Take 2 for fix the limit settings (#519)

* Revert "Make sure the default for EnforceMetricName is 

 (#518)"

This reverts commit 199746a1.

* Fix overrides unmarshalling properly

Signed-off-by: Goutham Veeramachaneni <gouthamve@gmail.com>

cmd/loki/loki-local-config.yaml

@@ -27,3 +27,6 @@ storage_config:
 
   filesystem:
     directory: /tmp/loki/chunks
+
+limits_config:
+  enforce_metric_name: false

cmd/loki/main.go

@@ -14,6 +14,7 @@ import (
 
 	"github.com/cortexproject/cortex/pkg/util"
 	"github.com/cortexproject/cortex/pkg/util/flagext"
+	"github.com/cortexproject/cortex/pkg/util/validation"
 )
 
 func init() {
@@ -29,8 +30,14 @@ func main() {
 	flagext.RegisterFlags(&cfg)
 	flag.Parse()
 
-	// The flags set the EnforceMetricName to be true, but in loki it _should_ be false.
-	cfg.LimitsConfig.EnforceMetricName = false
+	// LimitsConfig has a customer UnmarshalYAML that will set the defaults to a global.
+	// This global is set to the config passed into the last call to `NewOverrides`. If we don't
+	// call it atleast once, the defaults are set to an empty struct.
+	// We call it with the flag values so that the config file unmarshalling only overrides the values set in the config.
+	if _, err := validation.NewOverrides(cfg.LimitsConfig); err != nil {
+		level.Error(util.Logger).Log("msg", "error loading limits", "err", err)
+		os.Exit(1)
+	}
 
 	util.InitLogger(&cfg.Server)
 

production/helm/loki/values.yaml

@@ -37,6 +37,8 @@ config:
       #     prefix: ""
       #     httpclienttimeout: "20s"
       #     consistentreads: true
+  limits_config:
+    enforce_metric_name: false
   schema_config:
     configs:
     - from: 0

production/ksonnet/loki/config.libsonnet

@@ -29,6 +29,10 @@
         grpc_server_max_recv_msg_size: 1024 * 1024 * 64,
       },
 
+      limits_config: {
+        enforce_metric_name: false,
+      },
+
       ingester: {
         chunk_idle_period: '15m',