From a3f44cf1239bc3c771134a7ad6021831fde1ef23 Mon Sep 17 00:00:00 2001
From: Philippe Caseiro <pcaseiro@cadoles.com>
Date: Mon, 10 Jul 2023 16:59:00 +0200
Subject: [PATCH] fix(config): supporting multiple env variables in a value.

ref #9
---
 go.mod                              |  1 +
 go.sum                              |  2 ++
 internal/config/environment.go      | 16 +++++++++++++---
 internal/config/testdata/config.yml |  4 ++--
 4 files changed, 18 insertions(+), 5 deletions(-)

diff --git a/go.mod b/go.mod
index 1446537..baed41a 100644
--- a/go.mod
+++ b/go.mod
@@ -6,6 +6,7 @@ require (
 	forge.cadoles.com/Cadoles/go-proxy v0.0.0-20230701194111-c6b3d482cca6
 	github.com/Masterminds/sprig/v3 v3.2.3
 	github.com/btcsuite/btcd/btcutil v1.1.3
+	github.com/drone/envsubst v1.0.3
 	github.com/getsentry/sentry-go v0.22.0
 	github.com/go-chi/chi/v5 v5.0.8
 	github.com/jedib0t/go-pretty/v6 v6.4.6
diff --git a/go.sum b/go.sum
index 2d32448..942e850 100644
--- a/go.sum
+++ b/go.sum
@@ -163,6 +163,8 @@ github.com/docker/go-connections v0.4.0 h1:El9xVISelRB7BuFusrZozjnkIM5YnzCViNKoh
 github.com/docker/go-connections v0.4.0/go.mod h1:Gbd7IOopHjR8Iph03tsViu4nIes5XhDvyHbTtUxmeec=
 github.com/docker/go-units v0.4.0 h1:3uh0PgVws3nIA0Q+MwDC8yjEPf9zjRfZZWXZYDct3Tw=
 github.com/docker/go-units v0.4.0/go.mod h1:fgPhTUdO+D/Jk86RDLlptpiXQzgHJF7gydDDbaIK4Dk=
+github.com/drone/envsubst v1.0.3 h1:PCIBwNDYjs50AsLZPYdfhSATKaRg/FJmDc2D6+C2x8g=
+github.com/drone/envsubst v1.0.3/go.mod h1:N2jZmlMufstn1KEqvbHjw40h1KyTmnVzHcSc9bFiJ2g=
 github.com/envoyproxy/go-control-plane v0.9.0/go.mod h1:YTl/9mNaCwkRvm6d1a2C3ymFceY/DCBVvsKhRF0iEA4=
 github.com/envoyproxy/go-control-plane v0.9.1-0.20191026205805-5f8ba28d4473/go.mod h1:YTl/9mNaCwkRvm6d1a2C3ymFceY/DCBVvsKhRF0iEA4=
 github.com/envoyproxy/go-control-plane v0.9.4/go.mod h1:6rpuAdCZL397s3pYoYcLgu1mIlRU8Am5FuJP05cCM98=
diff --git a/internal/config/environment.go b/internal/config/environment.go
index 201f9a8..be9bc56 100644
--- a/internal/config/environment.go
+++ b/internal/config/environment.go
@@ -6,11 +6,13 @@ import (
 	"strconv"
 	"time"
 
+	"github.com/drone/envsubst"
 	"github.com/pkg/errors"
 	"gopkg.in/yaml.v3"
 )
 
-var reVar = regexp.MustCompile(`^\${(\w+)}$`)
+// var reVar = regexp.MustCompile(`^\${(\w+)}$`)
+var reVar = regexp.MustCompile(`\${(.*?)}`)
 
 type InterpolatedString string
 
@@ -130,14 +132,22 @@ type InterpolatedStringSlice []string
 
 func (iss *InterpolatedStringSlice) UnmarshalYAML(value *yaml.Node) error {
 	var data []string
+	var evErr error
 
 	if err := value.Decode(&data); err != nil {
 		return errors.Wrapf(err, "could not decode value '%v' (line '%d') into map", value.Value, value.Line)
 	}
 
 	for index, value := range data {
-		if match := reVar.FindStringSubmatch(value); len(match) > 0 {
-			value = os.Getenv(match[1])
+		//match := reVar.FindStringSubmatch(value)
+		re := regexp.MustCompile(`\${(.*?)}`)
+
+		res := re.FindAllStringSubmatch(value, 10)
+		if len(res) > 0 {
+			value, evErr = envsubst.EvalEnv(value)
+			if evErr != nil {
+				return evErr
+			}
 		}
 
 		data[index] = value
diff --git a/internal/config/testdata/config.yml b/internal/config/testdata/config.yml
index e06a61b..030a087 100644
--- a/internal/config/testdata/config.yml
+++ b/internal/config/testdata/config.yml
@@ -2,5 +2,5 @@ logger:
   level: 0
   format: human
 http:
-  host: "0.0.0.0"
-  port: 3000
\ No newline at end of file
+  host: "${LISTEN_ADDR}"
+  port: 3000