RedisLock

Distributed lock that is implemented based on the Redis in-memory database.

Implements: Lock

Description

The RedisLock class allows you to create a distributed lock that is implemented based on the Redis in-memory database.

Configuration parameters

  • connection(s):
    • discovery_key: (optional) key to retrieve the connection from IDiscovery
    • host: host name or IP address
    • port: port number
    • uri: resource URI or connection string with all parameters in it
  • credential(s):
    • store_key: key to retrieve parameters from credential store
    • username: username (currently is not used)
    • password: user’s password
  • options:
    • retry_timeout: timeout in milliseconds to retry lock acquisition. (Default: 100)
    • retries: number of retries (default: 3)
    • db_num: database number in Redis (default 0)

References

  • *:discovery:*:*:1.0 - (optional) IDiscovery services
  • *:credential-store:*:*:1.0 - (optional) ICredentialStore to resolve credentials

Constructors

NewRedisLock

Creates a new instance of this lock.

NewRedisLock() *RedisLock

Methods

Close

Closes the component and frees used resources.

(c *RedisLock) Close(ctx context.Context, correlationId string) error

  • ctx: context.Context - operation context.
  • correlationId: string - (optional) transaction id used to trace execution through the call chain.

Configure

Configures a component by passing its configuration parameters.

(c *RedisLock) Configure(ctx context.Context, config *ConfigParams)

  • ctx; context.Context - operation context.
  • config: *ConfigParams - configuration parameters to be set.

IsOpen

Checks if the component is open.

(c *RedisLock) IsOpen() bool

  • returns: bool - true if the component is open and false otherwise.

Open

Opens the component.

(c *RedisLock) Open(ctx context.Context, correlationId string) error

  • ctx: context.Context - operation context.
  • correlationId: string - (optional) transaction id used to trace execution through the call chain.
  • returns: error - error or nil if no errors occurred.

ReleaseLock

Releases a prevously acquired lock by its key.

(c *RedisLock) ReleaseLock(ctx context.Context, correlationId string, key string) error

  • ctx: context.Context - operation context.
  • correlationId: string - (optional) transaction id used to trace execution through the call chain.
  • key: string - unique lock key to release.
  • returns: error - error or nil if no errors occurred.

SetReferences

Sets references to dependent components.

(c *RedisLock) SetReferences(ctx context.Context, references IReferences)

  • ctx: context.Context - operation context.
  • references: IReferences - references to locate the component dependencies.

TryAcquireLock

Makes a single attempt to acquire a lock by its key. It returns immediately a positive or negative result.

(c *RedisLock) TryAcquireLock(ctx context.Context, correlationId string, key string, ttl int64) (result bool, err error)

  • ctx: context.Context - operation context.
  • correlationId: string - (optional) transaction id used to trace execution through the call chain.
  • key: string - unique lock key to acquire.
  • ttl: int64 - lock timeout (time to live) in milliseconds.
  • returns: (result bool, err error) - true if lock was successfully acquired and false otherwise.

Examples

ctx := context.Background()

lock = NewRedisRedis();
lock.Configure(ctx, cconf.NewConfigParamsFromTuples(
  "host", "localhost",
  "port", 6379,
))

err = lock.Open(ctx, "123")
...

result, err := lock.TryAcquireLock(ctx, "123", "key1", 3000)
if result {
	// Processing...
}
err = lock.ReleaseLock(ctx, "123", "key1")
// Continue...