From d57039357e8734c5a7f3859b51f8c953cd8bd54a Mon Sep 17 00:00:00 2001
From: Andrew Suderman <andrew@sudermanjr.com>
Date: Fri, 1 Apr 2022 13:01:51 -0600
Subject: [PATCH] Allow escaping $ in environment variable interpolation (#560)

* Add test for escaped dollar signs

* Check for 2663 and return it rather than an error in env parsing

* Consolidate the parEnv and envMapper functions
---
 .../course_files/03_test_env_var.yml          |  6 ++
 pkg/course/course.go                          | 19 ++++---
 pkg/course/course_test.go                     | 56 +++++++++++++++++++
 3 files changed, 72 insertions(+), 9 deletions(-)

diff --git a/end_to_end_testing/course_files/03_test_env_var.yml b/end_to_end_testing/course_files/03_test_env_var.yml
index 3ca6ae1a..4432d4f3 100644
--- a/end_to_end_testing/course_files/03_test_env_var.yml
+++ b/end_to_end_testing/course_files/03_test_env_var.yml
@@ -15,3 +15,9 @@ charts:
       comment-problem-detector:
         # This is a comment "${this_var_should_not_be_parsed}"
         - test-value
+  escape-values:
+    repository: fairwinds-incubator
+    chart: basic-demo
+    namespace: 03-infra
+    values:
+      non-used: "A string that needs a $$ in it"
diff --git a/pkg/course/course.go b/pkg/course/course.go
index f37eba56..f2054fca 100644
--- a/pkg/course/course.go
+++ b/pkg/course/course.go
@@ -625,21 +625,22 @@ func parseSecrets(courseData []byte) error {
 }
 
 func parseEnv(data string) (string, error) {
-	dataWithEnv := os.Expand(data, envMapper)
+	dataWithEnv := os.Expand(data, func(key string) string {
+		if key == "$" {
+			return "$$"
+		}
+		if value, ok := os.LookupEnv(key); ok {
+			return value
+		}
+		color.Red("ERROR: environment variable %s is not set", key)
+		return "_ENV_NOT_SET_"
+	})
 	if strings.Contains(dataWithEnv, "_ENV_NOT_SET_") {
 		return data, fmt.Errorf("course has env variables that are not properly set")
 	}
 	return dataWithEnv, nil
 }
 
-func envMapper(key string) string {
-	if value, ok := os.LookupEnv(key); ok {
-		return value
-	}
-	color.Red("ERROR: environment variable %s is not set", key)
-	return "_ENV_NOT_SET_"
-}
-
 func boolPtr(b bool) *bool {
 	return &b
 }
diff --git a/pkg/course/course_test.go b/pkg/course/course_test.go
index aa2f1130..57cfe84c 100644
--- a/pkg/course/course_test.go
+++ b/pkg/course/course_test.go
@@ -15,6 +15,7 @@
 package course
 
 import (
+	"os"
 	"testing"
 
 	"github.com/stretchr/testify/assert"
@@ -221,3 +222,58 @@ func TestFileV2_populateDefaultRepository(t *testing.T) {
 		})
 	}
 }
+
+func Test_parseEnv(t *testing.T) {
+
+	tests := []struct {
+		name    string
+		data    string
+		want    string
+		envMap  map[string]string
+		wantErr bool
+	}{
+		{
+			name:    "basic error check",
+			data:    "$this-is-certainly-not-a-valid-env-var",
+			wantErr: true,
+		},
+		{
+			name: "basic test",
+			data: "$TEST_ENV_KEY",
+			want: "test-env-value",
+			envMap: map[string]string{
+				"TEST_ENV_KEY": "test-env-value",
+			},
+			wantErr: false,
+		},
+		{
+			name: "escaping test",
+			data: "$$TEST_ENV_KEY",
+			want: "$$TEST_ENV_KEY",
+			envMap: map[string]string{
+				"TEST_ENV_KEY": "test-env-value",
+			},
+			wantErr: false,
+		},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			for k, v := range tt.envMap {
+				os.Setenv(k, v)
+			}
+
+			got, err := parseEnv(tt.data)
+			if tt.wantErr {
+				assert.Error(t, err)
+			} else {
+				assert.NoError(t, err)
+				assert.EqualValues(t, tt.want, got)
+			}
+		})
+	}
+}
+
+func Test_boolPtr(t *testing.T) {
+	testBool := true
+	assert.EqualValues(t, &testBool, boolPtr(testBool))
+}