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redis_backend

Redis backend implementation for the Merlin application.

This module provides a concrete implementation of the ResultsBackend interface using Redis as the underlying database. It defines the RedisBackend class, which manages interactions with Redis-specific store classes for different data models, including CRUD operations and database flushing.

RedisBackend

Bases: ResultsBackend

A Redis-based implementation of the ResultsBackend interface for interacting with a Redis database.

Attributes:

Name Type Description
backend_name str

The name of the backend (e.g., "redis").
client Redis

The Redis client used for database operations.

Methods:

Name Description
get_version

Query Redis for the current version.
get_connection_string

Retrieve the connection string used to connect to Redis.
flush_database

Remove every entry in the Redis database.
save

Save a BaseDataModel entity to the Redis database.
retrieve

Retrieve an entity from the appropriate store based on the given query identifier and store type.
retrieve_all

Retrieve all entities from the specified store.
delete

Delete an entity from the specified store.
Source code in merlin/backends/redis/redis_backend.py 
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class RedisBackend(ResultsBackend):
    """
    A Redis-based implementation of the `ResultsBackend` interface for interacting with a Redis database.

    Attributes:
        backend_name (str): The name of the backend (e.g., "redis").
        client (Redis): The Redis client used for database operations.

    Methods:
        get_version:
            Query Redis for the current version.

        get_connection_string:
            Retrieve the connection string used to connect to Redis.

        flush_database:
            Remove every entry in the Redis database.

        save:
            Save a `BaseDataModel` entity to the Redis database.

        retrieve:
            Retrieve an entity from the appropriate store based on the given query identifier and store type.

        retrieve_all:
            Retrieve all entities from the specified store.

        delete:
            Delete an entity from the specified store.
    """

    def __init__(self):
        """
        Initialize the `RedisBackend` instance, setting up the Redis client connection and store mappings.
        """
        from merlin.config.configfile import CONFIG  # pylint: disable=import-outside-toplevel
        from merlin.config.results_backend import get_connection_string  # pylint: disable=import-outside-toplevel

        # Get the Redis client connection
        redis_config = {"url": get_connection_string(), "decode_responses": True}
        if CONFIG.results_backend.name == "rediss":
            redis_config.update({"ssl_cert_reqs": getattr(CONFIG.results_backend, "cert_reqs", "required")})
        self.client: Redis = Redis.from_url(**redis_config)

        # Create instances of each store in our database
        stores = {
            "study": RedisStudyStore(self.client),
            "run": RedisRunStore(self.client),
            "logical_worker": RedisLogicalWorkerStore(self.client),
            "physical_worker": RedisPhysicalWorkerStore(self.client),
        }

        super().__init__("redis", stores)

    def get_version(self) -> str:
        """
        Query the Redis backend for the current version.

        Returns:
            A string representing the current version of Redis.
        """
        client_info = self.client.info()
        return client_info.get("redis_version", "N/A")

    def flush_database(self):
        """
        Remove everything stored in Redis.
        """
        self.client.flushdb()

__init__()

Initialize the RedisBackend instance, setting up the Redis client connection and store mappings.

Source code in merlin/backends/redis/redis_backend.py 
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def __init__(self):
    """
    Initialize the `RedisBackend` instance, setting up the Redis client connection and store mappings.
    """
    from merlin.config.configfile import CONFIG  # pylint: disable=import-outside-toplevel
    from merlin.config.results_backend import get_connection_string  # pylint: disable=import-outside-toplevel

    # Get the Redis client connection
    redis_config = {"url": get_connection_string(), "decode_responses": True}
    if CONFIG.results_backend.name == "rediss":
        redis_config.update({"ssl_cert_reqs": getattr(CONFIG.results_backend, "cert_reqs", "required")})
    self.client: Redis = Redis.from_url(**redis_config)

    # Create instances of each store in our database
    stores = {
        "study": RedisStudyStore(self.client),
        "run": RedisRunStore(self.client),
        "logical_worker": RedisLogicalWorkerStore(self.client),
        "physical_worker": RedisPhysicalWorkerStore(self.client),
    }

    super().__init__("redis", stores)

flush_database()

Remove everything stored in Redis.

Source code in merlin/backends/redis/redis_backend.py 
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def flush_database(self):
    """
    Remove everything stored in Redis.
    """
    self.client.flushdb()

get_version()

Query the Redis backend for the current version.

Returns:

Type Description
str

A string representing the current version of Redis.
Source code in merlin/backends/redis/redis_backend.py 
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def get_version(self) -> str:
    """
    Query the Redis backend for the current version.

    Returns:
        A string representing the current version of Redis.
    """
    client_info = self.client.info()
    return client_info.get("redis_version", "N/A")