feat(cfg): env secret/string support (#592)

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---------

Co-authored-by: Mark Lee <[email protected]>

pkg/cfg/env.go

@@ -0,0 +1,33 @@
+// Copyright 2024 Outreach Corporation. All Rights Reserved.
+
+// Description: Support for env loading env vars as strings or as SecretData
+
+package cfg
+
+import (
+	"os"
+
+	"github.com/pkg/errors"
+)
+
+// EnvSecret looks up a secret from the environment.
+func EnvSecret(name string) (SecretData, error) {
+	val, err := EnvString(name)
+	if err != nil {
+		return "", err
+	}
+	return SecretData(val), nil
+}
+
+// EnvString looks up a string from the environment.
+func EnvString(name string) (string, error) {
+	var (
+		ok  bool
+		val string
+	)
+	val, ok = os.LookupEnv(name)
+	if !ok {
+		return "", errors.Errorf("%q environment variable not set", name)
+	}
+	return val, nil
+}

pkg/cfg/env_test.go

@@ -0,0 +1,49 @@
+package cfg
+
+import (
+	"os"
+	"testing"
+
+	"github.com/google/uuid"
+	"gotest.tools/v3/assert"
+)
+
+func TestEnvString(t *testing.T) {
+	key := uuid.NewString()
+	value := uuid.NewString()
+	notsetKey := uuid.NewString()
+	err := os.Setenv(key, value)
+	assert.NilError(t, err, "failed to set environment variable")
+
+	t.Run("if key not set; error is returned", func(t *testing.T) {
+		_, err := EnvString(notsetKey)
+		assert.ErrorContains(t, err, notsetKey)
+		assert.ErrorContains(t, err, "environment variable not set")
+	})
+
+	t.Run("returns set value", func(t *testing.T) {
+		v, err := EnvString(key)
+		assert.NilError(t, err)
+
+		assert.Equal(t, v, value)
+	})
+}
+
+func TestEnvSecret(t *testing.T) {
+	key := uuid.NewString()
+	value := uuid.NewString()
+	notsetKey := uuid.NewString()
+	err := os.Setenv(key, value)
+	assert.NilError(t, err, "failed to set environment variable")
+
+	t.Run("if key not set; error is returned", func(t *testing.T) {
+		_, err := EnvSecret(notsetKey)
+		assert.ErrorContains(t, err, notsetKey)
+		assert.ErrorContains(t, err, "environment variable not set")
+	})
+
+	v, err := EnvSecret(key)
+	assert.NilError(t, err)
+
+	assert.Equal(t, string(v), value)
+}