lang: funcs: Added an uptime function

Signed-off-by: Toshaan Bharvani <toshaan@vantosh.com>

examples/lang/uptime0.mcl

@@ -0,0 +1,8 @@
+import "fmt"
+import "sys"
+
+$uptime = sys.uptime()
+
+print "print1" {
+	msg => fmt.printf("uptime: %d", $uptime),
+}

lang/funcs/core/sys/uptime_fact.go

@@ -0,0 +1,89 @@
+// Mgmt
+// Copyright (C) 2013-2018+ 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 coresys
+
+import (
+	"time"
+
+	"github.com/purpleidea/mgmt/lang/funcs/facts"
+	"github.com/purpleidea/mgmt/lang/types"
+
+	errwrap "github.com/pkg/errors"
+)
+
+func init() {
+	facts.ModuleRegister(moduleName, "uptime", func() facts.Fact { return &UptimeFact{} })
+}
+
+// UptimeFact is a fact which returns the current uptime of your system.
+type UptimeFact struct {
+	init      *facts.Init
+	closeChan chan struct{}
+}
+
+// Info returns some static info about itself.
+func (obj *UptimeFact) Info() *facts.Info {
+	return &facts.Info{
+		Output: types.TypeInt,
+	}
+}
+
+// Init runs some startup code for this fact.
+func (obj *UptimeFact) Init(init *facts.Init) error {
+	obj.init = init
+	obj.closeChan = make(chan struct{})
+	return nil
+}
+
+// Stream returns the changing values that this fact has over time.
+func (obj *UptimeFact) Stream() error {
+	defer close(obj.init.Output)
+	ticker := time.NewTicker(time.Duration(1) * time.Second)
+
+	startChan := make(chan struct{})
+	close(startChan)
+	defer ticker.Stop()
+	for {
+		select {
+		case <-startChan:
+			startChan = nil
+		case <-ticker.C:
+			// send
+		case <-obj.closeChan:
+			return nil
+		}
+
+		uptime, err := uptime()
+		if err != nil {
+			return errwrap.Wrapf(err, "could not read uptime value")
+		}
+
+		select {
+		case obj.init.Output <- &types.IntValue{V: uptime}:
+			// send
+		case <-obj.closeChan:
+			return nil
+		}
+	}
+}
+
+// Close runs some shutdown code for this fact and turns off the stream.
+func (obj *UptimeFact) Close() error {
+	close(obj.closeChan)
+	return nil
+}

lang/funcs/core/sys/uptime_fact_posix.go

@@ -0,0 +1,32 @@
+// Mgmt
+// Copyright (C) 2013-2018+ 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/>.
+
+// +build !darwin
+
+package coresys
+
+import (
+	"syscall"
+)
+
+func uptime() (int64, error) {
+	var sysinfo syscall.Sysinfo_t
+	if err := syscall.Sysinfo(&sysinfo); err != nil {
+		return 0, err
+	}
+	return sysinfo.Uptime, nil
+}