Files
mgmt/lang/core/example/flipflop_fact.go
James Shubin d6cf595899 lang: Unnested the core package from the functions dir
The core package could contain non-functions, so we might as well move
it upwards.
2024-02-22 17:19:02 -05:00

102 lines
3.0 KiB
Go

// Mgmt
// Copyright (C) 2013-2024+ 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 coreexample
import (
"context"
"time"
"github.com/purpleidea/mgmt/lang/funcs/facts"
"github.com/purpleidea/mgmt/lang/types"
)
const (
// FlipFlopFuncName is the name this fact is registered as. It's still a
// Func Name because this is the name space the fact is actually using.
FlipFlopFuncName = "flipflop"
)
func init() {
facts.ModuleRegister(ModuleName, FlipFlopFuncName, func() facts.Fact { return &FlipFlopFact{} }) // must register the fact and name
}
// FlipFlopFact is a fact which flips a bool repeatedly. This is an example fact
// and is not meant for serious computing. This would be better served by a flip
// function which you could specify an interval for.
type FlipFlopFact struct {
init *facts.Init
value bool
}
// String returns a simple name for this fact. This is needed so this struct can
// satisfy the pgraph.Vertex interface.
func (obj *FlipFlopFact) String() string {
return FlipFlopFuncName
}
// Validate makes sure we've built our struct properly. It is usually unused for
// normal facts that users can use directly.
//func (obj *FlipFlopFact) Validate() error {
// return nil
//}
// Info returns some static info about itself.
func (obj *FlipFlopFact) Info() *facts.Info {
return &facts.Info{
Output: types.NewType("bool"),
}
}
// Init runs some startup code for this fact.
func (obj *FlipFlopFact) Init(init *facts.Init) error {
obj.init = init
return nil
}
// Stream returns the changing values that this fact has over time.
func (obj *FlipFlopFact) Stream(ctx context.Context) error {
defer close(obj.init.Output) // always signal when we're done
// TODO: don't hard code 5 sec interval
ticker := time.NewTicker(time.Duration(5) * time.Second)
// streams must generate an initial event on startup
startChan := make(chan struct{}) // start signal
close(startChan) // kick it off!
defer ticker.Stop()
for {
select {
case <-startChan: // kick the loop once at start
startChan = nil // disable
case <-ticker.C: // received the timer event
// pass
case <-ctx.Done():
return nil
}
select {
case obj.init.Output <- &types.BoolValue{ // flip
V: obj.value,
}:
case <-ctx.Done():
return nil
}
obj.value = !obj.value // flip it
}
}