Nagios2 command file updates with Go

cmdfile.go

package nagios2

/*********************************************************************
 * Nagios2 Command File access
 *
 * Copyright 2013 Bradley Dean
 *
 * 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/>.
 */

import (
        "os"
        "fmt"
        "time"
)

const (
        NAGIOS_CMD_FILE = "/var/lib/nagios2/rw/nagios.cmd"
)

type NagiosCmdFile struct {
        Fh *os.File
}

func GetNagiosCmdFile () (ncmd *NagiosCmdFile, err error) {
        fh, err := os.OpenFile(
                NAGIOS_CMD_FILE,
                os.O_RDWR,
                0660,
        )

        // Abort (with error) if file open fails
        if err != nil {
                return
        }

        ncmd = new(NagiosCmdFile)
        ncmd.Fh = fh

        return
}

func (ncmd *NagiosCmdFile) Close () error {
        return ncmd.Fh.Close()
}

func (ncmd *NagiosCmdFile) SendCommand (cmd string) error {
        // Check if this is a regular file
        fi, fi_err := ncmd.Fh.Stat()
        if fi_err != nil {
                return fi_err
        }
        is_regular_file := fi.Mode() & os.ModeType == 0

        // Seek to end (only if this is a regular file
        if is_regular_file {
                _, seek_err := ncmd.Fh.Seek(0, os.SEEK_END)
                if seek_err != nil {
                        return seek_err
                }
        }

        // TODO flock file, defer unlock
        // Consider: func Flock(fd int, how int) (err error)

        // Write command to file
        _, printf_err := fmt.Fprintf(ncmd.Fh, "[%d] %s\n", time.Now().Unix(), cmd)
        if printf_err != nil {
                return printf_err
        }

        // Sync to disk (only if this is a regular file)
        if is_regular_file {
                sync_err := ncmd.Fh.Sync()
                if sync_err != nil {
                        return sync_err
                }
        }

        // Success
        return nil
}

cmdfile_test.go

package nagios2

/*********************************************************************
 * Testing: Nagios2 Command File access
 *
 * Copyright 2013 Bradley Dean
 *
 * 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/>.
 */

import (
        "testing"
        "io"
        "fmt"
)

func TestGetNagiosCmdFile (t *testing.T) {
        var ncmd *NagiosCmdFile
        var err error
        ncmd, err = GetNagiosCmdFile()
        if err != nil {
                t.Error("Received error:", err)
        }
        if ncmd == ncmd {}
}

func TestCloseNagiosCmdFile (t *testing.T) {
        ncmd, err := GetNagiosCmdFile()
        if err == nil {
                defer ncmd.Close()
                var emptyif interface {}
                emptyif = ncmd
                if _, ok := emptyif.(io.Closer); ! ok {
                        t.Error("ncmd is not a Closer")
                }
        }
}

func TestSendCommand (t *testing.T) {
        ncmd, err := GetNagiosCmdFile()
        if err == nil {
                defer ncmd.Close()
                var err error
                err = ncmd.SendCommand("Test Command")
                if err != nil {
                        t.Error("Failed to send command:", err)
                }
        }
}

func BenchmarkGetNagiosCmdFile (b *testing.B) {
        ncmd, _ := GetNagiosCmdFile()
        defer ncmd.Close()
}

func ExampleGetNagiosCmdFile () {
        ncmd, err := GetNagiosCmdFile()
        fmt.Printf("%T\n", ncmd)
        fmt.Printf("%v\n", err)
        // Output:
        // *nagios2.NagiosCmdFile
        // <nil>
}