Embulk input/output plugin for Redis

This is a fork of https://github.com/frsyuki/embulk-plugin-redis

The biggest change is that it accepts a Redis URL connection string. This makes it easy to output to a Compose.io hosted Redis for example.

It also fixes a few issues and adds some support for working with JSON. It will now, optionally, save a JSON string into Redis with the output plugin. Otherwise, it stores a hash.

This plugin runs without transaction for now.

• host host name of the Redis server (string, default: "localhost")
• port port of the Redis server (integer, default: 6379)
• db destination database number (integer, default: 0)
• key_prefix key prefix to search keys for input plugin (string)
• key key name for output plugin (string, required)

out:
  type: redis
  host: localhost
  port: 6379
  db: 0
  key: user_name

in:
  type: redis
  host: localhost
  port: 6379
  db: 0
  key_prefix: user_

Assuming Embulk is ingesting log files with line by line JSON strings...This will import to Redis using a key found within the JSON object. An example line item may be:

{"id": "myId", "name": "Bob"}

The following configuration would use the id value "myId" as a key in Redis with a string value of the entire record.

out:
  type: redis
  url: redis://x:21345@host.com:6379
  db: 0
  is_json: true
  key: id