Added implementation to run checks for docker, exec and raw_exec

client/driver/executor/checks.go

@@ -0,0 +1,237 @@
+package executor
+
+import (
+	"container/heap"
+	"fmt"
+	"log"
+	"os/exec"
+	"syscall"
+	"time"
+
+	"github.com/armon/circbuf"
+	docker "github.com/fsouza/go-dockerclient"
+
+	cstructs "github.com/hashicorp/nomad/client/driver/structs"
+)
+
+type Check interface {
+	Run() *cstructs.CheckResult
+	ID() string
+}
+
+type DockerScriptCheck struct {
+	id          string
+	containerID string
+	client      *docker.Client
+	logger      *log.Logger
+	script      []string
+}
+
+func (d *DockerScriptCheck) Run() *cstructs.CheckResult {
+	execOpts := docker.CreateExecOptions{
+		AttachStdin:  false,
+		AttachStdout: true,
+		AttachStderr: true,
+		Tty:          false,
+		Cmd:          d.script,
+		Container:    d.containerID,
+	}
+	var (
+		exec    *docker.Exec
+		err     error
+		execRes *docker.ExecInspect
+		time    = time.Now()
+	)
+	if exec, err = d.client.CreateExec(execOpts); err != nil {
+		return &cstructs.CheckResult{Err: err}
+	}
+
+	output, _ := circbuf.NewBuffer(int64(cstructs.CheckBufSize))
+	startOpts := docker.StartExecOptions{
+		Detach:       false,
+		Tty:          false,
+		OutputStream: output,
+		ErrorStream:  output,
+	}
+
+	if err = d.client.StartExec(exec.ID, startOpts); err != nil {
+		return &cstructs.CheckResult{Err: err}
+	}
+	if execRes, err = d.client.InspectExec(exec.ID); err != nil {
+		return &cstructs.CheckResult{Err: err}
+	}
+	return &cstructs.CheckResult{
+		ExitCode:  execRes.ExitCode,
+		Output:    string(output.Bytes()),
+		Timestamp: time,
+	}
+}
+
+func (d *DockerScriptCheck) ID() string {
+	return d.id
+}
+
+type ExecScriptCheck struct {
+	id      string
+	cmd     string
+	args    []string
+	taskDir string
+
+	ctx         *ExecutorContext
+	FSIsolation bool
+}
+
+func (e *ExecScriptCheck) Run() *cstructs.CheckResult {
+	buf, _ := circbuf.NewBuffer(int64(cstructs.CheckBufSize))
+	cmd := exec.Command(e.cmd, e.args...)
+	cmd.Stdout = buf
+	cmd.Stderr = buf
+	e.setChroot(cmd)
+	ts := time.Now()
+	if err := cmd.Start(); err != nil {
+		return &cstructs.CheckResult{Err: err}
+	}
+	errCh := make(chan error, 2)
+	go func() {
+		errCh <- cmd.Wait()
+	}()
+	for {
+		select {
+		case err := <-errCh:
+			if err == nil {
+				return &cstructs.CheckResult{ExitCode: 0, Output: string(buf.Bytes()), Timestamp: ts}
+			}
+			exitCode := 1
+			if exitErr, ok := err.(*exec.ExitError); ok {
+				if status, ok := exitErr.Sys().(syscall.WaitStatus); ok {
+					exitCode = status.ExitStatus()
+				}
+			}
+			return &cstructs.CheckResult{ExitCode: exitCode, Output: string(buf.Bytes()), Timestamp: ts}
+		case <-time.After(30 * time.Second):
+			errCh <- fmt.Errorf("timed out after waiting 30s")
+		}
+	}
+	return nil
+}
+
+func (e *ExecScriptCheck) ID() string {
+	return e.id
+}
+
+type consulCheck struct {
+	check Check
+	next  time.Time
+	index int
+}
+
+type checkHeap struct {
+	index map[string]*consulCheck
+	heap  checksHeapImp
+}
+
+func NewConsulChecksHeap() *checkHeap {
+	return &checkHeap{
+		index: make(map[string]*consulCheck),
+		heap:  make(checksHeapImp, 0),
+	}
+}
+
+func (c *checkHeap) Push(check Check, next time.Time) error {
+	if _, ok := c.index[check.ID()]; ok {
+		return fmt.Errorf("check %v already exists", check.ID())
+	}
+
+	cCheck := &consulCheck{check, next, 0}
+
+	c.index[check.ID()] = cCheck
+	heap.Push(&c.heap, cCheck)
+	return nil
+}
+
+func (c *checkHeap) Pop() *consulCheck {
+	if len(c.heap) == 0 {
+		return nil
+	}
+
+	cCheck := heap.Pop(&c.heap).(*consulCheck)
+	delete(c.index, cCheck.check.ID())
+	return cCheck
+}
+
+func (c *checkHeap) Peek() *consulCheck {
+	if len(c.heap) == 0 {
+		return nil
+	}
+	return c.heap[0]
+}
+
+func (c *checkHeap) Contains(check Check) bool {
+	_, ok := c.index[check.ID()]
+	return ok
+}
+
+func (c *checkHeap) Update(check Check, next time.Time) error {
+	if cCheck, ok := c.index[check.ID()]; ok {
+		cCheck.check = check
+		cCheck.next = next
+		heap.Fix(&c.heap, cCheck.index)
+		return nil
+	}
+
+	return fmt.Errorf("heap doesn't contain check %v", check.ID())
+}
+
+func (c *checkHeap) Remove(check Check) error {
+	if cCheck, ok := c.index[check.ID()]; ok {
+		heap.Remove(&c.heap, cCheck.index)
+		delete(c.index, check.ID())
+		return nil
+	}
+	return fmt.Errorf("heap doesn't contain check %v", check.ID())
+}
+
+func (c *checkHeap) Len() int { return len(c.heap) }
+
+type checksHeapImp []*consulCheck
+
+func (h checksHeapImp) Len() int { return len(h) }
+
+func (h checksHeapImp) Less(i, j int) bool {
+	// Two zero times should return false.
+	// Otherwise, zero is "greater" than any other time.
+	// (To sort it at the end of the list.)
+	// Sort such that zero times are at the end of the list.
+	iZero, jZero := h[i].next.IsZero(), h[j].next.IsZero()
+	if iZero && jZero {
+		return false
+	} else if iZero {
+		return false
+	} else if jZero {
+		return true
+	}
+
+	return h[i].next.Before(h[j].next)
+}
+
+func (h checksHeapImp) Swap(i, j int) {
+	h[i], h[j] = h[j], h[i]
+	h[i].index = i
+	h[j].index = j
+}
+
+func (h *checksHeapImp) Push(x interface{}) {
+	n := len(*h)
+	check := x.(*consulCheck)
+	check.index = n
+	*h = append(*h, check)
+}
+
+func (h *checksHeapImp) Pop() interface{} {
+	old := *h
+	n := len(old)
+	check := old[n-1]
+	check.index = -1 // for safety
+	*h = old[0 : n-1]
+	return check
+}

client/driver/executor/checks_basic.go

@@ -0,0 +1,10 @@
+// +build !linux
+
+package executor
+
+import (
+	"os/exec"
+)
+
+func (e *ExecScriptCheck) setChroot(cmd *exec.Cmd) {
+}

client/driver/executor/checks_linux.go

@@ -0,0 +1,16 @@
+package executor
+
+import (
+	"os/exec"
+	"syscall"
+)
+
+func (e *ExecScriptCheck) setChroot(cmd *exec.Cmd) {
+	if e.FSIsolation {
+		if cmd.SysProcAttr == nil {
+			cmd.SysProcAttr = &syscall.SysProcAttr{}
+		}
+	}
+	cmd.SysProcAttr.Chroot = e.taskDir
+	cmd.Dir = "/"
+}

client/driver/executor/checks_test.go

@@ -0,0 +1,37 @@
+package executor
+
+import (
+	"reflect"
+	"testing"
+	"time"
+)
+
+func TestCheckHeapOrder(t *testing.T) {
+	h := NewConsulChecksHeap()
+
+	c1 := ExecScriptCheck{id: "a"}
+	c2 := ExecScriptCheck{id: "b"}
+	c3 := ExecScriptCheck{id: "c"}
+
+	lookup := map[Check]string{
+		&c1: "c1",
+		&c2: "c2",
+		&c3: "c3",
+	}
+
+	h.Push(&c1, time.Time{})
+	h.Push(&c2, time.Unix(10, 0))
+	h.Push(&c3, time.Unix(11, 0))
+
+	expected := []string{"c2", "c3", "c1"}
+	var actual []string
+	for i := 0; i < 3; i++ {
+		cCheck := h.Pop()
+
+		actual = append(actual, lookup[cCheck.check])
+	}
+
+	if !reflect.DeepEqual(actual, expected) {
+		t.Fatalf("Wrong ordering; got %v; want %v", actual, expected)
+	}
+}

client/driver/structs/structs.go

@@ -2,6 +2,7 @@ package structs
 
 import (
 	"fmt"
+	"time"
 
 	cgroupConfig "github.com/opencontainers/runc/libcontainer/configs"
 )
@@ -9,6 +10,9 @@ import (
 const (
 	// The default user that the executor uses to run tasks
 	DefaultUnpriviledgedUser = "nobody"
+
+	// CheckBufSize is the size of the check output result
+	CheckBufSize = 4 * 1024
 )
 
 // WaitResult stores the result of a Wait operation.
@@ -60,3 +64,11 @@ func NewRecoverableError(e error, recoverable bool) *RecoverableError {
 func (r *RecoverableError) Error() string {
 	return r.Err.Error()
 }
+
+// CheckResult encapsulates the result of a check
+type CheckResult struct {
+	ExitCode  int
+	Output    string
+	Timestamp time.Time
+	Err       error
+}