CRUD Operations Using GOA Framework — Part I

Build your api’s using GOA framework

Before we begin let’s understand what is GOA ?

• Goa is framework for developing API’s and microservices in Go.
• Goa completely relies on code generation which reduces the need for repetitive coding.
• Goa is design based framework, having said that “Design is the single source of truth” and from which both design and docs are derived.
• You can find more detailed information here

Moving on let’s get started ….

NOTE:
Part-I just includes adding services for adding records and showing the added records!

Create a new project under your home directory

mkdir -p book/design
cd book
go mod init book

Next make sure the Goa module is installed and up-to-date:

go get -u goa.design/goa/v3
go get -u goa.design/goa/v3/...

Now let’s start with design to create a record of book and list all the books

Create and open the file $HOME/book/design/design.go and paste the following code …

Further let’s create and add type for book, open the file $HOME/book/design/type.go and paste the following code

Now let’s write methods for create and list by updating the design.go file

Now as we have the design for our service let’s run the goa gen command to generated the code. Since our design package was created under the book module the command line is

goa gen book/design

The generated file should look like this

gen
├── book
│   ├── client.go
│   ├── endpoints.go
│   ├── service.go
│   └── views
│       └── view.go
└── http
    ├── book
    │   ├── client
    │   │   ├── client.go
    │   │   ├── cli.go
    │   │   ├── encode_decode.go
    │   │   ├── paths.go
    │   │   └── types.go
    │   └── server
    │       ├── encode_decode.go
    │       ├── paths.go
    │       ├── server.go
    │       └── types.go
    ├── cli
    │   └── book
    │       └── cli.go
    ├── openapi3.json
    ├── openapi3.yaml
    ├── openapi.json
    └── openapi.yaml

We can now run the goa example command to generate a basic implementation of the service along with buildable server files that spins up goroutines to start a HTTP.

goa example book/design

The goa example command creates the following files

├── book.go
├── cmd
│   ├── book
│   │   ├── http.go
│   │   └── main.go
│   └── book-cli
│       ├── http.go
│       └── main.go

The auto-generated book.go file would be similar to

Edit the file book.go and implement the create and list method. Copy and replace the following code in book.go

The generated server are built and run as follows:

go build ./cmd/book

# Run the server
./book
[bookapi] 18:02:39 HTTP "Create" mounted on POST /
[bookapi] 18:02:39 HTTP "List" mounted on GET /books
[bookapi] 18:02:39 HTTP server listening on "localhost:8000"

Let’s add a record using Postman by making a POST api call

To list the records of books one can simply make an api call with method GETas follows

Let’s create services for updating and deleting in Part-II

You can find the source code here