limithandler: Refactor package to not use global state

The limithandler package uses global variables to both track Prometheus
metrics and to handle its configuration. Especially the latter is really
fragile, where we need to set up state of the limithandler in various
places by calling global functions.

Fix this by making the `LimiterMiddleware` self-contained, where it
hosts all configuration as well as the Prometheus metrics.

2 files changed, 3 insertions, 2 deletions

diff --git a/cmd/gitaly-ssh/auth_test.go b/cmd/gitaly-ssh/auth_test.go
index c15901765..3dd82bea1 100644
--- a/cmd/gitaly-ssh/auth_test.go
+++ b/cmd/gitaly-ssh/auth_test.go
@@ -155,7 +155,7 @@ func runServer(t *testing.T, secure bool, cfg config.Cfg, connectionType string,
 		t, gitlab.MockAllowed, gitlab.MockPreReceive, gitlab.MockPostReceive,
 	), cfg)
 	gitCmdFactory := git.NewExecCommandFactory(cfg)
-	limitHandler := limithandler.New(limithandler.LimitConcurrencyByRepo)
+	limitHandler := limithandler.New(cfg, limithandler.LimitConcurrencyByRepo)
 	diskCache := cache.New(cfg, locator)
 	srv, err := server.New(secure, cfg, testhelper.NewDiscardingLogEntry(t), registry, diskCache, limitHandler)
 	require.NoError(t, err)
diff --git a/cmd/gitaly/main.go b/cmd/gitaly/main.go
index 2699fa5de..8b0e0da6e 100644
--- a/cmd/gitaly/main.go
+++ b/cmd/gitaly/main.go
@@ -192,7 +192,8 @@ func run(cfg config.Cfg) error {
 		return fmt.Errorf("disk cache walkers: %w", err)
 	}
 
-	limitHandler := limithandler.New(limithandler.LimitConcurrencyByRepo)
+	limitHandler := limithandler.New(cfg, limithandler.LimitConcurrencyByRepo)
+	prometheus.MustRegister(limitHandler)
 
 	gitalyServerFactory := server.NewGitalyServerFactory(cfg, glog.Default(), registry, diskCache, limitHandler)
 	defer gitalyServerFactory.Stop()