goshort/cmd/healthcheck/healthcheck.go

package healthcheckcmd

import (
	"context"
	"errors"
	"flag"
	"fmt"
	"log/slog"
	"net"
	"net/http"
	"net/url"

	"git.maronato.dev/maronato/goshort/cmd/shared"
	"git.maronato.dev/maronato/goshort/internal/config"
	"git.maronato.dev/maronato/goshort/internal/util/logging"
	"github.com/peterbourgon/ff/v3/ffcli"
)

var ErrFailedHealthCheck = errors.New("healthcheck failed")

func New(cfg *config.Config) *ffcli.Command {
	// Create the flagset and register the flags.
	fs := flag.NewFlagSet("goshort healthcheck", flag.ContinueOnError)

	shared.RegisterBaseFlags(fs, cfg)

	// Create the command and options
	cmd := shared.NewCommand(cfg, exec)
	opts := shared.NewSharedCmdOptions()

	// Return the ffcli command.
	return &ffcli.Command{
		Name:       "healthcheck",
		ShortUsage: "goshort healthcheck [flags]",
		ShortHelp:  "Calls the healthcheck endpoint of the server",
		FlagSet:    fs,
		Exec:       cmd.Exec,
		Options:    opts,
	}
}

// exec makes a request to the healthcheck endpoint.
// If the request fails, return an error
// Otherwise, return nil.
func exec(ctx context.Context, cfg *config.Config) error {
	l := logging.FromCtx(ctx)
	l.Debug("Executing healthcheck command", slog.Any("config", cfg))

	addr := url.URL{
		Host:   net.JoinHostPort(cfg.Host, cfg.Port),
		Scheme: "http",
		Path:   "/healthz",
	}

	req, err := http.NewRequestWithContext(ctx, http.MethodGet, addr.String(), http.NoBody)
	if err != nil {
		return fmt.Errorf("error creating request: %w", err)
	}

	resp, err := http.DefaultClient.Do(req)
	if err != nil {
		return fmt.Errorf("error making request: %w", err)
	}
	defer resp.Body.Close()

	if resp.StatusCode != http.StatusOK {
		return fmt.Errorf(
			"healthcheck endpoint returned status code %d: %w",
			resp.StatusCode,
			ErrFailedHealthCheck,
		)
	}

	return nil
}