transaction

Documentation

Overview

Package transaction provides utilities for wrapping operations in a transaction. Upon transaction failure, changes are expected to be rolled back, and, upon transaction success, changes are committed.

A transaction object contains a list of contexts, each containing their own key (string). Keys should be unique for each transaction type. For example, given a postgres connection and a file service, a TransactionContext can be created for each, satisfying the Context interface. This transaction context can be directly registered into the Transaction.Context map. Then, define a method such as `Use(tx *Transaction)` which attempts to retrieve the context from the tx.Context map. If it doesn't exist, create a new one.

func GetCustomTransactionContext(tx *Transaction, args AnyArgsNeeded) *CustomTransactionContext{
   m, ok := tx.Contexts["CustomTransactionContext"]
   if ok {
       v, ok := m.(*CustomTransactionContext)
       if ok {
          return v
       }
   }

   v := CreateTransactionContext(args AnyArgsNeeded)
   tx.Contexts["CustomTransactionContext"] = v
   return v
}

A helper method GetContext is created to help with this logic.

Index

• func GetContext[T Context](tx *Transaction, key string, create func() T) T
• func Tx(fn func(tx *Transaction) error) error
• type Context
• type TestContext
  • func (t *TestContext) Commit()
  • func (t *TestContext) Rollback()
• type Transaction
  • func (t *Transaction) Commit()
  • func (t *Transaction) Rollback()

Functions

func GetContext

func GetContext[T Context](tx *Transaction, key string, create func() T) T

GetContext is a helper method to retrieve a context of a certain type from a transaction, associated with a specific key. If it does not exist, it will be created through the provided create method.

func Tx

func Tx(fn func(tx *Transaction) error) error

Tx provides the transaction for wrapping of functions. Functions that wish to sue the function should take in the Transaction that is passed as the argument.

Types

type Context

type Context interface {
	// Rollback are operations that need to be done to clean-up on failure.
	Rollback()

	// Commit solidifies the resultant operations.
	Commit()
}

Context defines a group of transactions in the same type of service (e.g., postgers; s3) which can Rollback or Commit.

type TestContext

type TestContext struct {
	mock.Mock
}

TestContext is a test transaction context. It implement Context.

func (*TestContext) Commit

func (t *TestContext) Commit()

Commit solidifies the resultant operations.

func (*TestContext) Rollback

func (t *TestContext) Rollback()

Rollback are operations that need to be done to clean-up on failure.

type Transaction

type Transaction struct {
	// Contexts are what is used to retrieve any objects required to be stored within the
	Contexts map[string]Context
}

Transaction defines a single transaction

func (*Transaction) Commit

func (t *Transaction) Commit()

func (*Transaction) Rollback

func (t *Transaction) Rollback()