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Move lock command to its own package

This commit is contained in:
Preetha Appan 2017-10-12 16:02:45 -05:00 committed by Frank Schröder
parent 85bc32f8a0
commit ff4d070bdf
5 changed files with 99 additions and 82 deletions
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9
command/commands.go
View File

@ -23,6 +23,7 @@ import (
"github.com/hashicorp/consul/command/kvimp"
"github.com/hashicorp/consul/command/kvput"
"github.com/hashicorp/consul/command/leave"
"github.com/hashicorp/consul/command/lock"
"github.com/hashicorp/consul/command/validate"
"github.com/hashicorp/consul/version"
"github.com/mitchellh/cli"
@ -122,13 +123,7 @@ func init() {
},
"lock": func() (cli.Command, error) {
return &LockCommand{
ShutdownCh: makeShutdownCh(),
BaseCommand: BaseCommand{
Flags: FlagSetHTTP,
UI: ui,
},
}, nil
return lock.New(ui), nil
},
"maint": func() (cli.Command, error) {

106
command/lock.go → command/lock/lock.go
View File

@ -1,6 +1,7 @@
package command
package lock
import (
"flag"
"fmt"
"os"
"os/exec"
@ -12,6 +13,8 @@ import (
"github.com/hashicorp/consul/agent"
"github.com/hashicorp/consul/api"
"github.com/hashicorp/consul/command/flags"
"github.com/mitchellh/cli"
)
const (
@ -35,8 +38,11 @@ const (
// LockCommand is a Command implementation that is used to setup
// a "lock" which manages lock acquisition and invokes a sub-process
type LockCommand struct {
BaseCommand
type cmd struct {
UI cli.Ui
flags *flag.FlagSet
http *flags.HTTPFlags
usage string
ShutdownCh <-chan struct{}
@ -54,49 +60,59 @@ type LockCommand struct {
timeout time.Duration
}
func (c *LockCommand) initFlags() {
c.InitFlagSet()
c.FlagSet.BoolVar(&c.propagateChildCode, "child-exit-code", false,
func New(ui cli.Ui) *cmd {
c := &cmd{UI: ui}
c.init()
return c
}
func (c *cmd) init() {
c.flags = flag.NewFlagSet("", flag.ContinueOnError)
c.flags.BoolVar(&c.propagateChildCode, "child-exit-code", false,
"Exit 2 if the child process exited with an error if this is true, "+
"otherwise this doesn't propagate an error from the child. The "+
"default value is false.")
c.FlagSet.IntVar(&c.limit, "n", 1,
c.flags.IntVar(&c.limit, "n", 1,
"Optional limit on the number of concurrent lock holders. The underlying "+
"implementation switches from a lock to a semaphore when the value is "+
"greater than 1. The default value is 1.")
c.FlagSet.IntVar(&c.monitorRetry, "monitor-retry", defaultMonitorRetry,
c.flags.IntVar(&c.monitorRetry, "monitor-retry", defaultMonitorRetry,
"Number of times to retry if Consul returns a 500 error while monitoring "+
"the lock. This allows riding out brief periods of unavailability "+
"without causing leader elections, but increases the amount of time "+
"required to detect a lost lock in some cases. The default value is 3, "+
"with a 1s wait between retries. Set this value to 0 to disable retires.")
c.FlagSet.StringVar(&c.name, "name", "",
c.flags.StringVar(&c.name, "name", "",
"Optional name to associate with the lock session. It not provided, one "+
"is generated based on the provided child command.")
c.FlagSet.BoolVar(&c.passStdin, "pass-stdin", false,
c.flags.BoolVar(&c.passStdin, "pass-stdin", false,
"Pass stdin to the child process.")
c.FlagSet.BoolVar(&c.shell, "shell", true,
c.flags.BoolVar(&c.shell, "shell", true,
"Use a shell to run the command (can set a custom shell via the SHELL "+
"environment variable).")
c.FlagSet.DurationVar(&c.timeout, "timeout", 0,
c.flags.DurationVar(&c.timeout, "timeout", 0,
"Maximum amount of time to wait to acquire the lock, specified as a "+
"duration like \"1s\" or \"3h\". The default value is 0.")
c.FlagSet.BoolVar(&c.verbose, "verbose", false,
c.flags.BoolVar(&c.verbose, "verbose", false,
"Enable verbose (debugging) output.")
// Deprecations
c.FlagSet.DurationVar(&c.timeout, "try", 0,
c.flags.DurationVar(&c.timeout, "try", 0,
"DEPRECATED. Use -timeout instead.")
c.http = &flags.HTTPFlags{}
flags.Merge(c.flags, c.http.ClientFlags())
flags.Merge(c.flags, c.http.ServerFlags())
c.usage = flags.Usage(usage, c.flags, c.http.ClientFlags(), c.http.ServerFlags())
}
func (c *LockCommand) Run(args []string) int {
func (c *cmd) Run(args []string) int {
var lu *LockUnlock
return c.run(args, &lu)
}
func (c *LockCommand) run(args []string, lu **LockUnlock) int {
c.initFlags()
if err := c.FlagSet.Parse(args); err != nil {
func (c *cmd) run(args []string, lu **LockUnlock) int {
if err := c.flags.Parse(args); err != nil {
return 1
}
@ -107,7 +123,7 @@ func (c *LockCommand) run(args []string, lu **LockUnlock) int {
}
// Verify the prefix and child are provided
extra := c.FlagSet.Args()
extra := c.flags.Args()
if len(extra) < 2 {
c.UI.Error("Key prefix and child command must be specified")
return 1
@ -135,7 +151,7 @@ func (c *LockCommand) run(args []string, lu **LockUnlock) int {
}
// Create and test the HTTP client
client, err := c.HTTPClient()
client, err := c.http.APIClient()
if err != nil {
c.UI.Error(fmt.Sprintf("Error connecting to Consul agent: %s", err))
return 1
@ -184,7 +200,7 @@ func (c *LockCommand) run(args []string, lu **LockUnlock) int {
// Start the child process
childErr = make(chan error, 1)
go func() {
childErr <- c.startChild(c.FlagSet.Args()[1:], c.passStdin, c.shell)
childErr <- c.startChild(c.flags.Args()[1:], c.passStdin, c.shell)
}()
// Monitor for shutdown, child termination, or lock loss
@ -249,7 +265,7 @@ RELEASE:
// up for a single attempt at acquisition, using the given wait time. The retry
// parameter sets how many 500 errors the lock monitor will tolerate before
// giving up the lock.
func (c *LockCommand) setupLock(client *api.Client, prefix, name string,
func (c *cmd) setupLock(client *api.Client, prefix, name string,
oneshot bool, wait time.Duration, retry int) (*LockUnlock, error) {
// Use the DefaultSemaphoreKey extension, this way if a lock and
// semaphore are both used at the same prefix, we will get a conflict
@ -287,7 +303,7 @@ func (c *LockCommand) setupLock(client *api.Client, prefix, name string,
// set up for a single attempt at acquisition, using the given wait time. The
// retry parameter sets how many 500 errors the lock monitor will tolerate
// before giving up the semaphore.
func (c *LockCommand) setupSemaphore(client *api.Client, limit int, prefix, name string,
func (c *cmd) setupSemaphore(client *api.Client, limit int, prefix, name string,
oneshot bool, wait time.Duration, retry int) (*LockUnlock, error) {
if c.verbose {
c.UI.Info(fmt.Sprintf("Setting up semaphore (limit %d) at prefix: %s", limit, prefix))
@ -319,7 +335,7 @@ func (c *LockCommand) setupSemaphore(client *api.Client, limit int, prefix, name
// startChild is a long running routine used to start and
// wait for the child process to exit.
func (c *LockCommand) startChild(args []string, passStdin, shell bool) error {
func (c *cmd) startChild(args []string, passStdin, shell bool) error {
if c.verbose {
c.UI.Info("Starting handler")
}
@ -385,7 +401,7 @@ func (c *LockCommand) startChild(args []string, passStdin, shell bool) error {
// termination.
// On Windows, the child is always hard terminated with a SIGKILL, even
// on the first attempt.
func (c *LockCommand) killChild(childErr chan error) error {
func (c *cmd) killChild(childErr chan error) error {
// Get the child process
child := c.child
@ -429,10 +445,25 @@ func (c *LockCommand) killChild(childErr chan error) error {
return nil
}
func (c *LockCommand) Help() string {
c.initFlags()
return c.HelpCommand(`
Usage: consul lock [options] prefix child...
func (c *cmd) Help() string {
return c.usage
}
func (c *cmd) Synopsis() string {
return "Execute a command holding a lock"
}
// LockUnlock is used to abstract over the differences between
// a lock and a semaphore.
type LockUnlock struct {
lockFn func(<-chan struct{}) (<-chan struct{}, error)
unlockFn func() error
cleanupFn func() error
inUseErr error
rawOpts interface{}
}
const usage = `Usage: consul lock [options] prefix child...
Acquires a lock or semaphore at a given path, and invokes a child process
when successful. The child process can assume the lock is held while it
@ -449,19 +480,4 @@ Usage: consul lock [options] prefix child...
The prefix provided must have write privileges.
`)
}
func (c *LockCommand) Synopsis() string {
return "Execute a command holding a lock"
}
// LockUnlock is used to abstract over the differences between
// a lock and a semaphore.
type LockUnlock struct {
lockFn func(<-chan struct{}) (<-chan struct{}, error)
unlockFn func() error
cleanupFn func() error
inUseErr error
rawOpts interface{}
}
`

62
command/lock_test.go → command/lock/lock_test.go
View File

@ -1,4 +1,4 @@
package command
package lock
import (
"io/ioutil"
@ -12,23 +12,10 @@ import (
"github.com/mitchellh/cli"
)
func testLockCommand(t *testing.T) (*cli.MockUi, *LockCommand) {
ui := cli.NewMockUi()
return ui, &LockCommand{
BaseCommand: BaseCommand{
UI: ui,
Flags: FlagSetHTTP,
},
}
}
func TestLockCommand_implements(t *testing.T) {
t.Parallel()
var _ cli.Command = &LockCommand{}
}
func argFail(t *testing.T, args []string, expected string) {
ui, c := testLockCommand(t)
ui := cli.NewMockUi()
c := New(ui)
c.flags.SetOutput(ui.ErrorWriter)
if code := c.Run(args); code != 1 {
t.Fatalf("expected return code 1, got %d", code)
}
@ -50,7 +37,9 @@ func TestLockCommand_Run(t *testing.T) {
a := agent.NewTestAgent(t.Name(), ``)
defer a.Shutdown()
ui, c := testLockCommand(t)
ui := cli.NewMockUi()
c := New(ui)
filePath := filepath.Join(a.Config.DataDir, "test_touch")
args := []string{"-http-addr=" + a.HTTPAddr(), "test/prefix", "touch", filePath}
@ -71,7 +60,9 @@ func TestLockCommand_Run_NoShell(t *testing.T) {
a := agent.NewTestAgent(t.Name(), ``)
defer a.Shutdown()
ui, c := testLockCommand(t)
ui := cli.NewMockUi()
c := New(ui)
filePath := filepath.Join(a.Config.DataDir, "test_touch")
args := []string{"-http-addr=" + a.HTTPAddr(), "-shell=false", "test/prefix", "touch", filePath}
@ -92,7 +83,9 @@ func TestLockCommand_Try_Lock(t *testing.T) {
a := agent.NewTestAgent(t.Name(), ``)
defer a.Shutdown()
ui, c := testLockCommand(t)
ui := cli.NewMockUi()
c := New(ui)
filePath := filepath.Join(a.Config.DataDir, "test_touch")
args := []string{"-http-addr=" + a.HTTPAddr(), "-try=10s", "test/prefix", "touch", filePath}
@ -122,7 +115,9 @@ func TestLockCommand_Try_Semaphore(t *testing.T) {
a := agent.NewTestAgent(t.Name(), ``)
defer a.Shutdown()
ui, c := testLockCommand(t)
ui := cli.NewMockUi()
c := New(ui)
filePath := filepath.Join(a.Config.DataDir, "test_touch")
args := []string{"-http-addr=" + a.HTTPAddr(), "-n=3", "-try=10s", "test/prefix", "touch", filePath}
@ -152,7 +147,9 @@ func TestLockCommand_MonitorRetry_Lock_Default(t *testing.T) {
a := agent.NewTestAgent(t.Name(), ``)
defer a.Shutdown()
ui, c := testLockCommand(t)
ui := cli.NewMockUi()
c := New(ui)
filePath := filepath.Join(a.Config.DataDir, "test_touch")
args := []string{"-http-addr=" + a.HTTPAddr(), "test/prefix", "touch", filePath}
@ -183,7 +180,9 @@ func TestLockCommand_MonitorRetry_Semaphore_Default(t *testing.T) {
a := agent.NewTestAgent(t.Name(), ``)
defer a.Shutdown()
ui, c := testLockCommand(t)
ui := cli.NewMockUi()
c := New(ui)
filePath := filepath.Join(a.Config.DataDir, "test_touch")
args := []string{"-http-addr=" + a.HTTPAddr(), "-n=3", "test/prefix", "touch", filePath}
@ -214,7 +213,9 @@ func TestLockCommand_MonitorRetry_Lock_Arg(t *testing.T) {
a := agent.NewTestAgent(t.Name(), ``)
defer a.Shutdown()
ui, c := testLockCommand(t)
ui := cli.NewMockUi()
c := New(ui)
filePath := filepath.Join(a.Config.DataDir, "test_touch")
args := []string{"-http-addr=" + a.HTTPAddr(), "-monitor-retry=9", "test/prefix", "touch", filePath}
@ -245,7 +246,9 @@ func TestLockCommand_MonitorRetry_Semaphore_Arg(t *testing.T) {
a := agent.NewTestAgent(t.Name(), ``)
defer a.Shutdown()
ui, c := testLockCommand(t)
ui := cli.NewMockUi()
c := New(ui)
filePath := filepath.Join(a.Config.DataDir, "test_touch")
args := []string{"-http-addr=" + a.HTTPAddr(), "-n=3", "-monitor-retry=9", "test/prefix", "touch", filePath}
@ -277,7 +280,8 @@ func TestLockCommand_ChildExitCode(t *testing.T) {
defer a.Shutdown()
t.Run("clean exit", func(t *testing.T) {
_, c := testLockCommand(t)
ui := cli.NewMockUi()
c := New(ui)
args := []string{"-http-addr=" + a.HTTPAddr(), "-child-exit-code", "test/prefix", "sh", "-c", "exit", "0"}
if got, want := c.Run(args), 0; got != want {
t.Fatalf("got %d want %d", got, want)
@ -285,7 +289,8 @@ func TestLockCommand_ChildExitCode(t *testing.T) {
})
t.Run("error exit", func(t *testing.T) {
_, c := testLockCommand(t)
ui := cli.NewMockUi()
c := New(ui)
args := []string{"-http-addr=" + a.HTTPAddr(), "-child-exit-code", "test/prefix", "exit", "1"}
if got, want := c.Run(args), 2; got != want {
t.Fatalf("got %d want %d", got, want)
@ -293,7 +298,8 @@ func TestLockCommand_ChildExitCode(t *testing.T) {
})
t.Run("not propagated", func(t *testing.T) {
_, c := testLockCommand(t)
ui := cli.NewMockUi()
c := New(ui)
args := []string{"-http-addr=" + a.HTTPAddr(), "test/prefix", "sh", "-c", "exit", "1"}
if got, want := c.Run(args), 0; got != want {
t.Fatalf("got %d want %d", got, want)

2
command/util_unix.go → command/lock/util_unix.go
View File

@ -1,6 +1,6 @@
// +build !windows
package command
package lock
import (
"syscall"

2
command/util_windows.go → command/lock/util_windows.go
View File

@ -1,6 +1,6 @@
// +build windows
package command
package lock
import (
"os"