent by this buffer.

component_id

The Vector component ID.

component_kind

The Vector component kind.

component_name

Deprecated, use component_id instead. The value is the same as component_id.

component_type

The Vector component type.

host optional

The hostname of the system Vector is running on.

pid optional

The process ID of the Vector instance.

buffer_sent_events_total

counter

The number of events sent by this buffer.

component_id

The Vector component ID.

component_kind

The Vector component kind.

component_name

Deprecated, use component_id instead. The value is the same as component_id.

component_type

The Vector component type.

host optional

The hostname of the system Vector is running on.

pid optional

The process ID of the Vector instance.

component_discarded_events_total

counter

The number of events dropped by this component.

component_id

The Vector component ID.

component_kind

The Vector component kind.

component_name

Deprecated, use component_id instead. The value is the same as component_id.

component_type

The Vector component type.

host optional

The hostname of the system Vector is running on.

intentional

True if the events were discarded intentionally, like a filter transform, or false if due to an error.

pid optional

The process ID of the Vector instance.

component_errors_total

counter

The total number of errors encountered by this component.

component_id

The Vector component ID.

component_kind

The Vector component kind.

component_name

Deprecated, use component_id instead. The value is the same as component_id.

component_type

The Vector component type.

error_type

The type of the error

host optional

The hostname of the system Vector is running on.

pid optional

The process ID of the Vector instance.

stage

The stage within the component at which the error occurred.

component_received_event_bytes_total

counter

The number of event bytes accepted by this component either from tagged origins like file and uri, or cumulatively from other origins.

component_id

The Vector component ID.

component_kind

The Vector component kind.

component_name

Deprecated, use component_id instead. The value is the same as component_id.

component_type

The Vector component type.

container_name optional

The name of the container from which the data originated.

file optional

The file from which the data originated.

host optional

The hostname of the system Vector is running on.

mode optional

The connection mode used by the component.

peer_addr optional

The IP from which the data originated.

peer_path optional

The pathname from which the data originated.

pid optional

The process ID of the Vector instance.

pod_name optional

The name of the pod from which the data originated.

uri optional

The sanitized URI from which the data originated.

component_received_events_count

histogram

A histogram of the number of events passed in each internal batch in Vector’s internal topology.

Note that this is separate than sink-level batching. It is mostly useful for low level debugging performance issues in Vector due to small internal batches.

component_id

The Vector component ID.

component_kind

The Vector component kind.

component_name

Deprecated, use component_id instead. The value is the same as component_id.

component_type

The Vector component type.

container_name optional

The name of the container from which the data originated.

file optional

The file from which the data originated.

host optional

The hostname of the system Vector is running on.

mode optional

The connection mode used by the component.

peer_addr optional

The IP from which the data originated.

peer_path optional

The pathname from which the data originated.

pid optional

The process ID of the Vector instance.

pod_name optional

The name of the pod from which the data originated.

uri optional

The sanitized URI from which the data originated.

component_received_events_total

counter

The number of events accepted by this component either from tagged origins like file and uri, or cumulatively from other origins.

component_id

The Vector component ID.

component_kind

The Vector component kind.

component_name

Deprecated, use component_id instead. The value is the same as component_id.

component_type

The Vector component type.

container_name optional

The name of the container from which the data originated.

file optional

The file from which the data originated.

host optional

The hostname of the system Vector is running on.

mode optional

The connection mode used by the component.

peer_addr optional

The IP from which the data originated.

peer_path optional

The pathname from which the data originated.

pid optional

The process ID of the Vector instance.

pod_name optional

The name of the pod from which the data originated.

uri optional

The sanitized URI from which the data originated.

component_sent_bytes_total

counter

The number of raw bytes sent by this component to destination sinks.

component_id

The Vector component ID.

component_kind

The Vector component kind.

component_name

Deprecated, use component_id instead. The value is the same as component_id.

component_type

The Vector component type.

endpoint optional

The endpoint to which the bytes were sent. For HTTP, this will be the host and path only, excluding the query string.

file optional

The absolute path of the destination file.

host optional

The hostname of the system Vector is running on.

pid optional

The process ID of the Vector instance.

protocol

The protocol used to send the bytes.

region optional

The AWS region name to which the bytes were sent. In some configurations, this may be a literal hostname.

component_sent_event_bytes_total

counter

The total number of event bytes emitted by this component.

component_id

The Vector component ID.

component_kind

The Vector component kind.

component_name

Deprecated, use component_id instead. The value is the same as component_id.

component_type

The Vector component type.

host optional

The hostname of the system Vector is running on.

output optional

The specific output of the component.

pid optional

The process ID of the Vector instance.

component_sent_events_total

counter

The total number of events emitted by this component.

component_id

The Vector component ID.

component_kind

The Vector component kind.

component_name

Deprecated, use component_id instead. The value is the same as component_id.

component_type

The Vector component type.

host optional

The hostname of the system Vector is running on.

output optional

The specific output of the component.

pid optional

The process ID of the Vector instance.

send_errors_total

counter

The total number of errors sending messages.

component_id

The Vector component ID.

component_kind

The Vector component kind.

component_name

Deprecated, use component_id instead. The value is the same as component_id.

component_type

The Vector component type.

host optional

The hostname of the system Vector is running on.

pid optional

The process ID of the Vector instance.

utilization

gauge

A ratio from 0 to 1 of the load on a component. A value of 0 would indicate a completely idle component that is simply waiting for input. A value of 1 would indicate a that is never idle. This value is updated every 5 seconds.

component_id

The Vector component ID.

component_kind

The Vector component kind.

component_name

Deprecated, use component_id instead. The value is the same as component_id.

component_type

The Vector component type.

host optional

The hostname of the system Vector is running on.

pid optional

The process ID of the Vector instance.

How it works

Health checks

Health checks ensure that the downstream service is accessible and ready to accept data. This check is performed upon sink initialization. If the health check fails an error will be logged and Vector will proceed to start.

Require health checks

If you’d like to exit immediately upon a health check failure, you can pass the --require-healthy flag:

vector --config /etc/vector/vector.yaml --require-healthy

Disable health checks

If you’d like to disable health checks for this sink you can set the healthcheck option to false.

nats.rs

The nats source/sink uses nats.rs under the hood.

State

This component is stateless, meaning its behavior is consistent across each input.

Transport Layer Security (TLS)

Vector uses OpenSSL for TLS protocols due to OpenSSL’s maturity. You can enable and adjust TLS behavior via the tls.* options and/or via an OpenSSL configuration file. The file location defaults to /usr/local/ssl/openssl.cnf or can be specified with the OPENSSL_CONF environment variable.