Add Step environment variables

pkg/plugin/env.go

@@ -0,0 +1,20 @@
+// Copyright (c) 2019, the Drone Plugins project authors.
+// Please see the AUTHORS file for details. All rights reserved.
+// Use of this source code is governed by an Apache 2.0 license that can be
+// found in the LICENSE file.
+
+package plugin
+
+// List of enviornment variables set by Drone when running a step within a
+// build stage.
+//
+// Multiple values are specified with `,` within the string. If there are
+// multiple values this is to support backward compatibility with versions of
+// Drone prior to the 1.0 release.
+
+const (
+	// StepNameEnvVar is the environment variable for setting Step.Name.
+	StepNameEnvVar = "DRONE_STEP_NAME"
+	// StepNumberEnvVar is the environment variable for setting Step.Number.
+	StepNumberEnvVar = "DRONE_STEP_NUMBER"
+)