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eval.go

eval.go - Overview​

This file contains the evaluation logic for various DiceDB commands, including authentication (AUTH), server information (HELLO), and utility functions (SLEEP). It also defines the EvalResponse struct for encapsulating command results and errors.

Detailed Documentation​

Variables​

  • TxnCommands map[string]bool: A map indicating which commands are transaction-related (e.g., EXEC, DISCARD).
  • serverID string: Stores the server's ID in the format "host:port".
  • diceCommandsCount int: Stores the number of DiceDB commands.

Constants​

  • Uninitialized exDurationState: Represents an uninitialized expiration duration state.
  • Initialized exDurationState: Represents an initialized expiration duration state.
  • IncrBy jsonOperation: String constant for "INCRBY" operation.
  • MultBy jsonOperation: String constant for "MULTBY" operation.
  • defaultRootPath string: String constant for default JSON root path "$".
  • maxExDuration int64: Max expiration duration.
  • CountConst string: String constant for "COUNT".

Struct EvalResponse​

  • Purpose: Represents the response from evaluating a command.
  • Fields:
    • Result interface{}: The result of the command evaluation.
    • Error error: Any error that occurred during evaluation.
  • Methods:
    • makeEvalResult(result interface{}) *EvalResponse: Creates a new EvalResponse with the given result and a nil error.
      • Parameters:
        • result interface{}: The result of the store operation.
      • Returns: A new EvalResponse with the given result and nil error.
    • makeEvalError(err error) *EvalResponse: Creates a new EvalResponse with the given error and a nil result.
      • Parameters:
        • err error: The error that occurred during the store operation.
      • Returns: A new EvalResponse with the given error and nil result.

Functions​

  • EvalAUTH(args []string, c *comm.Client) []byte: Evaluates the AUTH command.
    • Purpose: Authenticates a user against the configured username and password.
    • Parameters:
      • args []string: The arguments provided to the AUTH command (password, or username and password).
      • c *comm.Client: The client connection.
    • Returns: An encoded "OK" response on success, or an encoded error message on failure.
  • evalHELLO(args []string, store *dstore.Store) []byte: Evaluates the HELLO command.
    • Purpose: Returns server information.
    • Parameters:
      • args []string: The arguments provided to the HELLO command.
      • store *dstore.Store: The data store.
    • Returns: An encoded response containing server details like protocol version, server ID, mode, role, and modules.
  • evalSLEEP(args []string, store *dstore.Store) []byte: Evaluates the SLEEP command.
    • Purpose: Makes the server sleep for a specified duration.
    • Parameters:
      • args []string: The arguments provided to the SLEEP command (sleep duration in seconds).
      • store *dstore.Store: The data store.
    • Returns: RespOK after sleeping, or an error if the duration is invalid.

Getting Started Relevance​