Crate redis_utils

redis_utils

Cohesive helpers built on top of redis-rs for:

• async transactions
• geting and seting json values

Async Transactions

A macro that helps you set up a safe async redis transaction.

Takes:

• A connection
• The name of a pipeline which it configures in atomic-mode.
• A set of keys to WATCH
• The body of the transaction that can get those keys, use the pipeline (for side effects) and if those keys change (and the EXEC component of the atomic pipeline fails), then the body will be re-executed.
• Allows for safe early returns (aborted transactions) with typed values, all keys will be un-watched during an early return.

tx!(&mut con, pipe, &["key1"], {
  let mut value: u8 = con.get("key1").await?;
  value = value + 1;

  Ok(pipe.set("key1", value))
});

Aborting a tx

tx!(&mut con, pipe, &["key1"], {
  let mut value: u8 = con.get("key1").await?;
  value = value + 1;

  if value == 69 {
    return Err(Abort(BadNumberFound));
  }

  Ok(pipe.set("key1", value))
});

Handling return values

let tx: Result<u8, TxError<NumberError> > = tx!(&mut con, pipe, &["key1"], {
  let mut value: u8 = con.get("key1").await?;
  value = value + 1;

  if value == 69 {
    return Err(Abort(BadNumberFound));
  }

  Ok(pipe.set("key1", value))
});

• The Ok(T) of tx is the type that’s handed to pipe.set() for redis-rs’s type inference.
• TxError allows you to return any type in TxError::Abort for custom type handling.
• If the transaction fails due to an underlying redis error or serde tx will reflect this in the associated TxError::DbError or TxError::Serialization.

JSON helpers

Using the helpers from TODO allow you to turn this:

let json_string: String = con.get(key).await?;
let value: Type = serde_json::from_str(&json_string).unwrap;

let value: Type = con.json_get(key).await.unwrap();

Modules

converters

Macros

tx

Async Transactions

unwatch

watch

Enums

TxError

Represents the various ways a transaction can return early. It could be Aborted early due to some precondition failure. It could fail due to a Serialization error if you’re using any of the redis_utils::converters. Or if there is an underlying RedisError.