nats

Publish to an NATS subject.

  • Common

  • Advanced

# Common configuration fields, showing default values
output:
  label: ""
  nats:
    urls: [] # No default (required)
    subject: foo.bar.baz # No default (required)
    headers: {}
    metadata:
      include_prefixes: []
      include_patterns: []
    max_in_flight: 64
# All configuration fields, showing default values
output:
  label: ""
  nats:
    urls: [] # No default (required)
    subject: foo.bar.baz # No default (required)
    headers: {}
    metadata:
      include_prefixes: []
      include_patterns: []
    max_in_flight: 64
    tls:
      enabled: false
      skip_cert_verify: false
      enable_renegotiation: false
      root_cas: ""
      root_cas_file: ""
      client_certs: []
    auth:
      nkey_file: ./seed.nk # No default (optional)
      nkey: "" # No default (optional)
      user_credentials_file: ./user.creds # No default (optional)
      user_jwt: "" # No default (optional)
      user_nkey_seed: "" # No default (optional)
    inject_tracing_map: meta = @.merge(this) # No default (optional)

This output interpolates functions within the subject field. For a full list of functions, see configuration:interpolation.adoc#bloblang-queries.

Connection name

When monitoring and managing a production NATS system, it is often useful to know which connection a message was sent or received from. To achieve this, set the connection name option when creating a NATS connection. Redpanda Connect can then automatically set the connection name to the NATS component label, so that monitoring tools between NATS and Redpanda Connect can stay in sync.

Authentication

A number of Redpanda Connect components use NATS services. Each of these components support optional, advanced authentication parameters for NKeys and user credentials.

For an in-depth guide, see the NATS documentation.

NKeys

NATS server can use NKeys in several ways for authentication. The simplest approach is to configure the server with a list of user’s public keys. The server can then generate a challenge for each connection request from a client, and the client must respond to the challenge by signing it with its private NKey, configured in the nkey_file or nkey field.

For more details, see the NATS documentation.

User credentials

NATS server also supports decentralized authentication based on JSON Web Tokens (JWTs). When a server is configured to use this authentication scheme, clients need a user JWT and a corresponding NKey secret to connect.

You can use either of the following methods to supply the user JWT and NKey secret:

  • In the user_credentials_file field, enter the path to a file containing both the private key and the JWT. You can generate the file using the nsc tool.

  • In the user_jwt field, enter a plain text JWT, and in the user_nkey_seed field, enter the plain text NKey seed or private key.

For more details about authentication using JWTs, see the NATS documentation.

Fields

auth

Optional configuration of NATS authentication parameters.

Type: object

auth.nkey

Your NKey seed or private key.

This field contains sensitive information that usually shouldn’t be added to a configuration directly. For more information, see Secrets.

Requires version 4.38.0 or later.

Type: string

# Examples:
nkey: UDXU4RCSJNZOIQHZNWXHXORDPRTGNJAHAHFRGZNEEJCPQTT2M7NLCNF4

auth.nkey_file

An optional file containing a NKey seed.

Type: string

# Examples:
nkey_file: ./seed.nk

auth.user_credentials_file

An optional file containing user credentials which consist of a user JWT and corresponding NKey seed.

Type: string

# Examples:
user_credentials_file: ./user.creds

auth.user_jwt

An optional plain text user JWT to use along with the corresponding user NKey seed.

This field contains sensitive information that usually shouldn’t be added to a configuration directly. For more information, see Secrets.

Type: string

auth.user_nkey_seed

An optional plain text user NKey seed to use along with the corresponding user JWT.

This field contains sensitive information that usually shouldn’t be added to a configuration directly. For more information, see Secrets.

Type: string

headers

Explicit message headers to add to messages. This field supports interpolation functions.

Type: string

Default: {}

# Examples:
headers:
  Content-Type: application/json
  Timestamp: ${!meta("Timestamp")}

inject_tracing_map

EXPERIMENTAL: A Bloblang mapping used to inject an object containing tracing propagation information into outbound messages. The specification of the injected fields will match the format used by the service wide tracer.

Requires version 4.23.0 or later.

Type: string

# Examples:
inject_tracing_map: meta = @.merge(this)
inject_tracing_map: root.meta.span = this

max_in_flight

The maximum number of messages to have in flight at a given time. Increase this to improve throughput.

Type: int

Default: 64

max_reconnects

The maximum number of times to attempt to reconnect to the server. If negative, it will never stop trying to reconnect.

Type: int

metadata

Determine which (if any) metadata values should be added to messages as headers.

Type: object

metadata.include_patterns[]

Provide a list of explicit metadata key regular expression (re2) patterns to match against.

Type: array

Default: []

# Examples:
include_patterns:
  - .*

  - _timestamp_unix$

metadata.include_prefixes[]

Provide a list of explicit metadata key prefixes to match against.

Type: array

Default: []

# Examples:
include_prefixes:
  - foo_
  - bar_

  - kafka_

  - content-

subject

The subject to publish to. This field supports interpolation functions.

Type: string

# Examples:
subject: foo.bar.baz

tls

Custom TLS settings can be used to override system defaults.

Type: object

tls.client_certs[]

A list of client certificates to use. For each certificate either the fields cert and key, or cert_file and key_file should be specified, but not both.

Type: object

Default: []

# Examples:
client_certs:
  - cert: foo
    key: bar

  - cert_file: ./example.pem
    key_file: ./example.key

tls.client_certs[].cert

A plain text certificate to use.

Type: string

Default: ""

tls.client_certs[].cert_file

The path of a certificate to use.

Type: string

Default: ""

tls.client_certs[].key

A plain text certificate key to use.

This field contains sensitive information that usually shouldn’t be added to a configuration directly. For more information, see Secrets.

Type: string

Default: ""

tls.client_certs[].key_file

The path of a certificate key to use.

Type: string

Default: ""

tls.client_certs[].password

A plain text password for when the private key is password encrypted in PKCS#1 or PKCS#8 format. The obsolete pbeWithMD5AndDES-CBC algorithm is not supported for the PKCS#8 format.

Because the obsolete pbeWithMD5AndDES-CBC algorithm does not authenticate the ciphertext, it is vulnerable to padding oracle attacks that can let an attacker recover the plaintext.

This field contains sensitive information that usually shouldn’t be added to a configuration directly. For more information, see Secrets.

Type: string

Default: ""

# Examples:
password: foo
password: ${KEY_PASSWORD}

tls.enable_renegotiation

Whether to allow the remote server to repeatedly request renegotiation. Enable this option if you’re seeing the error message local error: tls: no renegotiation.

Requires version 3.45.0 or later.

Type: bool

Default: false

tls.enabled

Whether custom TLS settings are enabled.

Type: bool

Default: false

tls.root_cas

An optional root certificate authority to use. This is a string, representing a certificate chain from the parent trusted root certificate, to possible intermediate signing certificates, to the host certificate.

This field contains sensitive information that usually shouldn’t be added to a configuration directly. For more information, see Secrets.

Type: string

Default: ""

# Examples:
root_cas: |-
  -----BEGIN CERTIFICATE-----
  ...
  -----END CERTIFICATE-----

tls.root_cas_file

An optional path of a root certificate authority file to use. This is a file, often with a .pem extension, containing a certificate chain from the parent trusted root certificate, to possible intermediate signing certificates, to the host certificate.

Type: string

Default: ""

# Examples:
root_cas_file: ./root_cas.pem

tls.skip_cert_verify

Whether to skip server side certificate verification.

Type: bool

Default: false

urls[]

A list of URLs to connect to. If a list item contains commas, it will be expanded into multiple URLs.

Type: array

# Examples:
urls:
  - "nats://127.0.0.1:4222"

  - "nats://username:password@127.0.0.1:4222"