nats_jetstream_batched

Reads messages from NATS JetStream subjects.

Common

# Common config fields, showing default values
input:
  label: ""
  nats_jetstream_batched:
    urls: [] # No default (required)
    name: "" # No default (required)
    stream: "" # No default (required)
    filter_subjects: [] # No default (optional)
    deliver: all
    start_sequence: 0 # No default (optional)
    start_time: "" # No default (optional)
    batch_size: 1
    flush_wait: 100ms

Advanced

# Advanced config fields, showing default values
input:
  label: ""
  nats_jetstream_batched:
    urls: [] # No default (required)
    name: "" # No default (required)
    stream: "" # No default (required)
    filter_subjects: [] # No default (optional)
    deliver: all
    start_sequence: 0 # No default (optional)
    start_time: "" # No default (optional)
    ack_wait: 30s
    max_ack_pending: 1024
    batch_size: 1
    flush_wait: 100ms
    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)

Consume mirrored streams

In the case where a stream being consumed is mirrored from a different JetStream domain the stream cannot be resolved from the subject name alone, and so the stream name as well as the subject (if applicable) must both be specified.

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

Connection name

When monitoring and managing a production NATS system, it is often useful to know which connection a message was send/received from. This can be achieved by setting the connection name option when creating a NATS connection.

Wombat will automatically set the connection name based off the label of the given NATS component, so that monitoring tools between NATS and Wombat can stay in sync.

Authentication

There are several components within Wombat which uses NATS services. You will find that each of these components support optional advanced authentication parameters for [https://docs.nats.io/using-nats/developer/connecting/creds](https://docs.nats.io/nats-server/configuration/securing_nats/auth_intro/nkey_auth and )(User Credentials).

See an [[https://docs.nats.io/running-a-nats-service/configuration/securing_nats/auth_intro/nkey_auth](https://docs.nats.io/running-a-nats-service/nats_admin/security/jwt](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 [[https://docs.nats.io/running-a-nats-service/configuration/securing_nats/auth_intro/nkey_auth](https://docs.nats.io/nats-server/configuration/securing_nats/jwt#json-web-tokens](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 [[https://docs.nats.io/using-nats/developer/connecting/creds](https://docs.nats.io/nats-tools/nsc](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

name

The name of the consumer

Type: string

stream

The stream to consume from

Type: string

filter_subjects

The list of subjects to filter on

Type: array

# Examples

filter_subjects: foo.bar.baz

filter_subjects: foo.*.baz

filter_subjects: foo.bar.*

filter_subjects: foo.>

deliver

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

Type: string

Default: "all"

Option	Summary
all	Deliver all available messages.
by_start_sequence	Deliver starting with messages published after a specific sequence number.
by_start_time	Deliver starting with messages published after a specific time.
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.

start_sequence

The start sequence when using the by_start_seqyuence deliver policy

Type: int

start_time

The start time when using the by_start_time deliver policy. Should be in RFC3339 format

Type: string

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

max_ack_pending

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

Type: int

Default: 1024

batch_size

The maximum number of messages to consume in a single batch

Type: int

Default: 1

flush_wait

the amount of time to wait for a new message before closing an incomplete batch

Type: string

Default: "100ms"

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.

Sensitive Information

This field contains sensitive information that usually shouldn’t be added to a config directly, read our secrets page for more info.

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.

Sensitive Information

This field contains sensitive information that usually shouldn’t be added to a config directly, read our secrets page for more info.

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.

Sensitive Information

This field contains sensitive information that usually shouldn’t be added to a config directly, read our secrets page for more info.

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).

Sensitive Information

This field contains sensitive information that usually shouldn’t be added to a config directly, read our secrets page for more info.

Type: string

auth.user_nkey_seed

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

Sensitive Information

This field contains sensitive information that usually shouldn’t be added to a config directly, read our secrets page for more info.

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 3.45.0 or newer

# Examples

extract_tracing_map: root = @

extract_tracing_map: root = this.meta.span