From 25a008e2b11bbc63692553ba06ee27fd222224d4 Mon Sep 17 00:00:00 2001
From: Zachary Newman <z@znewman.net>
Date: Sat, 23 Apr 2022 18:16:20 -0400
Subject: [PATCH] feat: add "env://" scheme for blob load

Signed-off-by: Zachary Newman <z@znewman.net>
---
 pkg/blob/load.go      |  7 +++++++
 pkg/blob/load_test.go | 24 +++++++++++++++++++++++-
 2 files changed, 30 insertions(+), 1 deletion(-)

diff --git a/pkg/blob/load.go b/pkg/blob/load.go
index 2418f1c6f90..c92d49c4ca3 100644
--- a/pkg/blob/load.go
+++ b/pkg/blob/load.go
@@ -43,6 +43,13 @@ func LoadFileOrURL(fileRef string) ([]byte, error) {
 			if err != nil {
 				return nil, err
 			}
+		case "env://":
+			envVar := parts[1]
+			value, found := os.LookupEnv(envVar)
+			if !found {
+				return nil, fmt.Errorf("loading URL: env var $%s not found", envVar)
+			}
+			raw = []byte(value)
 		default:
 			return nil, fmt.Errorf("loading URL: unrecognized scheme: %s", scheme)
 		}
diff --git a/pkg/blob/load_test.go b/pkg/blob/load_test.go
index e94c5b552f0..c53b0621fd5 100644
--- a/pkg/blob/load_test.go
+++ b/pkg/blob/load_test.go
@@ -62,8 +62,30 @@ func TestLoadFileOrURL(t *testing.T) {
 		t.Errorf("LoadFileOrURL(HTTP) = '%s'; want '%s'", actual, data)
 	}
 
+	os.Setenv("MY_ENV_VAR", string(data))
+	actual, err = LoadFileOrURL("env://MY_ENV_VAR")
+	if err != nil {
+		t.Errorf("Reading from environment failed: %v", err)
+	} else if !bytes.Equal(actual, data) {
+		t.Errorf("LoadFileOrURL(env) = '%s'; want '%s'", actual, data)
+	}
+
+	os.Setenv("MY_ENV_VAR", "")
+	actual, err = LoadFileOrURL("env://MY_ENV_VAR")
+	if err != nil {
+		t.Errorf("Reading from environment failed: %v", err)
+	} else if !bytes.Equal(actual, make([]byte, 0)) {
+		t.Errorf("LoadFileOrURL(env) = '%s'; should be empty", actual)
+	}
+
+	os.Unsetenv("MY_ENV_VAR")
+	_, err = LoadFileOrURL("env://MY_ENV_VAR")
+	if err == nil {
+		t.Error("LoadFileOrURL(): expected error for unset env var")
+	}
+
 	_, err = LoadFileOrURL("invalid://url")
 	if err == nil {
-		t.Error("LoadFileOrURL(): expected error")
+		t.Error("LoadFileOrURL(): expected error for invalid scheme")
 	}
 }