Description

The Redis Function interacts with Redis stores, setting and getting key-hash and key-value combinations. Redis' in-memory caching of these key pairs enables large lookup tables that would be cumbersome with a .CSV or binary lookup file.

You can use LogStream Collectors (e.g., a REST Collector) to retrieve reference data from desired endpoints, and then use this Function to store the data on Redis and retrieve it to enrich your production data. Note that LogStream does not cache the data returned from this Redis Function.

Usage

Filter: Filter expression (JS) that selects data to be fed through the Function. Defaults to true, meaning that all events will be evaluated.

Description: Simple description of this Function. Defaults to empty.

Final: If true, stops data from being fed to downstream Functions. Defaults to No.

Result field: Name of the field in which to store the returned value. (Leave empty to discard the returned value.)

Command: Redis command to perform. Required. (A complete list of Redis commands is at: https://redis.io/commands.)

Key: A JavaScript expression to compute the value of the key to operate on. Can also be a constant, e.g.: username. This is a required field. Click the icon at right to open a validation modal.

Args: A JavaScript expression to compute arguments to the operation. Can return an array. Click the icon at right to open a validation modal.

Redis URL: Redis URL to connect to. The format is:
[redis[s]:]//[[user][:[email protected]]][host][:port][/db-number][?db=db-number[&password=bar[&option=value]]]

For example: redis://user:[email protected]:6379/0?foo=bar&qux=baz

With no user specified: redis://[email protected]:6379/0?foo=bar&qux=baz

🚧

Redis URL Vs. Redis ACL

Through LogStream 2.4.3, the Redis URL field has limited compatibility with Redis 6.x's ACL (Access Control List) feature. When using an ACL, point this field to the Redis default account, either with a password (e.g., redis://default:[email protected]:6379) or with no password (redis://192.168.1.20:6379).

Do not specify a specific user other than default, or authentication against Redis will fail.

Advanced Settings

Max blocking time: Maximum amount of time (in seconds) before assuming that Redis is down and passing events through. Defaults to 60 seconds. Use 0 to disable timeouts.

Examples

Scenario A: Set and Get

This Pipeline demonstrates the use of a pair of Redis Functions. The first Function sets two key-value pairs in Redis. The second Function gets their values, by key, into two corresponding new Result fields.

Redis Function #1

Description: Set keys to Redis

Command: set
Key: 'myFieldA'
Args: 420

Command: set
Key: 'myFieldB'
Args: 'sample value'

Redis Function #2

Description: Read keys from Redis

Result field: myField_AA
Command: get
Key: 'myFieldA'

Result field: myField_BB
Command: get
Key: 'myFieldB'

Scenario B: Multiple‑Argument Arrays

This example demonstrates how to configure a Redis Function that supplies an array of multiple arguments to Redis commands (in this example, lset and lrange).

Redis Function

Description: Push arrays of multiple arguments to Redis

Result field: rs1
Command: rpush
Key: "mylist"
Args: 'one'

Result field: rs2
Command: rpush
Key: "mylist"
Args: 'two'

Result field: rs3
Command: rpush
Key: "mylist"
Args: 'three

Result field: rs4
Command: lset
Key: "mylist"
Args: [0,'four']

Result field: rs5
Command: lset
Key: "mylist"
Args: [-2,'five']

Result field: rs6
Command: lrange
Key: "mylist"
Args: [0,-1]

Try This at Home

The Pipeline below contains only this example Function. You can import it into your own LogStream environment, fill in the url with your own credentials, and further modify it to meet your needs.

{
  "id": "redis-multiple-args",
  "conf": {
    "output": "default",
    "groups": {},
    "asyncFuncTimeout": 1000,
    "functions": [
      {
        "filter": "true",
        "conf": {
          "commands": [
            {
              "outField": "rs1",
              "command": "rpush",
              "keyExpr": "\"mylist\"",
              "argsExpr": "'one'"
            },
            {
              "outField": "rs2",
              "command": "rpush",
              "keyExpr": "\"mylist\"",
              "argsExpr": "'two'"
            },
            {
              "outField": "rs3",
              "command": "rpush",
              "keyExpr": "\"mylist\"",
              "argsExpr": "'three'"
            },
            {
              "command": "lset",
              "keyExpr": "\"mylist\"",
              "argsExpr": "[0,'four']",
              "outField": "rs4"
            },
            {
              "outField": "rs5",
              "command": "lset",
              "keyExpr": "\"mylist\"",
              "argsExpr": "[-2,'five']"
            },
            {
              "outField": "rs6",
              "command": "lrange",
              "keyExpr": "\"mylist\"",
              "argsExpr": "[0,-1]"
            }
          ],
          "maxBlockSecs": 60,
          "url": "redis://<your-credentials-here>"
        },
        "id": "redis",
        "disabled": false,
        "description": "Push arrays of multiple arguments to Redis"
      }
    ]
  }
}