feature plugin custom flag (#251)

* support plugin custom flags

* add short name

* remove log

* remove log

tools/goctl/plugin/plugin_test.go

@@ -0,0 +1,29 @@
+package plugin
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func TestGetPluginAndArgs(t *testing.T) {
+	bin, args := getPluginAndArgs("android")
+	assert.Equal(t, "android", bin)
+	assert.Equal(t, "", args)
+
+	bin, args = getPluginAndArgs("android=")
+	assert.Equal(t, "android", bin)
+	assert.Equal(t, "", args)
+
+	bin, args = getPluginAndArgs("android=-javaPackage com.tal")
+	assert.Equal(t, "android", bin)
+	assert.Equal(t, "-javaPackage com.tal", args)
+
+	bin, args = getPluginAndArgs("android=-javaPackage com.tal --lambda")
+	assert.Equal(t, "android", bin)
+	assert.Equal(t, "-javaPackage com.tal --lambda", args)
+
+	bin, args = getPluginAndArgs(`https://test-xjy-file.obs.cn-east-2.myhuaweicloud.com/202012/8a7ab6e1-e639-49d1-89cf-2ae6127a1e90n=-v 1`)
+	assert.Equal(t, "https://test-xjy-file.obs.cn-east-2.myhuaweicloud.com/202012/8a7ab6e1-e639-49d1-89cf-2ae6127a1e90n", bin)
+	assert.Equal(t, "-v 1", args)
+}