Mem Cache

Mem Cache is implemented based on lru-cache

Create Mem Cache

For example, create a Mem Cache student in the module demo-student, to cache student data

1. Cli Command

$ vona :create:bean cacheMem student --module=demo-student

2. Menu Command

TIP

Context menu - [Module Path]: Vona Bean/Cache Mem

Mem Cache Definition

export type TCacheMemStudentKey = string;
export interface TCacheMemStudentData { id: string; name: string }

@CacheMem({
  max: 500,
  ttl: 2 * 3600 * 1000,
})
export class CacheMemStudent
  extends BeanCacheMemBase<TCacheMemStudentKey, TCacheMemStudentData> {}

• TCacheMemStudentKey: Defines the type of the cache key
• TCacheMemStudentData: Defines the type of the cache data

Mem Cache Parameters

Parameters can be configured for Mem Cache

@CacheMem({
  max: 500,
  ttl: 2 * 3600 * 1000,
  updateAgeOnGet: true,
  updateAgeOnHas: false,
  broadcastOnSet: false,
  disableInstance: false,
  disableTransactionCompensate: false,
})
class CacheMemStudent {}

Name	Type	Default	Description
max	number		Maximum number of items allowed in the cache
ttl	number		Cache expiration time
updateAgeOnGet	boolean	true	Whether to update the ttl when reading from the cache
updateAgeOnHas	boolean	false	Whether to update the ttl when checking if the cache exists
broadcastOnSet	boolean	'del'|false	Whether to broadcast changes to other Workers when setting the cache. Set to del to broadcast deletion to other Workers’ caches
disableInstance	boolean	false	Whether to disable instance isolation. By default, caches between multiple instances are isolated
disableTransactionCompensate	boolean	false	Whether to disable transaction compensation. Enabling transaction compensation ensures cache data consistency

App Config

Mem Cache parameters can be configured in App Config

src/backend/config/config/config.ts

// onions
config.onions = {
  cacheMem: {
    'demo-student:student': {
      max: 500,
      ttl: 2 * 3600 * 1000,
      updateAgeOnGet: true,
      updateAgeOnHas: false,
      broadcastOnSet: false,
      disableInstance: false,
      disableTransactionCompensate: false,
    },
  },
};

Mem Cache Enable/Disable

You can control enable/disable of Mem Cache

1. Enable

src/backend/config/config/config.ts

// onions
config.onions = {
  cacheMem: {
    'demo-student:student': {
+     enable: true,
    },
  },
};

2. Meta

Allows Mem Cache to take effect in a specified operating environment

Name	Type	Description
flavor	string|string[]	See: Runtime Environments and Flavors
mode	string|string[]	See: Runtime Environments and Flavors

• Example

@CacheMem({
+ meta: {
+   flavor: 'normal',
+   mode: 'dev',
+ },
})
class CacheMemStudent {}

Using Mem Cache

class ControllerStudent {
  @Web.get('test')
  async test() {
    const student = { id: '1', name: 'tom' };
    this.scope.cacheMem.student.set(student, '1');
    const value = this.scope.cacheMem.student.get('1');
    assert.deepEqual(student, value);
  }
}

• this.scope.cacheMem.student: Gets the Mem Cache instance through the module scope

Cache method parameters

Take the set method as an example to introduce the parameters of the cache method

this.scope.cacheMem.student.set(student, '1', {
  ttl: 2 * 3600 * 1000,
  broadcastOnSet: 'del',
  disableTransactionCompensate: true,
  db: this.ctx.db,
});

Name	Type	Description
ttl	number	Cache expiration time
broadcastOnSet	boolean | 'del'	Whether to broadcast changes to other Workers when setting the cache. Set to del to broadcast deletion to other Workers’ caches
disableTransactionCompensate	boolean	Whether to disable transaction compensation
db	ServiceDb	This db object is used when performing transaction compensation. By default, the db object in the context is automatically used

• db: VonaJS supports multiple databases/datasources, so transaction compensation can be precisely controlled through db

Cache methods

Name	Description
get	Read cache
mget	Read multiple caches at once
peek	Retrieve cache without updating its TTL
set	Set cache
mset	Set multiple caches at once
getset	Set new cache and return the old value
has	Check if cache exists
del	Delete cache
mdel	Delete multiple caches at once
clear	Clear all caches