Maint: add missing interface compilation checks

internal/httpproxy/loop.go

@@ -13,6 +13,8 @@ import (
 	"github.com/qdm12/golibs/logging"
 )
 
+var _ Looper = (*Loop)(nil)
+
 type Looper interface {
 	Runner
 	loopstate.Getter

internal/loopstate/state.go

@@ -6,6 +6,8 @@ import (
 	"github.com/qdm12/gluetun/internal/models"
 )
 
+var _ Manager = (*State)(nil)
+
 type Manager interface {
 	Locker
 	Getter

internal/openvpn/loop.go

@@ -15,6 +15,8 @@ import (
 	"github.com/qdm12/golibs/logging"
 )
 
+var _ Looper = (*Loop)(nil)
+
 type Looper interface {
 	Runner
 	loopstate.Getter

internal/publicip/fetch.go

@@ -12,6 +12,8 @@ import (
 	"strings"
 )
 
+var _ Fetcher = (*Fetch)(nil)
+
 type Fetcher interface {
 	FetchPublicIP(ctx context.Context) (ip net.IP, err error)
 }