From 736e5895ce481c6fd2f51e65173fb63c2d330781 Mon Sep 17 00:00:00 2001
From: Didier Roche <didier.roche@canonical.com>
Date: Wed, 4 Oct 2023 15:53:18 +0200
Subject: [PATCH] Allow env variable override, without associated flags

Visit manually env to bind every possibly related environment variable
to be able to unmarshall those into a struct.
More context on https://github.com/spf13/viper/pull/1429.
---
 cmd/authd/daemon/config.go | 15 +++++++++++++++
 1 file changed, 15 insertions(+)

diff --git a/cmd/authd/daemon/config.go b/cmd/authd/daemon/config.go
index 04cfcc9d1..92a2d4c02 100644
--- a/cmd/authd/daemon/config.go
+++ b/cmd/authd/daemon/config.go
@@ -6,6 +6,7 @@ import (
 	"fmt"
 	"os"
 	"path/filepath"
+	"strings"
 
 	"github.com/spf13/cobra"
 	"github.com/spf13/viper"
@@ -59,6 +60,20 @@ func initViperConfig(name string, cmd *cobra.Command, vip *viper.Viper) (err err
 	vip.SetEnvPrefix(name)
 	vip.AutomaticEnv()
 
+	// Visit manually env to bind every possibly related environment variable to be able to unmarshall
+	// those into a struct.
+	// More context on https://github.com/spf13/viper/pull/1429.
+	prefix := strings.ToUpper(name) + "_"
+	for _, e := range os.Environ() {
+		if !strings.HasPrefix(e, prefix) {
+			continue
+		}
+
+		s := strings.Split(e, "=")
+		k := strings.ReplaceAll(strings.TrimPrefix(s[0], prefix), "_", ".")
+		vip.BindEnv(k, s[0])
+	}
+
 	return nil
 }