Redis PubSub

Last updated: 5 minutes read.

Publishes messages through the Redis PubSub model. It is not possible to guarantee that messages have been received.

Common

# Common config fields, showing default values
output:
  label: ""
  redis_pubsub:
    url: redis://:6397 # No default (required)
    channel: "" # No default (required)
    max_in_flight: 64
    batching:
      count: 0
      byte_size: 0
      period: ""
      check: ""

Advanced

# All config fields, showing default values
output:
  label: ""
  redis_pubsub:
    url: redis://:6397 # No default (required)
    kind: simple
    master: ""
    tls:
      enabled: false
      skip_cert_verify: false
      enable_renegotiation: false
      root_cas: ""
      root_cas_file: ""
      client_certs: []
    channel: "" # No default (required)
    max_in_flight: 64
    batching:
      count: 0
      byte_size: 0
      period: ""
      check: ""
      processors: [] # No default (optional)

This output will interpolate functions within the channel field, you can find a list of functions here.

Performance

This output benefits from sending multiple messages in flight in parallel for improved performance. You can tune the max number of in flight messages (or message batches) with the field max_in_flight.

This output benefits from sending messages as a batch for improved performance. Batches can be formed at both the input and output level.

Fields

url

The URL of the target Redis server. Database is optional and is supplied as the URL path.

Type: string

# Examples

url: redis://:6397

url: redis://localhost:6379

url: redis://foousername:foopassword@redisplace:6379

url: redis://:foopassword@redisplace:6379

url: redis://localhost:6379/1

url: redis://localhost:6379/1,redis://localhost:6380/1

kind

Specifies a simple, cluster-aware, or failover-aware redis client.

Type: string
Default: "simple"
Options: simple, cluster, failover.

master

Name of the redis master when kind is failover

Type: string
Default: ""

# Examples

master: mymaster

tls

Custom TLS settings can be used to override system defaults.

Troubleshooting

Some cloud hosted instances of Redis (such as Azure Cache) might need some hand holding in order to establish stable connections. Unfortunately, it is often the case that TLS issues will manifest as generic error messages such as “i/o timeout”. If you’re using TLS and are seeing connectivity problems consider setting enable_renegotiation to true, and ensuring that the server supports at least TLS version 1.2.

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

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. Warning: Since it does not authenticate the ciphertext, it is vulnerable to padding oracle attacks that can let an attacker recover the plaintext.

Type: string
Default: ""

# Example

password: foo

channel

The channel to publish messages to. This field supports interpolation functions.

Type: string

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

batching

Allows you to configure a batching policy.

Type: object

# Examples

batching:
  byte_size: 5000
  count: 0
  period: 1s

batching:
  count: 10
  period: 1s

batching:
  check: this.contains("END BATCH")
  count: 0
  period: 1m

batching.count

A number of messages at which the batch should be flushed. If 0 disables count based batching.

Type: int
Default: 0

batching.byte_size

An amount of bytes at which the batch should be flushed. If 0 disables size based batching.

Type: int
Default: 0

batching.period

A period in which an incomplete batch should be flushed regardless of its size.

Type: string
Default: ""

# Examples

period: 1s

period: 1m

period: 500ms

batching.check

A Bloblang query that should return a boolean value indicating whether a message should end a batch.

Type: string
Default: ""

# Examples

check: this.type == "end_of_transaction"

batching.processors

A list of processors to apply to a batch as it is flushed. This allows you to aggregate and archive the batch however you see fit. Please note that all resulting messages are flushed as a single batch, therefore splitting the batch into smaller batches using these processors is a no-op.

Type: array

# Examples

processors:
  - archive:
      format: concatenate

processors:
  - archive:
      format: lines

processors:
  - archive:
      format: json_array