README
¶
🌮 yowrap 🌮
Lightweight Go package designed to effortlessly wrap the Yo package for enhanced functionality.
Context
Yo is a command-line tool that generates Go code from SQL DDL files. The generated code is used to interact with Google Cloud Spanner databases, representing the table and a set of methods to interact with the table.
Yo is a great tool to generate the boilerplate code needed to interact with a Google Cloud Spanner database. However, the generated code is not intended to be modified by the user, as it is overwritten every time the yo tool is executed. This pkg is designed to extend the generated code functionality creating a more capable model.
This package is designed to be used in conjunction with the yo tool, not as a replacement.
See Yo for more information about the yo tool.
Features
- Commit transaction: This feature allows the client to commit a model transaction directly from the model instance without using the spanner.Mutation outside the model. Now, the model has the responsibility of writing the changes to the database.
- Custom model hooks: This feature allows the client to define custom hooks that will be executed before or after a specific method is called. This is useful for adding custom logic to the model methods.
- Inheric model methods: All the method signatures from the generated code are inherited by the model. This allows the client to call the generated methods directly from the model instance.
Usage
Use yowrap as a wrapper for the generated model but committing the transaction outside the model. This mantains the ability to use the generated methods-
package main
import (
"context"
"fmt"
"log"
"cloud.google.com/go/spanner"
"github.com/jferrl/yowrap"
)
func main() {
spannerClient, err := spanner.NewClient(ctx, "projects/my-project/instances/my-instance/databases/my-database")
if err != nil {
log.Fatalf("Failed to create a Spanner client: %v", err)
}
defer spannerClient.Close()
// Go struct generated by the yo tool
user := &User{
ID: 1,
Name: "John Doe",
Email: " [email protected]",
}
// Create a new user model
user := yowrap.NewModel(user)
mut := user.Insert(ctx)
_, err = spannerClient.Apply(ctx, []*spanner.Mutation{mut})
if err != nil {
log.Fatalf("Failed to apply the mutation: %v", err)
}
}
Use yowrap as a wrapper for the generated model and commit the transaction directly from the model.
package main
import (
"context"
"fmt"
"log"
"cloud.google.com/go/spanner"
"github.com/jferrl/yowrap"
)
func main() {
spannerClient, err := spanner.NewClient(ctx, "projects/my-project/instances/my-instance/databases/my-database")
if err != nil {
log.Fatalf("Failed to create a Spanner client: %v", err)
}
defer spannerClient.Close()
// Go struct generated by the yo tool
user := &User{
ID: 1,
Name: "John Doe",
Email: " [email protected]",
}
// Create a new user model
user := yowrap.NewModel(user, yowrap.WithSpannerClientOption(spannerClient))
// Commit the transaction
_, err = user.Apply(ctx, yowrap.Insert)
if err != nil {
log.Fatalf("Failed to insert and commit the user: %v", err)
}
}
Use yowrap with a custom hook.
package main
import (
"context"
"fmt"
"log"
"cloud.google.com/go/spanner"
"github.com/jferrl/yowrap"
)
func main() {
spannerClient, err := spanner.NewClient(ctx, "projects/my-project/instances/my-instance/databases/my-database")
if err != nil {
log.Fatalf("Failed to create a Spanner client: %v", err)
}
defer spannerClient.Close()
// Go struct generated by the yo tool
user := &User{
ID: 1,
Name: "John Doe",
Email: " [email protected]",
}
// Create a new user model
user := yowrap.NewModel(user, yowrap.WithSpannerClientOption(spannerClient))
// Add a custom hook
user.On(yowrap.BeforeInsert, func(_ context.Context, m *yowrap.Model[*user.User], _ *spanner.ReadWriteTransaction) error {
log.Println("Before insert")
return nil
})
// Commit the transaction
_, err = user.Apply(ctx, yowrap.Insert)
if err != nil {
log.Fatalf("Failed to insert and commit the user: %v", err)
}
}
License
Copyright 2024, jferrl
yowrap is released under the MIT license.
Documentation
¶
Overview ¶
Package yowrap provides a wrapper around the generated Yo model.
Index ¶
Constants ¶
This section is empty.
Variables ¶
var ErrNoClient = errors.New("no spanner client")
ErrNoClient is returned when the spanner client is not set.
Functions ¶
This section is empty.
Types ¶
type Hook ¶
type Hook int
Hook defines an action that can be executed during a mutation.
const ( // AfterInsert is executed when the Insert txn is called. AfterInsert Hook = iota + 1 // AfterUpdate is executed when the Update txn is called. AfterUpdate // AfterInsertOrUpdate is executed when the InsertOrUpdate txn is called. AfterInsertOrUpdate // AfterDelete is executed when the Delete txn is called. AfterDelete // BeforeInsert is executed before the Insert txn is called. BeforeInsert // BeforeUpdate is executed before the Update txn is called. BeforeUpdate // BeforeInsertOrUpdate is executed before the InsertOrUpdate txn is called. BeforeInsertOrUpdate // BeforeDelete is executed before the Delete txn is called. BeforeDelete )
type HookFunc ¶
HookFunc defines a function that could be executed during a transaction. The function should return an error if the transaction should be aborted. This funcions are used for create hooks that are executed before or after. This hooks are able to modify the model before the transaction is executed or create some new stuff during the ongoin transaction.
type Model ¶
type Model[T Yoable[T]] struct { Yoable[T] spanner.Client // contains filtered or unexported fields }
Model is a struct that embeds the generated model and implements the Yo interface.
type Mutation ¶
type Mutation int
Mutation defines a mutation that can be executed within spanner.
const ( // Insert is a mutation that inserts a row into a table. Insert Mutation = iota + 1 // Update is a mutation that updates a row in a table. Update // InsertOrUpdate is a mutation that inserts a row into a table. If the row // already exists, it updates it instead. Any column values not explicitly // written are preserved. InsertOrUpdate // Delete is a mutation that deletes a row from a table. Delete )
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