redis_script

Performs actions against Redis using LUA scripts.

Introduced in version 4.11.0.

Common
Advanced

# Common config fields, showing default values
label: ""
redis_script:
  url: redis://:6379 # No default (required)
  script: return redis.call('set', KEYS[1], ARGV[1]) # No default (required)
  args_mapping: root = [ this.key ] # No default (required)
  keys_mapping: root = [ this.key ] # No default (required)

# Advanced config fields, showing default values
label: ""
redis_script:
  url: redis://:6379 # No default (required)
  kind: simple
  master: ""
  tls:
    enabled: false
    skip_cert_verify: false
    enable_renegotiation: false
    root_cas: ""
    root_cas_file: ""
    client_certs: []
  script: return redis.call('set', KEYS[1], ARGV[1]) # No default (required)
  args_mapping: root = [ this.key ] # No default (required)
  keys_mapping: root = [ this.key ] # No default (required)
  retries: 3
  retry_period: 500ms

Actions are performed for each message and the message contents are replaced with the result.

In order to merge the result into the original message compose this processor within a branch processor.

Examples

Running a script

The following example will use a script execution to get next element from a sorted set and set its score with timestamp unix nano value.

pipeline:
  processors:
    - redis_script:
        url: TODO
        script: |
          local value = redis.call("ZRANGE", KEYS[1], '0', '0')

          if next(elements) == nil then
            return ''
          end

          redis.call("ZADD", "XX", KEYS[1], ARGV[1], value)

          return value
        keys_mapping: 'root = [ meta("key") ]'
        args_mapping: 'root = [ timestamp_unix_nano() ]'

Fields

`url`

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

Type: string

# Examples

url: redis://:6379

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 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}

`script`

A script to use for the target operator. It has precedence over the ‘command’ field.

Type: string

# Examples

script: return redis.call('set', KEYS[1], ARGV[1])

`args_mapping`

A Bloblang mapping which should evaluate to an array of values matching in size to the number of arguments required for the specified Redis script.

Type: string

# Examples

args_mapping: root = [ this.key ]

args_mapping: root = [ meta("kafka_key"), "hardcoded_value" ]

`keys_mapping`

A Bloblang mapping which should evaluate to an array of keys matching in size to the number of arguments required for the specified Redis script.

Type: string

# Examples

keys_mapping: root = [ this.key ]

keys_mapping: root = [ meta("kafka_key"), this.count ]

`retries`

The maximum number of retries before abandoning a request.

Type: int

Default: 3

`retry_period`

The time to wait before consecutive retry attempts.

Type: string

Default: "500ms"