Configuration

The development environment is built using Docker, which offers a portable and consistent way to manage dependencies and run the application.

To modify the configuration, make changes to the following files:

• Dockerfile - This file defines the Docker image for the application. It manages dependencies, builds the application, and exposes the necessary port.

• go.mod - This file specifies the Golang dependencies used in the project.

• app.go - This file contains the main application logic, including the HTTP server configuration.

Dockerfile

The Dockerfile defines the steps for building a Docker image.

Configuration Options:

1. FROM golang:1.21-alpine AS builder - This line specifies the base Docker image used for building the application. You can modify this line to change the Golang version or the base image.

2. EXPOSE 8080 - This line exposes port 8080 on the Docker container, allowing external connections to the application.

3. CMD ["./myapp"] - This line sets the command to run when the Docker container starts. It runs the compiled myapp executable.

Example:

# First stage: build the application
FROM golang:1.21-alpine AS builder

# Set the working directory
WORKDIR /app

# Copy go.mod
COPY go.mod go.sum ./

# Download dependencies and generate go.sum
RUN go mod download && go mod tidy

# Copy the rest of the application code
COPY . .

# Build the application
RUN go build -o myapp

# Second stage: create the runtime image
FROM alpine:latest

# Set the working directory
WORKDIR /root/

# Copy the built application from the builder stage
COPY --from=builder /app/myapp .

# Expose port 8080 to the outside world
EXPOSE 8080

# Command to run the executable
CMD ["./myapp"]

go.mod

The go.mod file manages the Golang dependencies for the project.

Configuration Options:

1. module myapp - This line specifies the Golang module name for the project, which impacts the output of go build.

2. go 1.18 - This line specifies the required Go version for the project.

3. require github.com/gorilla/mux v1.8.0 - This line defines the dependencies used by the project, including the version.

Example:

module myapp

go 1.18

require github.com/gorilla/mux v1.8.0

app.go

The app.go file contains the application logic, including the HTTP server configuration.

Configuration Options:

1. Addr: ":8080" - This line sets the address and port for the HTTP server to listen on.

2. ReadTimeout: 15 * time.Second - This line sets the read timeout for the HTTP server.

3. WriteTimeout: 15 * time.Second - This line sets the write timeout for the HTTP server.

4. IdleTimeout: 60 * time.Second - This line sets the idle timeout for the HTTP server.

Example:

func main() {
    r := mux.NewRouter()
    r.HandleFunc("/", HelloWorld).Methods("GET")

    server := &http.Server{
        Addr:         ":8080",
        Handler:      r,
        ReadTimeout:  15 * time.Second,
        WriteTimeout: 15 * time.Second,
        IdleTimeout:  60 * time.Second,
    }

    go func() {
        fmt.Println("Server started at :8080")
        if err := server.ListenAndServe(); err != nil && err != http.ErrServerClosed {
            log.Fatalf("Could not listen on :8080: %v\n", err)
        }
    }()

    // Wait for an interrupt signal to gracefully shutdown the server
    c := make(chan os.Signal, 1)
    signal.Notify(c, os.Interrupt)

    <-c

    ctx, cancel := context.WithTimeout(context.Background(), 15*time.Second)
    defer cancel()
    server.Shutdown(ctx)

    log.Println("shutting down")
    os.Exit(0)
}