Add urfave parsing of Step

go.mod

@@ -0,0 +1,5 @@
+module github.com/drone-plugins/drone-plugin-lib
+
+go 1.13
+
+require github.com/urfave/cli v1.21.0

go.sum

@@ -0,0 +1,5 @@
+github.com/BurntSushi/toml v0.3.1/go.mod h1:xHWCNGjB5oqiDr8zfno3MHue2Ht5sIBksp03qcyfWMU=
+github.com/urfave/cli v1.21.0 h1:wYSSj06510qPIzGSua9ZqsncMmWE3Zr55KBERygyrxE=
+github.com/urfave/cli v1.21.0/go.mod h1:lxDj6qX9Q6lWQxIrbrT0nwecwUtRnhVZAJjJZrVUZZQ=
+gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
+gopkg.in/yaml.v2 v2.2.2/go.mod h1:hI93XBmqTisBFMUTm0b8Fm+jr3Dg1NNxqwp+5A1VGuI=

pkg/urfave/urfave.go

@@ -0,0 +1,72 @@
+// 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 urfave provides helpers for interacting with the `urfave/cli`
+// package when creating plugins for use by the Drone CI/CD service.
+//
+// Drone communicates to plugins by passing in environment variables that have
+// information on the currently executing build. The `urfave/cli` package can
+// read these environment variables and extract them into structs.
+//
+//     import(
+//         "github.com/drone-plugins/drone-plugin-lib/pkg/urfave"
+//         "github.com/urfave/cli"
+//	   )
+//
+//     func main() {
+//         app := cli.New()
+//         app.Name = "my awesome Drone plugin"
+//         app.Run = run
+//         app.Flags = []cli.Flags{
+//             // All my plugin flags
+//         }
+//         app.Flags = append(
+//             app.Flags,
+//             urfave.CommitFlags()...,
+//         )
+//     }
+package urfave
+
+import (
+	"github.com/drone-plugins/drone-plugin-lib/pkg/plugin"
+	"github.com/urfave/cli"
+)
+
+//---------------------------------------------------------------------
+// Step Flags
+//---------------------------------------------------------------------
+
+const (
+	// StepNameFlag is the flag name for setting plugin.Step.Name.
+	StepNameFlag = "step.name"
+	// StepNumberFlag is the flag name for setting plugin.Step.Number.
+	StepNumberFlag = "step.number"
+)
+
+// StepFlags has the cli.Flags for the plugin.Step.
+func StepFlags() []cli.Flag {
+	return []cli.Flag{
+		cli.StringFlag{
+			Name:   StepNameFlag,
+			Usage:  "step name",
+			EnvVar: plugin.StepNameEnvVar,
+			Hidden: true,
+		},
+		cli.StringFlag{
+			Name:   StepNumberFlag,
+			Usage:  "step number",
+			EnvVar: plugin.StepNumberEnvVar,
+			Hidden: true,
+		},
+	}
+}
+
+// StepFromContext creates a plugin.Step from the cli.Context.
+func StepFromContext(ctx cli.Context) plugin.Step {
+	return plugin.Step{
+		Name:   ctx.String(StepNameFlag),
+		Number: ctx.Int(StepNumberFlag),
+	}
+}