Files
mgmt/gapi/empty/empty.go
James Shubin 88516546fa lib: Move to go modules and shed a few tears
The old system with vendor/ and git submodules worked great,
unfortunately FUD around git submodules seemed to scare people away and
golang moved to a go.mod system that adds a new lock file format instead
of using the built-in git version. It's now almost impossible to use
modern golang without this, so we've switched.

So much for the golang compatibility promise-- turns out it doesn't
apply to the useful parts that I actually care about like this.

Thanks to frebib for his incredibly valuable contributions to this
patch. This snide commit message is mine alone.

This patch also mixes in some changes due to legacy golang as we've also
bumped the minimum version to 1.16 in the docs and tests.

Lastly, we had to disable some tests and fix up a few other misc things
to get this passing. We've definitely hot bugs in the go.mod system, and
our Makefile tries to workaround those.
2021-10-05 08:34:51 -04:00

137 lines
3.4 KiB
Go

// Mgmt
// Copyright (C) 2013-2021+ 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 empty
import (
"fmt"
"sync"
"github.com/purpleidea/mgmt/gapi"
"github.com/purpleidea/mgmt/pgraph"
"github.com/urfave/cli/v2"
)
const (
// Name is the name of this frontend.
Name = "empty"
)
func init() {
gapi.Register(Name, func() gapi.GAPI { return &GAPI{} }) // register
}
// GAPI implements the main lang GAPI interface.
type GAPI struct {
data *gapi.Data
initialized bool
closeChan chan struct{}
wg *sync.WaitGroup // sync group for tunnel go routines
}
// CliFlags returns a list of flags used by the specified subcommand.
func (obj *GAPI) CliFlags(command string) []cli.Flag {
return []cli.Flag{}
}
// Cli takes a cli.Context, and returns our GAPI if activated. All arguments
// should take the prefix of the registered name. On activation, if there are
// any validation problems, you should return an error. If this was not
// activated, then you should return a nil GAPI and a nil error.
func (obj *GAPI) Cli(*gapi.CliInfo) (*gapi.Deploy, error) {
return &gapi.Deploy{
Name: Name,
//Noop: false,
GAPI: &GAPI{},
}, nil
}
// Init initializes the lang GAPI struct.
func (obj *GAPI) Init(data *gapi.Data) error {
if obj.initialized {
return fmt.Errorf("already initialized")
}
obj.data = data // store for later
obj.closeChan = make(chan struct{})
obj.wg = &sync.WaitGroup{}
obj.initialized = true
return nil
}
// Graph returns a current Graph.
func (obj *GAPI) Graph() (*pgraph.Graph, error) {
if !obj.initialized {
return nil, fmt.Errorf("%s: GAPI is not initialized", Name)
}
obj.data.Logf("generating empty graph...")
g, err := pgraph.NewGraph("empty")
if err != nil {
return nil, err
}
return g, nil
}
// Next returns nil errors every time there could be a new graph.
func (obj *GAPI) Next() chan gapi.Next {
ch := make(chan gapi.Next)
obj.wg.Add(1)
go func() {
defer obj.wg.Done()
defer close(ch) // this will run before the obj.wg.Done()
if !obj.initialized {
next := gapi.Next{
Err: fmt.Errorf("%s: GAPI is not initialized", Name),
Exit: true, // exit, b/c programming error?
}
select {
case ch <- next:
case <-obj.closeChan:
}
return
}
// send only one event
next := gapi.Next{
Exit: false,
Err: nil,
}
select {
case ch <- next: // trigger a run (send a msg)
// pass
// unblock if we exit while waiting to send!
case <-obj.closeChan:
return
}
}()
return ch
}
// Close shuts down the lang GAPI.
func (obj *GAPI) Close() error {
if !obj.initialized {
return fmt.Errorf("%s: GAPI is not initialized", Name)
}
close(obj.closeChan)
obj.wg.Wait()
obj.initialized = false // closed = true
return nil
}