ref: add simple func to get map keys, drop lo dep

Stop being lazy and just implement a stupid simple key getter func.
Allows for dropping `lo`, which was pulled in entirely as a convenience
package.

go.mod

@@ -8,7 +8,6 @@ require (
 	github.com/prometheus/client_golang v1.20.4
 	github.com/prometheus/common v0.59.1
 	github.com/prometheus/exporter-toolkit v0.13.0
-	github.com/samber/lo v1.47.0
 	github.com/stretchr/testify v1.9.0
 	gopkg.in/ns1/ns1-go.v2 v2.12.1
 )

go.sum

@@ -50,8 +50,6 @@ github.com/prometheus/procfs v0.15.1 h1:YagwOFzUgYfKKHX6Dr+sHT7km/hxC76UB0leargg
 github.com/prometheus/procfs v0.15.1/go.mod h1:fB45yRUv8NstnjriLhBQLuOUt+WW4BsoGhij/e3PBqk=
 github.com/rogpeppe/go-internal v1.10.0 h1:TMyTOH3F/DB16zRVcYyreMH6GnZZrwQVAoYjRBZyWFQ=
 github.com/rogpeppe/go-internal v1.10.0/go.mod h1:UQnix2H7Ngw/k4C5ijL5+65zddjncjaFoBhdsK/akog=
-github.com/samber/lo v1.47.0 h1:z7RynLwP5nbyRscyvcD043DWYoOcYRv3mV8lBeqOCLc=
-github.com/samber/lo v1.47.0/go.mod h1:RmDH9Ct32Qy3gduHQuKJ3gW1fMHAnE/fAzQuf6He5cU=
 github.com/stretchr/objx v0.1.0/go.mod h1:HFkY916IF+rwdDfMAkV7OtwuqBVzrE8GR6GFx+wExME=
 github.com/stretchr/objx v0.4.0/go.mod h1:YvHI0jy2hoMjB+UWwv71VJQ9isScKT/TqJzVSSt89Yw=
 github.com/stretchr/objx v0.5.0/go.mod h1:Yh+to48EsGEfYuaHDzXPcE3xhTkx73EhmCGUpEOglKo=

pkg/servicediscovery/sd.go

@@ -26,7 +26,6 @@ import (
 	"time"
 
 	promModel "github.com/prometheus/common/model"
-	"github.com/samber/lo"
 	api "gopkg.in/ns1/ns1-go.v2/rest"
 	"gopkg.in/ns1/ns1-go.v2/rest/model/account"
 	"gopkg.in/ns1/ns1-go.v2/rest/model/data"
@@ -103,7 +102,7 @@ func metaAsPrometheusMetaLabel(meta *data.Meta, innerDelim, outerDelim string) s
 
 	fmt.Fprintf(&builder, "meta[%s", innerDelim)
 
-	metaMapKeys := lo.Keys(metaMap)
+	metaMapKeys := getMapKeys(metaMap)
 	sort.Strings(metaMapKeys)
 	for _, key := range metaMapKeys {
 		fmt.Fprintf(&builder, "%s=%v%s", key, metaMap[key], innerDelim)
@@ -152,7 +151,7 @@ func recordFiltersAsPrometheusMetaLabel(filters []*filter.Filter) string {
 		}
 
 		builder.WriteString("config[|")
-		configKeys := lo.Keys(filter.Config)
+		configKeys := getMapKeys(filter.Config)
 		sort.Strings(configKeys)
 		for _, key := range configKeys {
 			fmt.Fprintf(&builder, "%s=%v|", key, filter.Config[key])
@@ -345,3 +344,15 @@ func (w *Worker) ServeHTTP(writer http.ResponseWriter, req *http.Request) {
 		w.logger.Error("Failed to write full HTTP response", "err", err, "bytes", bytesWritten)
 	}
 }
+
+func getMapKeys(m map[string]any) []string {
+	keys := make([]string, len(m))
+
+	i := 0
+	for key := range m {
+		keys[i] = key
+		i++
+	}
+
+	return keys
+}