Files
mgmt/exec.go
James Shubin 3a85384377 Rename type to resource (res) and service to svc
Naming the resources "type" was a stupid mistake, and is a huge source
of confusion when also talking about real types. Fix this before it gets
out of hand.
2016-02-21 15:51:52 -05:00

340 lines
9.7 KiB
Go

// Mgmt
// Copyright (C) 2013-2016+ 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 Affero 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 Affero General Public License for more details.
//
// You should have received a copy of the GNU Affero General Public License
// along with this program. If not, see <http://www.gnu.org/licenses/>.
package main
import (
"bufio"
"bytes"
"log"
"os/exec"
"strings"
)
type ExecRes struct {
BaseRes `yaml:",inline"`
State string `yaml:"state"` // state: exists/present?, absent, (undefined?)
Cmd string `yaml:"cmd"` // the command to run
Shell string `yaml:"shell"` // the (optional) shell to use to run the cmd
Timeout int `yaml:"timeout"` // the cmd timeout in seconds
WatchCmd string `yaml:"watchcmd"` // the watch command to run
WatchShell string `yaml:"watchshell"` // the (optional) shell to use to run the watch cmd
IfCmd string `yaml:"ifcmd"` // the if command to run
IfShell string `yaml:"ifshell"` // the (optional) shell to use to run the if cmd
PollInt int `yaml:"pollint"` // the poll interval for the ifcmd
}
func NewExecRes(name, cmd, shell string, timeout int, watchcmd, watchshell, ifcmd, ifshell string, pollint int, state string) *ExecRes {
// FIXME if path = nil, path = name ...
return &ExecRes{
BaseRes: BaseRes{
Name: name,
events: make(chan Event),
vertex: nil,
},
Cmd: cmd,
Shell: shell,
Timeout: timeout,
WatchCmd: watchcmd,
WatchShell: watchshell,
IfCmd: ifcmd,
IfShell: ifshell,
PollInt: pollint,
State: state,
}
}
func (obj *ExecRes) GetRes() string {
return "Exec"
}
// validate if the params passed in are valid data
// FIXME: where should this get called ?
func (obj *ExecRes) Validate() bool {
if obj.Cmd == "" { // this is the only thing that is really required
return false
}
// if we have a watch command, then we don't poll with the if command!
if obj.WatchCmd != "" && obj.PollInt > 0 {
return false
}
return true
}
// wraps the scanner output in a channel
func (obj *ExecRes) BufioChanScanner(scanner *bufio.Scanner) (chan string, chan error) {
ch, errch := make(chan string), make(chan error)
go func() {
for scanner.Scan() {
ch <- scanner.Text() // blocks here ?
if e := scanner.Err(); e != nil {
errch <- e // send any misc errors we encounter
//break // TODO ?
}
}
close(ch)
errch <- scanner.Err() // eof or some err
close(errch)
}()
return ch, errch
}
// Exec watcher
func (obj *ExecRes) Watch() {
if obj.IsWatching() {
return
}
obj.SetWatching(true)
defer obj.SetWatching(false)
var send = false // send event?
var exit = false
bufioch, errch := make(chan string), make(chan error)
//vertex := obj.GetVertex() // stored with SetVertex
if obj.WatchCmd != "" {
var cmdName string
var cmdArgs []string
if obj.WatchShell == "" {
// call without a shell
// FIXME: are there still whitespace splitting issues?
split := strings.Fields(obj.WatchCmd)
cmdName = split[0]
//d, _ := os.Getwd() // TODO: how does this ever error ?
//cmdName = path.Join(d, cmdName)
cmdArgs = split[1:len(split)]
} else {
cmdName = obj.Shell // usually bash, or sh
cmdArgs = []string{"-c", obj.WatchCmd}
}
cmd := exec.Command(cmdName, cmdArgs...)
//cmd.Dir = "" // look for program in pwd ?
cmdReader, err := cmd.StdoutPipe()
if err != nil {
log.Printf("%v[%v]: Error creating StdoutPipe for Cmd: %v", obj.GetRes(), obj.GetName(), err)
log.Fatal(err) // XXX: how should we handle errors?
}
scanner := bufio.NewScanner(cmdReader)
defer cmd.Wait() // XXX: is this necessary?
defer func() {
// FIXME: without wrapping this in this func it panic's
// when running examples/graph8d.yaml
cmd.Process.Kill() // TODO: is this necessary?
}()
if err := cmd.Start(); err != nil {
log.Printf("%v[%v]: Error starting Cmd: %v", obj.GetRes(), obj.GetName(), err)
log.Fatal(err) // XXX: how should we handle errors?
}
bufioch, errch = obj.BufioChanScanner(scanner)
}
for {
obj.SetState(resStateWatching) // reset
select {
case text := <-bufioch:
obj.SetConvergedState(resConvergedNil)
// each time we get a line of output, we loop!
log.Printf("%v[%v]: Watch output: %s", obj.GetRes(), obj.GetName(), text)
if text != "" {
send = true
}
case err := <-errch:
obj.SetConvergedState(resConvergedNil) // XXX ?
if err == nil { // EOF
// FIXME: add an "if watch command ends/crashes"
// restart or generate error option
log.Printf("%v[%v]: Reached EOF", obj.GetRes(), obj.GetName())
return
}
log.Printf("%v[%v]: Error reading input?: %v", obj.GetRes(), obj.GetName(), err)
log.Fatal(err)
// XXX: how should we handle errors?
case event := <-obj.events:
obj.SetConvergedState(resConvergedNil)
if exit, send = obj.ReadEvent(&event); exit {
return // exit
}
case _ = <-TimeAfterOrBlock(obj.ctimeout):
obj.SetConvergedState(resConvergedTimeout)
obj.converged <- true
continue
}
// do all our event sending all together to avoid duplicate msgs
if send {
send = false
// it is okay to invalidate the clean state on poke too
obj.isStateOK = false // something made state dirty
Process(obj) // XXX: rename this function
}
}
}
// TODO: expand the IfCmd to be a list of commands
func (obj *ExecRes) StateOK() bool {
// if there is a watch command, but no if command, run based on state
if b := obj.isStateOK; obj.WatchCmd != "" && obj.IfCmd == "" {
obj.isStateOK = true // reset
//if !obj.isStateOK { obj.isStateOK = true; return false }
return b
// if there is no watcher, but there is an onlyif check, run it to see
} else if obj.IfCmd != "" { // && obj.WatchCmd == ""
// there is a watcher, but there is also an if command
//} else if obj.IfCmd != "" && obj.WatchCmd != "" {
if obj.PollInt > 0 { // && obj.WatchCmd == ""
// XXX have the Watch() command output onlyif poll events...
// XXX we can optimize by saving those results for returning here
// return XXX
}
var cmdName string
var cmdArgs []string
if obj.IfShell == "" {
// call without a shell
// FIXME: are there still whitespace splitting issues?
split := strings.Fields(obj.IfCmd)
cmdName = split[0]
//d, _ := os.Getwd() // TODO: how does this ever error ?
//cmdName = path.Join(d, cmdName)
cmdArgs = split[1:len(split)]
} else {
cmdName = obj.IfShell // usually bash, or sh
cmdArgs = []string{"-c", obj.IfCmd}
}
err := exec.Command(cmdName, cmdArgs...).Run()
if err != nil {
// TODO: check exit value
return true // don't run
}
return false // just run
// if there is no watcher and no onlyif check, assume we should run
} else { // if obj.WatchCmd == "" && obj.IfCmd == "" {
b := obj.isStateOK
obj.isStateOK = true
return b // just run if state is dirty
}
}
func (obj *ExecRes) Apply() bool {
log.Printf("%v[%v]: Apply", obj.GetRes(), obj.GetName())
var cmdName string
var cmdArgs []string
if obj.Shell == "" {
// call without a shell
// FIXME: are there still whitespace splitting issues?
// TODO: we could make the split character user selectable...!
split := strings.Fields(obj.Cmd)
cmdName = split[0]
//d, _ := os.Getwd() // TODO: how does this ever error ?
//cmdName = path.Join(d, cmdName)
cmdArgs = split[1:len(split)]
} else {
cmdName = obj.Shell // usually bash, or sh
cmdArgs = []string{"-c", obj.Cmd}
}
cmd := exec.Command(cmdName, cmdArgs...)
//cmd.Dir = "" // look for program in pwd ?
var out bytes.Buffer
cmd.Stdout = &out
if err := cmd.Start(); err != nil {
log.Printf("%v[%v]: Error starting Cmd: %v", obj.GetRes(), obj.GetName(), err)
return false
}
timeout := obj.Timeout
if timeout == 0 { // zero timeout means no timer, so disable it
timeout = -1
}
done := make(chan error)
go func() { done <- cmd.Wait() }()
select {
case err := <-done:
if err != nil {
log.Printf("%v[%v]: Error waiting for Cmd: %v", obj.GetRes(), obj.GetName(), err)
return false
}
case <-TimeAfterOrBlock(timeout):
log.Printf("%v[%v]: Timeout waiting for Cmd", obj.GetRes(), obj.GetName())
//cmd.Process.Kill() // TODO: is this necessary?
return false
}
// TODO: if we printed the stdout while the command is running, this
// would be nice, but it would require terminal log output that doesn't
// interleave all the parallel parts which would mix it all up...
if s := out.String(); s == "" {
log.Printf("Exec[%v]: Command output is empty!", obj.Name)
} else {
log.Printf("Exec[%v]: Command output is:", obj.Name)
log.Printf(out.String())
}
// XXX: return based on exit value!!
return true
}
func (obj *ExecRes) Compare(res Res) bool {
switch res.(type) {
case *ExecRes:
res := res.(*ExecRes)
if obj.Name != res.Name {
return false
}
if obj.Cmd != res.Cmd {
return false
}
if obj.Shell != res.Shell {
return false
}
if obj.Timeout != res.Timeout {
return false
}
if obj.WatchCmd != res.WatchCmd {
return false
}
if obj.WatchShell != res.WatchShell {
return false
}
if obj.IfCmd != res.IfCmd {
return false
}
if obj.PollInt != res.PollInt {
return false
}
if obj.State != res.State {
return false
}
default:
return false
}
return true
}