nero

README

Nero

A library for generating the repository layer code. Please see this blog post for more details.

Installation

$ go get github.com/sf9v/nero

Example

See the integration test for a more complete example.

import (
    "database/sql"

    _ "github.com/lib/pq"

    // import the generated package
    "github.com/sf9v/nero-example/repository"
)

func main() {
    dsn := "postgres://postgres:postgres@localhost:5432/postgres?sslmode=disable"
    db, err := sql.Open("postgres", dsn)
    ...

    // initialize a new postgres repository
    repo := repository.NewPostgresRepository(db).Debug()

    // create a product
    productID, err := repo.Create(
        context.Background(), 
        repository.NewCreator().Name("Product 1"),
    )
    ...	

    // query the product
    product, err := repo.QueryOne(
        context.Background(), 
        repository.NewQueryer().
            Where(repository.IDEq(product1ID)),
    )
    ...

    // update the product
    now := time.Now()
    _, err = repo.Update(
        context.Background(), 
        repository.NewUpdater().
            Name("Updated Product 1").
            UpdatedAt(&now).
            Where(repository.IDEq(product1ID),
        ),
    )
    ...
    
    // delete the product
    _, err = repo.Delete(
        context.Background(), 
        repository.NewDeleter().
            Where(repository.IDEq(product1ID),
        ),
    )
    ...
}

Motivation

We heavily use the repository pattern in our codebases and we often write our queries manually. It becomes tedious and repetitive as we have more tables/models to maintain. So, we decided to experiment on creating this project to generate our repository layer automatically.

Goals

• Decouple implementation details from the Repository interface
• Easy integration with existing codebase
• Minimal API

Supported back-ends

Currently, we have official support for PostgreSQL, which is what we mainly use. Other back-ends shall be supported as time permits.

Back-end	Library
PostgreSQL	lib/pq
SQLite (soon)
MySQL/MariaDB (soon)
MongoDB ???

If your your back-end is not yet supported, you can implement your own custom back-end.

Custom back-ends

Implementing a custom back-end is very easy. In fact, you don't have to use the official back-ends. You can implement custom back-ends (ClickHouse, Cassandra, CouchDB , Badger, H2, etc.) by implementing the Templater interface. This interface is specifically created to support extensibility and customisability.

You can refer to the official postgres template and this example schema.

Standing on the shoulders of giants

This project wouldn't be possible with the amazing open-source projects it was built on.

• Masterminds/squirrel - Fluent SQL generation in golang
• lib/pq - Pure Go Postgres driver for database/sql
• pkg/errors - Simple error handling primitives
• hashicorp/multierror - A Go (golang) package for representing a list of errors as a single error.
• jinzhu/inflection - Pluralizes and singularizes English nouns
• stretchr/testify - A toolkit with common assertions and mocks that plays nicely with the standard library

Also, the following have a huge influence on this project and deserves most of the credits:

• ent. An entity framework for Go. Simple, yet powerful ORM for modeling and querying data.
• SQLBoiler is a tool to generate a Go ORM tailored to your database schema.

Contributing

Any suggestions and ideas on how to improve this library are very much welcome! Please feel free to open an issue or by making a pull request.

Documentation

Index

• func NewFuncMap() template.FuncMap
• func ParseTemplater(tmpl Templater) (*template.Template, error)
• type Column
  • func (c *Column) CanHavePreds() bool
  • func (c *Column) FieldName() string
  • func (c *Column) Identifier() string
  • func (c *Column) IdentifierPlural() string
  • func (c *Column) IsArray() bool
  • func (c *Column) IsAuto() bool
  • func (c *Column) IsComparable() bool
  • func (c *Column) IsNillable() bool
  • func (c *Column) IsOptional() bool
  • func (c *Column) IsValueScanner() bool
  • func (c *Column) Name() string
  • func (c *Column) TypeInfo() *mira.TypeInfo
• type ColumnBuilder
  • func NewColumnBuilder(name string, v interface{}) *ColumnBuilder
  • func (cb *ColumnBuilder) Auto() *ColumnBuilder
  • func (cb *ColumnBuilder) Build() *Column
  • func (cb *ColumnBuilder) Comparable() *ColumnBuilder
  • func (cb *ColumnBuilder) Optional() *ColumnBuilder
  • func (cb *ColumnBuilder) StructField(structField string) *ColumnBuilder
• type ErrRequiredField
  • func NewErrRequiredField(field string) *ErrRequiredField
  • func (e *ErrRequiredField) Error() string
• type Logger
• type PostgresTemplate
  • func NewPostgresTemplate() *PostgresTemplate
  • func (t *PostgresTemplate) Filename() string
  • func (t *PostgresTemplate) Template() string
  • func (t *PostgresTemplate) WithFilename(filename string) *PostgresTemplate
• type SQLRunner
• type Schema
  • func (s *Schema) Collection() string
  • func (s *Schema) Columns() []*Column
  • func (s *Schema) Identity() *Column
  • func (s *Schema) Imports() []string
  • func (s *Schema) PkgName() string
  • func (s *Schema) Templaters() []Templater
  • func (s *Schema) TypeIdentifier() string
  • func (s *Schema) TypeIdentifierPlural() string
  • func (s *Schema) TypeInfo() *mira.TypeInfo
  • func (s *Schema) TypeName() string
  • func (s *Schema) TypeNamePlural() string
• type SchemaBuilder
  • func NewSchemaBuilder(v interface{}) *SchemaBuilder
  • func (sb *SchemaBuilder) Build() *Schema
  • func (sb *SchemaBuilder) Collection(collection string) *SchemaBuilder
  • func (sb *SchemaBuilder) Columns(columns ...*Column) *SchemaBuilder
  • func (sb *SchemaBuilder) Identity(column *Column) *SchemaBuilder
  • func (sb *SchemaBuilder) PkgName(pkgName string) *SchemaBuilder
  • func (sb *SchemaBuilder) Templates(templaters ...Templater) *SchemaBuilder
• type Templater
• type Tx
• type ValueScanner

Functions

func NewFuncMap

func NewFuncMap() template.FuncMap

NewFuncMap returns a tempalte func map

func ParseTemplater

func ParseTemplater(tmpl Templater) (*template.Template, error)

ParseTemplater parses the repository templater

Types

type Column

type Column struct {
	// contains filtered or unexported fields
}

Column is a column

func (*Column) CanHavePreds

func (c *Column) CanHavePreds() bool

CanHavePreds returns true if column can have predicate functions

func (*Column) FieldName

func (c *Column) FieldName() string

FieldName returns the field name

func (*Column) Identifier

func (c *Column) Identifier() string

Identifier returns the lower-camelized field name

func (*Column) IdentifierPlural

func (c *Column) IdentifierPlural() string

IdentifierPlural returns the plural form of lower-camelized field name

func (*Column) IsArray

func (c *Column) IsArray() bool

IsArray returns true if column is an array or a slice

func (*Column) IsAuto

func (c *Column) IsAuto() bool

IsAuto returns the auto flag

func (*Column) IsComparable

func (c *Column) IsComparable() bool

IsComparable returns the column comparable flag

func (*Column) IsNillable

func (c *Column) IsNillable() bool

IsNillable returns true if the column is nillable

func (*Column) IsOptional

func (c *Column) IsOptional() bool

IsOptional returns the optional flag

func (*Column) IsValueScanner

func (c *Column) IsValueScanner() bool

IsValueScanner returns true if column implements value scanner

func (*Column) Name

func (c *Column) Name() string

Name returns the column name

func (*Column) TypeInfo

func (c *Column) TypeInfo() *mira.TypeInfo

TypeInfo returns the type info

type ColumnBuilder

type ColumnBuilder struct {
	// contains filtered or unexported fields
}

ColumnBuilder is a column

func NewColumnBuilder

func NewColumnBuilder(name string, v interface{}) *ColumnBuilder

NewColumnBuilder returns a ColumnBuilder

func (*ColumnBuilder) Auto

func (cb *ColumnBuilder) Auto() *ColumnBuilder

Auto sets the column as auto-filled

func (*ColumnBuilder) Build

func (cb *ColumnBuilder) Build() *Column

Build builds the column

func (*ColumnBuilder) Comparable

func (cb *ColumnBuilder) Comparable() *ColumnBuilder

Comparable sets the column as comparable

func (*ColumnBuilder) Optional

func (cb *ColumnBuilder) Optional() *ColumnBuilder

Optional sets the column as optional

func (*ColumnBuilder) StructField

func (cb *ColumnBuilder) StructField(structField string) *ColumnBuilder

StructField sets the struct field name override. This is useful when the inferred struct field is different from the actual field e.g. The struct field of the model is "ID" but being referred to as "Id" in the generated code

type ErrRequiredField

type ErrRequiredField struct {
	// contains filtered or unexported fields
}

ErrRequiredField is a required field error

func NewErrRequiredField

func NewErrRequiredField(field string) *ErrRequiredField

NewErrRequiredField returns an ErrFieldRequired error

func (*ErrRequiredField) Error

func (e *ErrRequiredField) Error() string

type Logger

type Logger interface {
	Printf(string, ...interface{})
}

Logger is a logger interface

type PostgresTemplate

type PostgresTemplate struct {
	// contains filtered or unexported fields
}

PostgresTemplate is the template for generating a postgres repository

func NewPostgresTemplate

func NewPostgresTemplate() *PostgresTemplate

NewPostgresTemplate returns a new PostgresTemplate

func (*PostgresTemplate) Filename

func (t *PostgresTemplate) Filename() string

Filename returns the filename

func (*PostgresTemplate) Template

func (t *PostgresTemplate) Template() string

Content returns the template content

func (*PostgresTemplate) WithFilename

func (t *PostgresTemplate) WithFilename(filename string) *PostgresTemplate

WithFilename overrides the default filename

type SQLRunner

type SQLRunner interface {
	Query(string, ...interface{}) (*sql.Rows, error)
	QueryContext(context.Context, string, ...interface{}) (*sql.Rows, error)
	QueryRow(string, ...interface{}) *sql.Row
	QueryRowContext(context.Context, string, ...interface{}) *sql.Row
	Exec(string, ...interface{}) (sql.Result, error)
	ExecContext(context.Context, string, ...interface{}) (sql.Result, error)
}

SQLRunner is the standard sql interface runner

type Schema

type Schema struct {
	// contains filtered or unexported fields
}

Schema is a schema used for generating the repository

func (*Schema) Collection

func (s *Schema) Collection() string

Collection returns the collection

func (*Schema) Columns

func (s *Schema) Columns() []*Column

Columns returns the columns

func (*Schema) Identity

func (s *Schema) Identity() *Column

Identity returns the identity column

func (*Schema) Imports

func (s *Schema) Imports() []string

Imports returns the pkg imports

func (*Schema) PkgName

func (s *Schema) PkgName() string

PkgName returns the pkg name

func (*Schema) Templaters

func (s *Schema) Templaters() []Templater

Templaters returns the templaters

func (*Schema) TypeIdentifier

func (s *Schema) TypeIdentifier() string

TypeIdentifier returns the type identifier

func (*Schema) TypeIdentifierPlural

func (s *Schema) TypeIdentifierPlural() string

TypeIdentifierPlural returns the plural form of type identifier

func (*Schema) TypeInfo

func (s *Schema) TypeInfo() *mira.TypeInfo

TypeInfo returns the type info

func (*Schema) TypeName

func (s *Schema) TypeName() string

TypeName returns the type name

func (*Schema) TypeNamePlural

func (s *Schema) TypeNamePlural() string

type SchemaBuilder

type SchemaBuilder struct {
	// contains filtered or unexported fields
}

SchemaBuilder is schema builder

func NewSchemaBuilder

func NewSchemaBuilder(v interface{}) *SchemaBuilder

NewSchemaBuilder takes a model struct value and returns a SchemaBuilder

func (*SchemaBuilder) Build

func (sb *SchemaBuilder) Build() *Schema

Build builds the schema

func (*SchemaBuilder) Collection

func (sb *SchemaBuilder) Collection(collection string) *SchemaBuilder

Collection sets the collection

func (*SchemaBuilder) Columns

func (sb *SchemaBuilder) Columns(columns ...*Column) *SchemaBuilder

Columns sets the columns

func (*SchemaBuilder) Identity

func (sb *SchemaBuilder) Identity(column *Column) *SchemaBuilder

Identity sets the identity column

func (*SchemaBuilder) PkgName

func (sb *SchemaBuilder) PkgName(pkgName string) *SchemaBuilder

PkgName sets the pkg name

func (*SchemaBuilder) Templates

func (sb *SchemaBuilder) Templates(templaters ...Templater) *SchemaBuilder

Templates sets the templates

type Templater

type Templater interface {
	// Filename is the filename of the generated file
	Filename() string
	// Template is template for generating the repository implementation
	Template() string
}

Templater is an interface that wraps the Filename and Template method

type Tx

type Tx interface {
	Commit() error
	Rollback() error
}

Tx is an interface that wraps the Commit and Rollback method

type ValueScanner

type ValueScanner interface {
	driver.Valuer
	sql.Scanner
}

ValueScanner is the composition of driver.Valuer and sql.Scanner interfaces