nats_stream

Subscribe to a NATS Stream subject. Joining a queue is optional and allows multiple clients of a subject to consume using queue semantics.

Common
Advanced

# Common config fields, showing default values
input:
  label: ""
  nats_stream:
    urls: [] # No default (required)
    cluster_id: "" # No default (required)
    client_id: ""
    queue: ""
    subject: ""
    durable_name: ""
    unsubscribe_on_close: false

# Advanced config fields, showing default values
input:
  label: ""
  nats_stream:
    urls: [] # No default (required)
    cluster_id: "" # No default (required)
    client_id: ""
    queue: ""
    subject: ""
    durable_name: ""
    unsubscribe_on_close: false
    start_from_oldest: true
    max_inflight: 1024
    ack_wait: 30s
    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)
      user_credentials_file: ./user.creds # No default (optional)
      user_jwt: "" # No default (optional)
      user_nkey_seed: "" # No default (optional)
    extract_tracing_map: root = @ # No default (optional)

[CAUTION] .Deprecation notice

The NATS Streaming Server is being deprecated. Critical bug fixes and security fixes will be applied until June of 2023. NATS-enabled applications requiring persistence should use JetStream.

Tracking and persisting offsets through a durable name is also optional and works with or without a queue. If a durable name is not provided then subjects are consumed from the most recently published message.

When a consumer closes its connection it unsubscribes, when all consumers of a durable queue do this the offsets are deleted. In order to avoid this you can stop the consumers from unsubscribing by setting the field unsubscribe_on_close to false.

Metadata

This input adds the following metadata fields to each message:

nats_stream_subject
nats_stream_sequence

You can access these metadata fields using function interpolation.

Authentication

There are several components within Redpanda Connect which uses NATS services. You will find that each of these components support optional advanced authentication parameters for NKeys and User Credentials.

See an in-depth tutorial.

NKey file

The NATS server can use these NKeys in several ways for authentication. The simplest is for the server to be configured with a list of known public keys and for the clients to respond to the challenge by signing it with its private NKey configured in the nkey_file field.

More details.

User credentials

NATS server supports decentralized authentication based on JSON Web Tokens (JWT). Clients need an user JWT and a corresponding NKey secret when connecting to a server which is configured to use this authentication scheme.

The user_credentials_file field should point to a file containing both the private key and the JWT and can be generated with the nsc tool.

Alternatively, the user_jwt field can contain a plain text JWT and the user_nkey_seedcan contain the plain text NKey Seed.

More details.

Fields

`urls`

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

Type: array

# Examples

urls:
  - nats://127.0.0.1:4222

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

`cluster_id`

The ID of the cluster to consume from.

Type: string

`client_id`

A client ID to connect as.

Type: string

Default: ""

`queue`

The queue to consume from.

Type: string

Default: ""

`subject`

A subject to consume from.

Type: string

Default: ""

`durable_name`

Preserve the state of your consumer under a durable name.

Type: string

Default: ""

`unsubscribe_on_close`

Whether the subscription should be destroyed when this client disconnects.

Type: bool

Default: false

`start_from_oldest`

If a position is not found for a queue, determines whether to consume from the oldest available message, otherwise messages are consumed from the latest.

Type: bool

Default: true

`max_inflight`

The maximum number of unprocessed messages to fetch at a given time.

Type: int

Default: 1024

`ack_wait`

An optional duration to specify at which a message that is yet to be acked will be automatically retried.

Type: string

Default: "30s"

`tls`

Custom TLS settings can be used to override system defaults.

Type: object

`tls.enabled`

Whether custom TLS settings are enabled.

Type: bool

Default: false

`tls.skip_cert_verify`

Whether to skip server side certificate verification.

Type: bool

Default: false

`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.

Type: bool

Default: false Requires version 3.45.0 or newer

`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.

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.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: array

Default: []

# Examples

client_certs:
  - cert: foo
    key: bar

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

`tls.client_certs[].cert`

A plain text certificate to use.

Type: string

Default: ""

`tls.client_certs[].key`

A plain text certificate key to use.

Type: string

Default: ""

`tls.client_certs[].cert_file`

The path of a certificate to use.

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.

Type: string

Default: ""

# Examples

password: foo

password: ${KEY_PASSWORD}

`auth`

Optional configuration of NATS authentication parameters.

Type: object

`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 an user JWT and corresponding NKey seed.

Type: string

# Examples

user_credentials_file: ./user.creds

`auth.user_jwt`

An optional plain text user JWT (given along with the corresponding user NKey Seed).

Type: string

`auth.user_nkey_seed`

An optional plain text user NKey Seed (given along with the corresponding user JWT).

Type: string

`extract_tracing_map`

EXPERIMENTAL: A Bloblang mapping that attempts to extract an object containing tracing propagation information, which will then be used as the root tracing span for the message. The specification of the extracted fields must match the format used by the service wide tracer.

Type: string

Requires version 4.23.0 or newer

# Examples

extract_tracing_map: root = @

extract_tracing_map: root = this.meta.span