Maint: healthcheck package interface rework

- return concrete struct type
- Add compilation checks for implementations

internal/cli/healthcheck.go

@@ -31,10 +31,10 @@ func (c *CLI) HealthCheck(ctx context.Context, env params.Env,
 
 	const timeout = 10 * time.Second
 	httpClient := &http.Client{Timeout: timeout}
-	healthchecker := healthcheck.NewChecker(httpClient)
+	client := healthcheck.NewClient(httpClient)
 	ctx, cancel := context.WithTimeout(ctx, timeout)
 	defer cancel()
 
 	url := "http://127.0.0.1:" + port
-	return healthchecker.Check(ctx, url)
+	return client.Check(ctx, url)
 }

internal/healthcheck/client.go

@@ -12,26 +12,28 @@ var (
 	ErrHTTPStatusNotOK = errors.New("HTTP response status is not OK")
 )
 
+var _ Checker = (*Client)(nil)
+
 type Checker interface {
 	Check(ctx context.Context, url string) error
 }
 
-type checker struct {
+type Client struct {
 	httpClient *http.Client
 }
 
-func NewChecker(httpClient *http.Client) Checker {
-	return &checker{
+func NewClient(httpClient *http.Client) *Client {
+	return &Client{
 		httpClient: httpClient,
 	}
 }
 
-func (h *checker) Check(ctx context.Context, url string) error {
+func (c *Client) Check(ctx context.Context, url string) error {
 	request, err := http.NewRequestWithContext(ctx, http.MethodGet, url, nil)
 	if err != nil {
 		return err
 	}
-	response, err := h.httpClient.Do(request)
+	response, err := c.httpClient.Do(request)
 	if err != nil {
 		return err
 	}

internal/healthcheck/health.go

@@ -9,7 +9,7 @@ import (
 	"time"
 )
 
-func (s *server) runHealthcheckLoop(ctx context.Context, done chan<- struct{}) {
+func (s *Server) runHealthcheckLoop(ctx context.Context, done chan<- struct{}) {
 	defer close(done)
 
 	s.openvpn.healthyTimer = time.NewTimer(s.openvpn.healthyWait)

internal/healthcheck/openvpn.go

@@ -5,9 +5,16 @@ import (
 	"time"
 
 	"github.com/qdm12/gluetun/internal/constants"
+	"github.com/qdm12/gluetun/internal/openvpn"
 )
 
-func (s *server) onUnhealthyOpenvpn(ctx context.Context) {
+type openvpnHealth struct {
+	looper       openvpn.Looper
+	healthyWait  time.Duration
+	healthyTimer *time.Timer
+}
+
+func (s *Server) onUnhealthyOpenvpn(ctx context.Context) {
 	s.logger.Info("program has been unhealthy for " +
 		s.openvpn.healthyWait.String() + ": restarting OpenVPN")
 	_, _ = s.openvpn.looper.ApplyStatus(ctx, constants.Stopped)

internal/healthcheck/run.go

@@ -0,0 +1,40 @@
+package healthcheck
+
+import (
+	"context"
+	"errors"
+	"net/http"
+	"time"
+)
+
+func (s *Server) Run(ctx context.Context, done chan<- struct{}) {
+	defer close(done)
+
+	loopDone := make(chan struct{})
+	go s.runHealthcheckLoop(ctx, loopDone)
+
+	server := http.Server{
+		Addr:    s.config.ServerAddress,
+		Handler: s.handler,
+	}
+	serverDone := make(chan struct{})
+	go func() {
+		defer close(serverDone)
+		<-ctx.Done()
+		const shutdownGraceDuration = 2 * time.Second
+		shutdownCtx, cancel := context.WithTimeout(context.Background(), shutdownGraceDuration)
+		defer cancel()
+		if err := server.Shutdown(shutdownCtx); err != nil {
+			s.logger.Error("failed shutting down: " + err.Error())
+		}
+	}()
+
+	s.logger.Info("listening on " + s.config.ServerAddress)
+	err := server.ListenAndServe()
+	if err != nil && !errors.Is(ctx.Err(), context.Canceled) {
+		s.logger.Error(err.Error())
+	}
+
+	<-loopDone
+	<-serverDone
+}

internal/healthcheck/server.go

@@ -2,21 +2,20 @@ package healthcheck
 
 import (
 	"context"
-	"errors"
 	"net"
-	"net/http"
-	"time"
 
 	"github.com/qdm12/gluetun/internal/configuration"
 	"github.com/qdm12/gluetun/internal/openvpn"
 	"github.com/qdm12/golibs/logging"
 )
 
-type Server interface {
+var _ ServerRunner = (*Server)(nil)
+
+type ServerRunner interface {
 	Run(ctx context.Context, done chan<- struct{})
 }
 
-type server struct {
+type Server struct {
 	logger   logging.Logger
 	handler  *handler
 	resolver *net.Resolver
@@ -24,15 +23,9 @@ type server struct {
 	openvpn  openvpnHealth
 }
 
-type openvpnHealth struct {
-	looper       openvpn.Looper
-	healthyWait  time.Duration
-	healthyTimer *time.Timer
-}
-
 func NewServer(config configuration.Health,
-	logger logging.Logger, openvpnLooper openvpn.Looper) Server {
-	return &server{
+	logger logging.Logger, openvpnLooper openvpn.Looper) *Server {
+	return &Server{
 		logger:   logger,
 		handler:  newHandler(logger),
 		resolver: net.DefaultResolver,
@@ -43,35 +36,3 @@ func NewServer(config configuration.Health,
 		},
 	}
 }
-
-func (s *server) Run(ctx context.Context, done chan<- struct{}) {
-	defer close(done)
-
-	loopDone := make(chan struct{})
-	go s.runHealthcheckLoop(ctx, loopDone)
-
-	server := http.Server{
-		Addr:    s.config.ServerAddress,
-		Handler: s.handler,
-	}
-	serverDone := make(chan struct{})
-	go func() {
-		defer close(serverDone)
-		<-ctx.Done()
-		const shutdownGraceDuration = 2 * time.Second
-		shutdownCtx, cancel := context.WithTimeout(context.Background(), shutdownGraceDuration)
-		defer cancel()
-		if err := server.Shutdown(shutdownCtx); err != nil {
-			s.logger.Error("failed shutting down: " + err.Error())
-		}
-	}()
-
-	s.logger.Info("listening on " + s.config.ServerAddress)
-	err := server.ListenAndServe()
-	if err != nil && !errors.Is(ctx.Err(), context.Canceled) {
-		s.logger.Error(err.Error())
-	}
-
-	<-loopDone
-	<-serverDone
-}