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nats_jetstream

Reads messages from NATS JetStream subjects.

Introduced in version 3.46.0.

Common
Advanced

input:
  label: ""
  nats_jetstream:
    urls: [] # No default (required)
    queue: "" # No default (optional)
    subject: "" # No default (optional)
    durable: "" # No default (optional)
    stream: "" # No default (optional)
    bind: false # No default (optional)
    deliver: all

input:
  label: ""
  nats_jetstream:
    urls: [] # No default (required)
    max_reconnects: 0 # No default (optional)
    queue: "" # No default (optional)
    subject: "" # No default (optional)
    durable: "" # No default (optional)
    stream: "" # No default (optional)
    bind: false # No default (optional)
    create_stream: false
    deliver: all
    ack_wait: 30s
    max_ack_pending: 1024
    tls:
      enabled: false
      skip_cert_verify: false
      enable_renegotiation: false
      root_cas: ""
      root_cas_file: ""
      client_certs: []
    tls_handshake_first: false
    auth:
      nkey_file: "" # No default (optional)
      nkey: "" # No default (optional)
      user_credentials_file: "" # No default (optional)
      user_jwt: "" # No default (optional)
      user_nkey_seed: "" # No default (optional)
      user: "" # No default (optional)
      password: "" # No default (optional)
      token: "" # No default (optional)
    extract_tracing_map: "" # No default (optional)

Consume mirrored streams

When a stream being consumed is mirrored in a different JetStream domain, the stream cannot be resolved from the subject name alone. You must specify the stream name as well as the subject (if applicable).

Metadata

This input adds the following metadata fields to each message:

nats_subject
nats_sequence_stream
nats_sequence_consumer
nats_num_delivered
nats_num_pending
nats_domain
nats_timestamp_unix_nano
nats_consumer

You can access these metadata fields using function interpolation.

Fields

`ack_wait`

The maximum amount of time NATS server should wait for an ack from consumer.

Type: string

Default: 30s

# Examples:
ack_wait: 100ms

# ---

ack_wait: 5m

`auth`

Optional configuration of NATS authentication parameters.

Type: object

`auth.nkey`

Your NKey seed (private key) for NATS authentication. NKeys provide cryptographic authentication without passwords.

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.password`

An optional plain text password (given along with the corresponding user name).

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

Requires version 4.84.0 or later.

Type: string

`auth.token`

An optional plain text token.

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

Requires version 4.84.0 or later.

Type: string

`auth.user`

An optional plain text user name (given along with the corresponding user password).

Requires version 4.84.0 or later.

Type: string

`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 plaintext 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.

Requires version 4.16.0 or later.

Type: string

`auth.user_nkey_seed`

An optional plaintext 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.

Requires version 4.16.0 or later.

Type: string

`bind`

Indicates that the subscription should use an existing consumer.

Type: bool

`create_stream`

Whether to automatically create the stream if it doesn’t exist (requires the stream field to be set).

Requires version 4.84.0 or later.

Type: bool

Default: false

`deliver`

Determines which messages to deliver when consuming without a durable subscriber.

Type: string

Default: all

Option Summary

Option	Summary
`all`	Deliver all available messages.
`last`	Deliver starting with the last published messages.
`last_per_subject`	Deliver starting with the last published message per subject.
`new`	Deliver starting from now, not taking into account any previous messages.

all

Deliver all available messages.

last

Deliver starting with the last published messages.

last_per_subject

Deliver starting with the last published message per subject.

new

Deliver starting from now, not taking into account any previous messages.

`durable`

Preserve the state of your consumer under a durable name.

Type: string

`extract_tracing_map`

EXPERIMENTAL: A Bloblang mapping that attempts to extract an object containing tracing propagation information, which is then 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.

Requires version 4.23.0 or later.

Type: string

# Examples:
extract_tracing_map: root = @

# ---

extract_tracing_map: root = this.meta.span

`max_ack_pending`

The maximum number of outstanding acks to be allowed before consuming is halted.

Type: int

Default: 1024

`max_reconnects`

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

Requires version 4.56.0 or later.

Type: int

`queue`

An optional queue group to consume as. Used to configure a push consumer.

Type: string

`stream`

A stream to consume from. Either a subject or stream must be specified.

Type: string

`subject`

A subject to consume from. Supports wildcards for consuming multiple subjects. Either a subject or stream must be specified.

Type: string

# Examples:
subject: foo.bar.baz

# ---

subject: foo.*.baz

# ---

subject: foo.bar.*

# ---

subject: foo.>

`tls`

Configure Transport Layer Security (TLS) settings to secure network connections. This includes options for standard TLS as well as mutual TLS (mTLS) authentication where both client and server authenticate each other using certificates. Key configuration options include enabled to enable TLS, client_certs for mTLS authentication, root_cas/root_cas_file for custom certificate authorities, and skip_cert_verify for development environments.

Type: object

`tls.client_certs[]`

A list of client certificates for mutual TLS (mTLS) authentication. Configure this field to enable mTLS, authenticating the client to the server with these certificates.

You must set tls.enabled: true for the client certificates to take effect.

Certificate pairing rules: For each certificate item, provide either:

Inline PEM data using both cert and key or
File paths using both cert_file and key_file.

Mixing inline and file-based values within the same item is not supported.

Type: array<object>

Default: []

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


# ---

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

`tls.client_certs[].cert`

The plaintext certificate to use for TLS authentication. Must be paired with the corresponding private key in the key field when using inline PEM data for mTLS client certificates.

Type: string

Default: ""

`tls.client_certs[].cert_file`

The path to a file containing the certificate to use for TLS authentication. Must be paired with the corresponding private key file in the key_file field when using file-based configuration for mTLS client certificates.

Type: string

Default: ""

`tls.client_certs[].key`

Private key for mTLS client certificate as inline PEM data. Must correspond to the client certificate specified in the cert field. Use this field together with cert when providing certificate data inline rather than through files.

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`

Path to private key file for mTLS client certificate in PEM format. Must correspond to the client certificate specified in the cert_file field. Use this field together with cert_file when loading certificate data from files.

Type: string

Default: ""

`tls.client_certs[].password`

The password to use for the private key (specified in the key or key_file fields), if it is password-protected. The PKCS#1 and PKCS#8 formats are supported. Supports environment variable interpolation for secure password management.

The pbeWithMD5AndDES-CBC algorithm is obsolete and not supported for the PKCS#8 format. This algorithm does not authenticate the ciphertext, making it 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.

Requires version 4.3.0 or later.

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.

Type: bool

Default: false

`tls.enabled`

Whether to enable TLS for secure connections. Set to true to enable TLS encryption. Required to be true for other TLS options (like client_certs, root_cas, etc.) to take effect.

Type: bool

Default: false

`tls.root_cas`

Specify a root certificate authority to use (optional). This is a string that represents a certificate chain from the parent-trusted root certificate, through possible intermediate signing certificates, to the host certificate. Use either this field for inline certificate data or root_cas_file for file-based certificate loading.

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`

Specify the path to a root certificate authority file (optional). This is a file, often with a .pem extension, which contains a certificate chain from the parent-trusted root certificate, through possible intermediate signing certificates, to the host certificate. Use either this field for file-based certificate loading or root_cas for inline certificate data.

Type: string

Default: ""

# Examples:
root_cas_file: ./root_cas.pem

`tls.skip_cert_verify`

Whether to skip server-side certificate verification. Set to true only for testing environments as this reduces security by disabling certificate validation. When using self-signed certificates or in development, this may be necessary, but should never be used in production. Consider using root_cas or root_cas_file to specify trusted certificates instead of disabling verification entirely.

Type: bool

Default: false

`tls_handshake_first`

Whether to perform the initial TLS handshake before sending the NATS INFO protocol message. This is required when connecting to some NATS servers that expect TLS to be established immediately after connection, before any protocol negotiation.

Requires version 4.60.0 or later.

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<string>

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

# ---

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

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nats_jetstream

Consume mirrored streams

Metadata

Fields

ack_wait

auth

auth.nkey

auth.nkey_file

auth.password

auth.token

auth.user

auth.user_credentials_file

auth.user_jwt

auth.user_nkey_seed

bind

create_stream

deliver

durable

extract_tracing_map

max_ack_pending

max_reconnects

queue

stream

subject

tls

tls.client_certs[]

tls.client_certs[].cert

tls.client_certs[].cert_file

tls.client_certs[].key

tls.client_certs[].key_file

tls.client_certs[].password

tls.enable_renegotiation

tls.enabled

tls.root_cas

tls.root_cas_file

tls.skip_cert_verify

tls_handshake_first

urls[]

`ack_wait`

`auth`

`auth.nkey`

`auth.nkey_file`

`auth.password`

`auth.token`

`auth.user`

`auth.user_credentials_file`

`auth.user_jwt`

`auth.user_nkey_seed`

`bind`

`create_stream`

`deliver`

`durable`

`extract_tracing_map`

`max_ack_pending`

`max_reconnects`

`queue`

`stream`

`subject`

`tls`

`tls.client_certs[]`

`tls.client_certs[].cert`

`tls.client_certs[].cert_file`

`tls.client_certs[].key`

`tls.client_certs[].key_file`

`tls.client_certs[].password`

`tls.enable_renegotiation`

`tls.enabled`

`tls.root_cas`

`tls.root_cas_file`

`tls.skip_cert_verify`

`tls_handshake_first`

`urls[]`