engine, gapi, lang, lib: Plumb through new local API

This is a new API that is similar in spirit and plumbing to the World
API, but it intended for all local machine operations and will likely
only ever have one implementation.

engine/graph/engine.go

@@ -28,6 +28,7 @@ import (
 
 	"github.com/purpleidea/mgmt/converger"
 	"github.com/purpleidea/mgmt/engine"
+	"github.com/purpleidea/mgmt/engine/local"
 	engineUtil "github.com/purpleidea/mgmt/engine/util"
 	"github.com/purpleidea/mgmt/pgraph"
 	"github.com/purpleidea/mgmt/util/errwrap"
@@ -47,6 +48,7 @@ type Engine struct {
 	Hostname string
 
 	Converger *converger.Coordinator
+	Local     *local.API
 	World     engine.World
 
 	// Prefix is a unique directory prefix which can be used. It should be
@@ -224,6 +226,7 @@ func (obj *Engine) Commit() error {
 			Hostname: obj.Hostname,
 
 			//Converger: obj.Converger,
+			Local:  obj.Local,
 			World:  obj.World,
 			Prefix: statePrefix,
 

engine/graph/state.go

@@ -25,6 +25,7 @@ import (
 
 	"github.com/purpleidea/mgmt/converger"
 	"github.com/purpleidea/mgmt/engine"
+	"github.com/purpleidea/mgmt/engine/local"
 	engineUtil "github.com/purpleidea/mgmt/engine/util"
 	"github.com/purpleidea/mgmt/pgraph"
 	"github.com/purpleidea/mgmt/util/errwrap"
@@ -46,6 +47,7 @@ type State struct {
 
 	//Converger *converger.Coordinator
 
+	Local *local.API
 	World engine.World
 
 	// Prefix is a unique directory prefix which can be used. It should be
@@ -239,6 +241,7 @@ func (obj *State) Init() error {
 			return graph, nil // we return in a func so it's fresh!
 		},
 
+		Local:  obj.Local,
 		World:  obj.World,
 		VarDir: obj.varDir,
 

engine/local/local.go

@@ -0,0 +1,36 @@
+// Mgmt
+// Copyright (C) 2013-2023+ James Shubin and the project contributors
+// Written by James Shubin <james@shubin.ca> and the project contributors
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+// Package local contains functions and interfaces that are shared between
+// functions and resources. It's similar to the "world" functionality, except
+// that it only involves local operations that stay within a single machine or
+// local mgmt instance.
+package local
+
+import (
+	"context"
+)
+
+// API implements the base handle for all the methods in this package. If we
+// were going to have more than one implementation for all of these, then this
+// would be an interface instead, and different packages would implement it.
+// Since this is not the expectation for the local API, it's all self-contained.
+type API struct {
+	Prefix string
+	Debug  bool
+	Logf   func(format string, v ...interface{})
+}

engine/resources.go

@@ -22,6 +22,7 @@ import (
 	"encoding/gob"
 	"fmt"
 
+	"github.com/purpleidea/mgmt/engine/local"
 	"github.com/purpleidea/mgmt/pgraph"
 	"github.com/purpleidea/mgmt/util/errwrap"
 
@@ -135,6 +136,11 @@ type Init struct {
 
 	// TODO: GraphQuery offers an interface to query the resource graph.
 
+	// Local has a bunch of methods and properties which are useful for
+	// operations on the local machine and for communication between
+	// functions and resources.
+	Local *local.API
+
 	// World provides a connection to the outside world. This is most often
 	// used for communicating with the distributed database.
 	World World