643 lines
16 KiB
Go
643 lines
16 KiB
Go
package agent
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import (
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"crypto/tls"
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"fmt"
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"io"
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"io/ioutil"
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"log"
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"net"
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"net/http"
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"os"
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"os/exec"
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"sync"
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"syscall"
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"time"
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"github.com/armon/circbuf"
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"github.com/hashicorp/consul/agent/structs"
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"github.com/hashicorp/consul/api"
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"github.com/hashicorp/consul/lib"
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"github.com/hashicorp/consul/types"
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"github.com/hashicorp/go-cleanhttp"
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)
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const (
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// MinInterval is the minimal interval between
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// two checks. Do not allow for a interval below this value.
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// Otherwise we risk fork bombing a system.
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MinInterval = time.Second
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// CheckBufSize is the maximum size of the captured
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// check output. Prevents an enormous buffer
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// from being captured
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CheckBufSize = 4 * 1024 // 4KB
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// UserAgent is the value of the User-Agent header
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// for HTTP health checks.
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UserAgent = "Consul Health Check"
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)
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// CheckNotifier interface is used by the CheckMonitor
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// to notify when a check has a status update. The update
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// should take care to be idempotent.
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type CheckNotifier interface {
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UpdateCheck(checkID types.CheckID, status, output string)
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}
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// CheckMonitor is used to periodically invoke a script to
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// determine the health of a given check. It is compatible with
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// nagios plugins and expects the output in the same format.
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type CheckMonitor struct {
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Notify CheckNotifier
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CheckID types.CheckID
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Script string
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ScriptArgs []string
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Interval time.Duration
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Timeout time.Duration
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Logger *log.Logger
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stop bool
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stopCh chan struct{}
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stopLock sync.Mutex
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}
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// Start is used to start a check monitor.
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// Monitor runs until stop is called
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func (c *CheckMonitor) Start() {
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c.stopLock.Lock()
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defer c.stopLock.Unlock()
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c.stop = false
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c.stopCh = make(chan struct{})
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go c.run()
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}
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// Stop is used to stop a check monitor.
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func (c *CheckMonitor) Stop() {
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c.stopLock.Lock()
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defer c.stopLock.Unlock()
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if !c.stop {
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c.stop = true
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close(c.stopCh)
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}
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}
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// run is invoked by a goroutine to run until Stop() is called
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func (c *CheckMonitor) run() {
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// Get the randomized initial pause time
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initialPauseTime := lib.RandomStagger(c.Interval)
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c.Logger.Printf("[DEBUG] agent: pausing %v before first invocation of %s", initialPauseTime, c.Script)
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next := time.After(initialPauseTime)
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for {
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select {
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case <-next:
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c.check()
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next = time.After(c.Interval)
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case <-c.stopCh:
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return
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}
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}
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}
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// check is invoked periodically to perform the script check
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func (c *CheckMonitor) check() {
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// Create the command
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var cmd *exec.Cmd
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var err error
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if len(c.ScriptArgs) > 0 {
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cmd, err = ExecSubprocess(c.ScriptArgs)
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} else {
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cmd, err = ExecScript(c.Script)
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}
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if err != nil {
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c.Logger.Printf("[ERR] agent: failed to setup invoke '%s': %s", c.Script, err)
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c.Notify.UpdateCheck(c.CheckID, api.HealthCritical, err.Error())
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return
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}
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// Collect the output
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output, _ := circbuf.NewBuffer(CheckBufSize)
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cmd.Stdout = output
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cmd.Stderr = output
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// Start the check
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if err := cmd.Start(); err != nil {
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c.Logger.Printf("[ERR] agent: failed to invoke '%s': %s", c.Script, err)
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c.Notify.UpdateCheck(c.CheckID, api.HealthCritical, err.Error())
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return
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}
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// Wait for the check to complete
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errCh := make(chan error, 2)
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go func() {
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errCh <- cmd.Wait()
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}()
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go func() {
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if c.Timeout > 0 {
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time.Sleep(c.Timeout)
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} else {
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time.Sleep(30 * time.Second)
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}
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errCh <- fmt.Errorf("Timed out running check '%s'", c.Script)
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}()
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err = <-errCh
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// Get the output, add a message about truncation
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outputStr := string(output.Bytes())
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if output.TotalWritten() > output.Size() {
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outputStr = fmt.Sprintf("Captured %d of %d bytes\n...\n%s",
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output.Size(), output.TotalWritten(), outputStr)
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}
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c.Logger.Printf("[DEBUG] agent: Check '%s' script '%s' output: %s",
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c.CheckID, c.Script, outputStr)
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// Check if the check passed
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if err == nil {
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c.Logger.Printf("[DEBUG] agent: Check '%v' is passing", c.CheckID)
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c.Notify.UpdateCheck(c.CheckID, api.HealthPassing, outputStr)
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return
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}
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// If the exit code is 1, set check as warning
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exitErr, ok := err.(*exec.ExitError)
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if ok {
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if status, ok := exitErr.Sys().(syscall.WaitStatus); ok {
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code := status.ExitStatus()
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if code == 1 {
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c.Logger.Printf("[WARN] agent: Check '%v' is now warning", c.CheckID)
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c.Notify.UpdateCheck(c.CheckID, api.HealthWarning, outputStr)
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return
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}
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}
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}
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// Set the health as critical
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c.Logger.Printf("[WARN] agent: Check '%v' is now critical", c.CheckID)
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c.Notify.UpdateCheck(c.CheckID, api.HealthCritical, outputStr)
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}
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// CheckTTL is used to apply a TTL to check status,
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// and enables clients to set the status of a check
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// but upon the TTL expiring, the check status is
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// automatically set to critical.
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type CheckTTL struct {
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Notify CheckNotifier
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CheckID types.CheckID
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TTL time.Duration
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Logger *log.Logger
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timer *time.Timer
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lastOutput string
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lastOutputLock sync.RWMutex
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stop bool
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stopCh chan struct{}
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stopLock sync.Mutex
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}
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// Start is used to start a check ttl, runs until Stop()
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func (c *CheckTTL) Start() {
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c.stopLock.Lock()
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defer c.stopLock.Unlock()
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c.stop = false
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c.stopCh = make(chan struct{})
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c.timer = time.NewTimer(c.TTL)
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go c.run()
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}
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// Stop is used to stop a check ttl.
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func (c *CheckTTL) Stop() {
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c.stopLock.Lock()
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defer c.stopLock.Unlock()
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if !c.stop {
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c.timer.Stop()
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c.stop = true
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close(c.stopCh)
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}
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}
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// run is used to handle TTL expiration and to update the check status
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func (c *CheckTTL) run() {
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for {
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select {
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case <-c.timer.C:
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c.Logger.Printf("[WARN] agent: Check '%v' missed TTL, is now critical",
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c.CheckID)
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c.Notify.UpdateCheck(c.CheckID, api.HealthCritical, c.getExpiredOutput())
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case <-c.stopCh:
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return
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}
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}
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}
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// getExpiredOutput formats the output for the case when the TTL is expired.
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func (c *CheckTTL) getExpiredOutput() string {
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c.lastOutputLock.RLock()
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defer c.lastOutputLock.RUnlock()
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const prefix = "TTL expired"
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if c.lastOutput == "" {
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return prefix
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}
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return fmt.Sprintf("%s (last output before timeout follows): %s", prefix, c.lastOutput)
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}
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// SetStatus is used to update the status of the check,
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// and to renew the TTL. If expired, TTL is restarted.
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func (c *CheckTTL) SetStatus(status, output string) {
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c.Logger.Printf("[DEBUG] agent: Check '%v' status is now %v",
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c.CheckID, status)
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c.Notify.UpdateCheck(c.CheckID, status, output)
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// Store the last output so we can retain it if the TTL expires.
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c.lastOutputLock.Lock()
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c.lastOutput = output
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c.lastOutputLock.Unlock()
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c.timer.Reset(c.TTL)
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}
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// persistedCheck is used to serialize a check and write it to disk
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// so that it may be restored later on.
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type persistedCheck struct {
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Check *structs.HealthCheck
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ChkType *structs.CheckType
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Token string
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}
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// persistedCheckState is used to persist the current state of a given
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// check. This is different from the check definition, and includes an
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// expiration timestamp which is used to determine staleness on later
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// agent restarts.
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type persistedCheckState struct {
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CheckID types.CheckID
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Output string
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Status string
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Expires int64
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}
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// CheckHTTP is used to periodically make an HTTP request to
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// determine the health of a given check.
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// The check is passing if the response code is 2XX.
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// The check is warning if the response code is 429.
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// The check is critical if the response code is anything else
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// or if the request returns an error
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type CheckHTTP struct {
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Notify CheckNotifier
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CheckID types.CheckID
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HTTP string
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Header map[string][]string
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Method string
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Interval time.Duration
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Timeout time.Duration
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Logger *log.Logger
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TLSSkipVerify bool
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httpClient *http.Client
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stop bool
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stopCh chan struct{}
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stopLock sync.Mutex
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}
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// Start is used to start an HTTP check.
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// The check runs until stop is called
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func (c *CheckHTTP) Start() {
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c.stopLock.Lock()
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defer c.stopLock.Unlock()
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if c.httpClient == nil {
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// Create the transport. We disable HTTP Keep-Alive's to prevent
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// failing checks due to the keepalive interval.
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trans := cleanhttp.DefaultTransport()
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trans.DisableKeepAlives = true
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// Skip SSL certificate verification if TLSSkipVerify is true
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if trans.TLSClientConfig == nil {
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trans.TLSClientConfig = &tls.Config{
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InsecureSkipVerify: c.TLSSkipVerify,
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}
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} else {
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trans.TLSClientConfig.InsecureSkipVerify = c.TLSSkipVerify
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}
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// Create the HTTP client.
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c.httpClient = &http.Client{
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Timeout: 10 * time.Second,
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Transport: trans,
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}
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// For long (>10s) interval checks the http timeout is 10s, otherwise the
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// timeout is the interval. This means that a check *should* return
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// before the next check begins.
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if c.Timeout > 0 && c.Timeout < c.Interval {
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c.httpClient.Timeout = c.Timeout
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} else if c.Interval < 10*time.Second {
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c.httpClient.Timeout = c.Interval
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}
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}
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c.stop = false
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c.stopCh = make(chan struct{})
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go c.run()
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}
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// Stop is used to stop an HTTP check.
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func (c *CheckHTTP) Stop() {
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c.stopLock.Lock()
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defer c.stopLock.Unlock()
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if !c.stop {
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c.stop = true
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close(c.stopCh)
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}
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}
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// run is invoked by a goroutine to run until Stop() is called
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func (c *CheckHTTP) run() {
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// Get the randomized initial pause time
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initialPauseTime := lib.RandomStagger(c.Interval)
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c.Logger.Printf("[DEBUG] agent: pausing %v before first HTTP request of %s", initialPauseTime, c.HTTP)
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next := time.After(initialPauseTime)
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for {
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select {
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case <-next:
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c.check()
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next = time.After(c.Interval)
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case <-c.stopCh:
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return
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}
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}
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}
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// check is invoked periodically to perform the HTTP check
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func (c *CheckHTTP) check() {
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method := c.Method
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if method == "" {
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method = "GET"
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}
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req, err := http.NewRequest(method, c.HTTP, nil)
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if err != nil {
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c.Logger.Printf("[WARN] agent: http request failed '%s': %s", c.HTTP, err)
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c.Notify.UpdateCheck(c.CheckID, api.HealthCritical, err.Error())
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return
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}
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req.Header = http.Header(c.Header)
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// this happens during testing but not in prod
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if req.Header == nil {
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req.Header = make(http.Header)
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}
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if host := req.Header.Get("Host"); host != "" {
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req.Host = host
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}
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if req.Header.Get("User-Agent") == "" {
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req.Header.Set("User-Agent", UserAgent)
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}
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if req.Header.Get("Accept") == "" {
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req.Header.Set("Accept", "text/plain, text/*, */*")
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}
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resp, err := c.httpClient.Do(req)
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if err != nil {
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c.Logger.Printf("[WARN] agent: http request failed '%s': %s", c.HTTP, err)
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c.Notify.UpdateCheck(c.CheckID, api.HealthCritical, err.Error())
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return
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}
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defer resp.Body.Close()
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// Read the response into a circular buffer to limit the size
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output, _ := circbuf.NewBuffer(CheckBufSize)
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if _, err := io.Copy(output, resp.Body); err != nil {
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c.Logger.Printf("[WARN] agent: Check '%v': Get error while reading body: %s", c.CheckID, err)
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}
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// Format the response body
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result := fmt.Sprintf("HTTP GET %s: %s Output: %s", c.HTTP, resp.Status, output.String())
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if resp.StatusCode >= 200 && resp.StatusCode <= 299 {
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// PASSING (2xx)
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c.Logger.Printf("[DEBUG] agent: Check '%v' is passing", c.CheckID)
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c.Notify.UpdateCheck(c.CheckID, api.HealthPassing, result)
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} else if resp.StatusCode == 429 {
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// WARNING
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// 429 Too Many Requests (RFC 6585)
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// The user has sent too many requests in a given amount of time.
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c.Logger.Printf("[WARN] agent: Check '%v' is now warning", c.CheckID)
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c.Notify.UpdateCheck(c.CheckID, api.HealthWarning, result)
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} else {
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// CRITICAL
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c.Logger.Printf("[WARN] agent: Check '%v' is now critical", c.CheckID)
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c.Notify.UpdateCheck(c.CheckID, api.HealthCritical, result)
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}
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}
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// CheckTCP is used to periodically make an TCP/UDP connection to
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// determine the health of a given check.
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// The check is passing if the connection succeeds
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// The check is critical if the connection returns an error
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type CheckTCP struct {
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Notify CheckNotifier
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CheckID types.CheckID
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TCP string
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Interval time.Duration
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Timeout time.Duration
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Logger *log.Logger
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dialer *net.Dialer
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stop bool
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stopCh chan struct{}
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stopLock sync.Mutex
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}
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// Start is used to start a TCP check.
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// The check runs until stop is called
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func (c *CheckTCP) Start() {
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c.stopLock.Lock()
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defer c.stopLock.Unlock()
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if c.dialer == nil {
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// Create the socket dialer
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c.dialer = &net.Dialer{DualStack: true}
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// For long (>10s) interval checks the socket timeout is 10s, otherwise
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// the timeout is the interval. This means that a check *should* return
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// before the next check begins.
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if c.Timeout > 0 && c.Timeout < c.Interval {
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c.dialer.Timeout = c.Timeout
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} else if c.Interval < 10*time.Second {
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c.dialer.Timeout = c.Interval
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}
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}
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c.stop = false
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c.stopCh = make(chan struct{})
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go c.run()
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}
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// Stop is used to stop a TCP check.
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func (c *CheckTCP) Stop() {
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c.stopLock.Lock()
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defer c.stopLock.Unlock()
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if !c.stop {
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c.stop = true
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close(c.stopCh)
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}
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}
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// run is invoked by a goroutine to run until Stop() is called
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func (c *CheckTCP) run() {
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// Get the randomized initial pause time
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initialPauseTime := lib.RandomStagger(c.Interval)
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c.Logger.Printf("[DEBUG] agent: pausing %v before first socket connection of %s", initialPauseTime, c.TCP)
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next := time.After(initialPauseTime)
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for {
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select {
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case <-next:
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c.check()
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next = time.After(c.Interval)
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case <-c.stopCh:
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return
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}
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}
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}
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// check is invoked periodically to perform the TCP check
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func (c *CheckTCP) check() {
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conn, err := c.dialer.Dial(`tcp`, c.TCP)
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if err != nil {
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c.Logger.Printf("[WARN] agent: socket connection failed '%s': %s", c.TCP, err)
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c.Notify.UpdateCheck(c.CheckID, api.HealthCritical, err.Error())
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return
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}
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conn.Close()
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c.Logger.Printf("[DEBUG] agent: Check '%v' is passing", c.CheckID)
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c.Notify.UpdateCheck(c.CheckID, api.HealthPassing, fmt.Sprintf("TCP connect %s: Success", c.TCP))
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}
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|
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// CheckDocker is used to periodically invoke a script to
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// determine the health of an application running inside a
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// Docker Container. We assume that the script is compatible
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// with nagios plugins and expects the output in the same format.
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type CheckDocker struct {
|
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Notify CheckNotifier
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CheckID types.CheckID
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Script string
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ScriptArgs []string
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DockerContainerID string
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Shell string
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Interval time.Duration
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Logger *log.Logger
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client *DockerClient
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stop chan struct{}
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}
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func (c *CheckDocker) Start() {
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if c.stop != nil {
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panic("Docker check already started")
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}
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|
|
if c.Logger == nil {
|
|
c.Logger = log.New(ioutil.Discard, "", 0)
|
|
}
|
|
|
|
if c.Shell == "" {
|
|
c.Shell = os.Getenv("SHELL")
|
|
if c.Shell == "" {
|
|
c.Shell = "/bin/sh"
|
|
}
|
|
}
|
|
c.stop = make(chan struct{})
|
|
go c.run()
|
|
}
|
|
|
|
func (c *CheckDocker) Stop() {
|
|
if c.stop == nil {
|
|
panic("Stop called before start")
|
|
}
|
|
close(c.stop)
|
|
}
|
|
|
|
func (c *CheckDocker) run() {
|
|
firstWait := lib.RandomStagger(c.Interval)
|
|
c.Logger.Printf("[DEBUG] agent: pausing %v before first invocation of %s -c %s in container %s", firstWait, c.Shell, c.Script, c.DockerContainerID)
|
|
next := time.After(firstWait)
|
|
for {
|
|
select {
|
|
case <-next:
|
|
c.check()
|
|
next = time.After(c.Interval)
|
|
case <-c.stop:
|
|
return
|
|
}
|
|
}
|
|
}
|
|
|
|
func (c *CheckDocker) check() {
|
|
var out string
|
|
status, b, err := c.doCheck()
|
|
if err != nil {
|
|
c.Logger.Printf("[DEBUG] agent: Check '%s': %s", c.CheckID, err)
|
|
out = err.Error()
|
|
} else {
|
|
// out is already limited to CheckBufSize since we're getting a
|
|
// limited buffer. So we don't need to truncate it just report
|
|
// that it was truncated.
|
|
out = string(b.Bytes())
|
|
if int(b.TotalWritten()) > len(out) {
|
|
out = fmt.Sprintf("Captured %d of %d bytes\n...\n%s", len(out), b.TotalWritten(), out)
|
|
}
|
|
c.Logger.Printf("[DEBUG] agent: Check '%s' script '%s' output: %s", c.CheckID, c.Script, out)
|
|
}
|
|
|
|
if status == api.HealthCritical {
|
|
c.Logger.Printf("[WARN] agent: Check '%v' is now critical", c.CheckID)
|
|
}
|
|
|
|
c.Notify.UpdateCheck(c.CheckID, status, out)
|
|
}
|
|
|
|
func (c *CheckDocker) doCheck() (string, *circbuf.Buffer, error) {
|
|
var cmd []string
|
|
if len(c.ScriptArgs) > 0 {
|
|
cmd = c.ScriptArgs
|
|
} else {
|
|
cmd = []string{c.Shell, "-c", c.Script}
|
|
}
|
|
|
|
execID, err := c.client.CreateExec(c.DockerContainerID, cmd)
|
|
if err != nil {
|
|
return api.HealthCritical, nil, err
|
|
}
|
|
|
|
buf, err := c.client.StartExec(c.DockerContainerID, execID)
|
|
if err != nil {
|
|
return api.HealthCritical, nil, err
|
|
}
|
|
|
|
exitCode, err := c.client.InspectExec(c.DockerContainerID, execID)
|
|
if err != nil {
|
|
return api.HealthCritical, nil, err
|
|
}
|
|
|
|
switch exitCode {
|
|
case 0:
|
|
return api.HealthPassing, buf, nil
|
|
case 1:
|
|
c.Logger.Printf("[DEBUG] Check failed with exit code: %d", exitCode)
|
|
return api.HealthWarning, buf, nil
|
|
default:
|
|
c.Logger.Printf("[DEBUG] Check failed with exit code: %d", exitCode)
|
|
return api.HealthCritical, buf, nil
|
|
}
|
|
}
|