ElasticsearchBackend

Elasticsearch Backend.

Attributes

Attribute	Type	Description
index	string = celery	The name of the Elasticsearch index where task results are stored.
doc_type	string = null	The document type used for indexing and retrieving results within the Elasticsearch index.
scheme	string = http	The protocol used to connect to the Elasticsearch server, such as http or https.
host	string = localhost	The hostname or IP address of the Elasticsearch server.
port	integer = 9200	The network port on which the Elasticsearch server is listening.
username	string = null	The username for authenticating with the Elasticsearch server via HTTP Basic Auth.
password	string = null	The password for authenticating with the Elasticsearch server via HTTP Basic Auth.
es_retry_on_timeout	boolean = false	Flag indicating whether the client should retry requests that fail due to a timeout.
es_timeout	integer = 10	The maximum number of seconds to wait for a response from the Elasticsearch server before timing out.
es_max_retries	integer = 3	The maximum number of times the client will attempt to retry a failed request.

---

Constructor

Signature

def ElasticsearchBackend(
    url: string = null,
    *args: any = null,
    **kwargs: any = null
) - > null

Parameters

Name	Type	Description
url	string = null	The URL used to connect to the Elasticsearch server, containing scheme, host, port, and credentials.
*args	any = null	Variable length argument list passed to the parent class constructor.
**kwargs	any = null	Arbitrary keyword arguments passed to the parent class constructor.

---

Methods

---

exception_safe_to_retry()

@classmethod
def exception_safe_to_retry(
    exc: Exception
) - > boolean

Determines if a given exception is safe to retry based on Elasticsearch error codes and transport errors.

Parameters

Name	Type	Description
exc	Exception	The exception instance caught during an Elasticsearch operation.

Returns

Type	Description
boolean	True if the exception is a transient or retryable error like a timeout or specific HTTP status codes (401, 409, 500, 502, 504), otherwise False.

---

get()

@classmethod
def get(
    key: string
) - > any

Fetches the result associated with a specific key from the Elasticsearch index.

Parameters

Name	Type	Description
key	string	The unique identifier for the task result document.

Returns

Type	Description
any	The task result stored in the document's source, or None if the key is not found.

---

set()

@classmethod
def set(
    key: string,
    value: any
) - > null

Stores a value in the backend for the given key without specifying a specific task state.

Parameters

Name	Type	Description
key	string	The unique identifier for the data being stored.
value	any	The data to be persisted in the Elasticsearch index.

Returns

Type	Description
null	null

---

encode()

@classmethod
def encode(
    data: any
) - > any

Serializes task metadata, optionally encoding specific fields like 'result' and 'traceback' if full text saving is disabled.

Parameters

Name	Type	Description
data	any	The task metadata or result object to be encoded for storage.

Returns

Type	Description
any	The encoded data, either as a serialized string or a dictionary with encoded sub-fields.

---

decode()

@classmethod
def decode(
    payload: any
) - > any

Deserializes task metadata retrieved from the backend into Python objects.

Parameters

Name	Type	Description
payload	any	The raw data or dictionary retrieved from Elasticsearch.

Returns

Type	Description
any	The decoded task metadata, including deserialized results and tracebacks.

---

mget()

@classmethod
def mget(
    keys: array
) - > array

Retrieves multiple task results simultaneously for a list of keys.

Parameters

Name	Type	Description
keys	array	A list of document IDs to fetch from the index.

Returns

Type	Description
array	A list of task results corresponding to the provided keys.

---

delete()

@classmethod
def delete(
    key: string
) - > null

Removes a specific task result document from the Elasticsearch index.

Parameters

Name	Type	Description
key	string	The document ID to be deleted.

Returns

Type	Description
null	null

---

server()

@classmethod
def server() - > elasticsearch.Elasticsearch

Provides a cached Elasticsearch client instance, initializing the connection on the first access.

Returns

Type	Description
elasticsearch.Elasticsearch	The active Elasticsearch client used for all backend operations.

---