Memcached

Learn more about the component and how to use it.

The Memcached component allows you to perform operations on Memcached servers.

Memcached is an open source distributed memory caching system that uses an in-memory key-value model for data storage. For more information, see the official website.

Parameters

Take a look at the configuration parameters of the component. Parameters supported by Double Braces expressions are marked with (DB).

Parameter	Description	Default value	Data yype
Account	Account to be used to authenticate on servers. Supported accounts: Basic.	N/A	String
Operation	Operation to be performed. The operations are: Get One, Get Many, Add, Set, Delete, Replace, Append, Prepend, Touch, Get And Touch, and CAS (Check And Set).	Get One	String
Addresses (DB)	Host and port (HOST:PORT) of the servers to connect to. Multiple addresses can be configured as HOST1:PORT1, HOSTn:PORTn.	N/A	String
Key (DB)	Key to be stored or retrieved.	N/A	String
Key Set (DB)	Key set to be retrieved. This option is only available when using operation Get Many and it expects an array of Strings containing the keys.	N/A	Array of Strings
Expiration	Time (in seconds) that the data must be kept in the database before expiring. If set with 0, the data will not expire.	N/A	Integer
Value (DB)	Value to be stored.	N/A	String
Connect Timeout	Maximum time (in milliseconds) to connect to Memcached servers.	30000	Integer
Operation Timeout	Maximum time (in milliseconds) to perform the Memcached operation.	30000	Integer
Advanced Settings	If the option is active, you can access the following configurations:	False	Boolean
- Raw Mode	When enabled, will consider Value as raw data (not JSON) and will store it as is. Retrieved content will also be displayed as a string with a raw result.	False	Boolean
- Is Binary Result	If enabled, will treat the result as binary content and will show output as a Base64 string.	False	Boolean
- Pool Size By Actual Consumers	If enabled, the number of pooled connections will be equivalent to the number of consumers configured during pipeline deployment. If disabled, then the pool size is given by the pipeline deployment size, irrespective of the number of consumers.	False	Boolean
Fail On Error	If the option is active, the execution of the pipeline with an error will be interrupted. Otherwise, the pipeline execution proceeds, but the result will show a false value for the “success” property.	False	Boolean

When using multiple servers, the same Basic credential must be used through all servers.

Usage examples

Retrieval operations

Get One

Retrieves only 1 record from the server by its Key.

• Account: <basic-account>

• Addresses: localhost:11211

• Operation: Get One

• Key: id_A

Output:

{
    "total": 1,
    "data": [
        {
        	"key": "id_A",
        	"value": <value>
        }
    ]
}

Get Many

Retrieve any number of records from the server by a Key Set.

• Account: <basic-account>

• Address: localhost:11211

• Operation: Get Many

• Key Set:

[
	"id_A",
	"id_B",
	"id_C",
	"id_D"
]

Output:

{
    "total": 4,
    "data": [
        {
        	"key": "id_A",
        	"value": <value>
        },
        {
        	"key": "id_B",
        	"value": <value>
        },
        {
        	"key": "id_C",
        	"value": <value>
        },
        {
        	"key": "id_D",
        	"value": <value>
        }
    ]
}

When retrieving data from a Memcached server, the component can only handle Java serializable objects and will always try to output them in JSON format or its string representation. If the retrieved value cannot be parsed into these formats, an Exception can be thrown.

Storage operations

Add

Stores a record on the server by its Key, Expiration and Value, only if it does not already exist.

• Account: <basic-account>

• Addresses: localhost:11211

• Operation: Add

• Key: id_A

• Expiration: 3600

• Value:

{
    "code": "A",
    "name": "John",
    "address": {
    	"street": "John's Street"
    },
    "number": [
    	"[phone]"
    ]
}

Output:

{
    "success": true,   //false, if the key already exists
    "command": "add"
}

Set

Stores a record on the server by its Key, Expiration and Value, overriding it if it already exists.

• Account: <basic-account>

• Addresses: localhost:11211

• Operation: Set

• Key: id_A

• Expiration: 3600

• Value:

{
    "code": "A",
    "name": "John",
    "address": {
    	"street": "John's Street"
    },
    "number": [
    	"[phone]"
    ]
}

Output:

{
    "success": true,
    "command": "set"
}

Replace

Replaces a record's Value by its Key, Expiration and the new Value, only if the record already exists.

• Account: <basic-account>

• Addresses: localhost:11211

• Operation: Replace

• Key: id_A

• Expiration: 3600

• Value:

{
    "code": "A",
    "name": "John",
    "address": {
    	"street": "John's Street"
    },
    "number": [
    	"[phone]"
    ]
}

Output:

{
    "success": true,   //false, if the key does not exist
    "command": "replace"
}

Append

Appends a value to a record's Value by its Key and the Value to be appended, only if the record already exists. Requires Raw Mode parameter to be enabled.

• Account: <basic-account>

• Addresses: localhost:11211

• Operation: Append

• Key: id_A

• Expiration: 3600

• Raw Mode: enabled

• Value:

" - value to be appended"

Output:

{
    "success": true,   //false, if the key does not exist
    "command": "append"
}

Important: since the Append operation appends new data to existing data without retrieving it, it is not possible to simply append complex data structures such as JSON objects. Therefore, the existing data must also have been stored as raw data, and the Raw Mode parameter must be enabled for this operation.

Prepend

Prepends a value to a record's Value by its Key and the Value to be prepended, only if the record alright exists. Requires Raw Mode parameter to be enabled.

• Account: <basic-account>

• Addresses: localhost:11211

• Operation: Prepend

• Key: id_A

• Expiration: 3600

• Raw Mode: enabled

• Value:

"value to be prepended - "

Output:

{
    "success": true,   //false, if the key does not exist
    "command": "prepend"
}

Since the Prepend operation prepends new data to existing data without retrieving it, it is not possible to simply prepend complex data structures such as JSON objects. Therefore, the existing data must also have been stored as raw data, and the Raw Mode parameter must be enabled for this operation.

CAS (Check And Set)

Update a record's Value by its Key, Expiration and the new Value, only if the record alright exists and if it wasn't changed during the record's retrieval. This operation is useful in environments with race conditions on updating cache data.

• Account: <basic-account>

• Addresses: localhost:11211

• Operation: CAS (Check And Set)

• Key: id_A

• Expiration: 3600

• Value:

{
    "code": "A",
    "name": "John",
    "address": {
    	"street": "John's Street"
    },
    "number": [
    	"[phone]"
    ]
}

Output:

{
    "success": true,   //false, if the key does not exist
    "command": "cas"
}

Delete operations

Delete

Delete a record from the server by its Key.

• Account: <basic-account>

• Addresses: localhost:11211

• Operation: Delete

• Key: id_A

Output:

{
    "success": true,    //false, if the key does not exist
    "command": "delete"
}

Touch operations

Touch

Updates a record's expiration by its Key and a new Expiration value.

• Account: <basic-account>

• Addresses: localhost:11211

• Operation: Touch

• Key: id_A

• Expiration: 3600

Output:

{
    "success": true,    //false, if the key does not exist
    "command": "touch"
}

Get And Touch

Retrieves only 1 record from the server by its Key while updating its Expiration value.

• Account: <basic-account>

• Addresses: localhost:11211

• Operation: Get And Touch

• Key: id_A

• Expiration: 3600

Output:

{
    "total": 1,
    "data": [
        {
        	"key": "id_A",
        	"value": <value>
        }
    ]
}

When retrieving data from a Memcached server, the component can only handle Java serializable objects and will always try to output them in JSON format or its string representation. If the retrieved value cannot be parsed into these formats, an Exception can be thrown.