Redis Quota

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The redisquota adapter can be used to support Istio’s quota management system. It depends on a Redis server to store quota values.

This adapter supports the quota template.

Params

redisquota adapter supports the rate limit quota using either fixed or rolling window algorithm. And it is using Redis as a shared data storage.

Example configuration:

redisServerUrl: localhost:6379
connectionPoolSize: 10
quotas:
- name: requestcount.quota.istio-system
  maxAmount: 50
  validDuration: 60s
  bucketDuration: 1s
  rateLimitAlgorithm: ROLLING_WINDOW
  overrides:
  - dimensions:
      destination: ratings
      source: reviews
    maxAmount: 12
  - dimensions:
      destination: reviews
    maxAmount: 5

Field	Type	Description	Required
`quotas`	`Quota[]`	The set of known quotas. At least one quota configuration is required	No
`redisServerUrl`	`string`	Redis connection string `<hostname>:<port number>` ex) localhost:6379	No
`connectionPoolSize`	`int64`	Maximum number of idle connections to redis Default is 10 connections per every CPU as reported by runtime.NumCPU.	No

Params.Override

Field	Type	Description	Required
`dimensions`	`map<string, string>`	The specific dimensions for which this override applies. String representation of instance dimensions is used to check against configured dimensions. `dimensions` should not be empty	No
`maxAmount`	`int64`	The upper limit for this quota override. This value should be bigger than 0	No

Params.Quota

Field	Type	Description	Required
`name`	`string`	The name of the quota	No
`maxAmount`	`int64`	The upper limit for this quota. max_amount should be bigger than 0	No
`validDuration`	`Duration`	The amount of time allocated quota remains valid before it is automatically released. This is only meaningful for rate limit quotas. value should be `0 < validDuration`	No
`bucketDuration`	`Duration`	The `bucketDuration` will be ignored if `rateLimitAlgorithm` is `FIXED_WINDOW` value should be `0 < bucketDuration < validDuration`	No
`rateLimitAlgorithm`	`QuotaAlgorithm`	Quota management algorithm. The default value is `FIXED_WINDOW`	No
`overrides`	`Override[]`	Overrides associated with this quota. The first matching override is applied.	No

Params.QuotaAlgorithm

Algorithms for rate-limiting:

Name	Description
`FIXED_WINDOW`	`FIXED_WINDOW` The fixed window approach can allow 2x peak specified rate, whereas the rolling-window doesn’t.
`ROLLING_WINDOW`	`ROLLING_WINDOW` The rolling window algorithm’s additional precision comes at the cost of increased redis resource usage.

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