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Refactor IdleTracker to handle StateIdle transitions 

* Remove stutter naming for package and types
* Stop treating StateIdle the same as StateClosed, rather transitions to
  StateIdle will keep API timeout window open
* Remove redundate code

Fixes #7826

Signed-off-by: Jhon Honce <jhonce@redhat.com>
This commit is contained in:
Jhon Honce 2020-09-29 11:32:47 -07:00
parent 2ee415be90
commit f03d470349
5 changed files with 113 additions and 91 deletions
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6
pkg/api/handlers/compat/containers_attach.go
View File

@ -6,7 +6,7 @@ import (
"github.com/containers/podman/v2/libpod"
"github.com/containers/podman/v2/libpod/define"
"github.com/containers/podman/v2/pkg/api/handlers/utils"
"github.com/containers/podman/v2/pkg/api/server/idletracker"
"github.com/containers/podman/v2/pkg/api/server/idle"
"github.com/gorilla/schema"
"github.com/pkg/errors"
"github.com/sirupsen/logrus"
@ -92,7 +92,7 @@ func AttachContainer(w http.ResponseWriter, r *http.Request) {
return
}
idleTracker := r.Context().Value("idletracker").(*idletracker.IdleTracker)
idleTracker := r.Context().Value("idletracker").(*idle.Tracker)
hijackChan := make(chan bool, 1)
// Perform HTTP attach.
@ -109,7 +109,7 @@ func AttachContainer(w http.ResponseWriter, r *http.Request) {
// We do need to tell the idle tracker that the
// connection has been closed, though. We can guarantee
// that is true after HTTPAttach exits.
idleTracker.TrackHijackedClosed()
idleTracker.Close()
} else {
// A hijack was not successfully completed. We need to
// report the error normally.

6
pkg/api/handlers/compat/exec.go
View File

@ -10,7 +10,7 @@ import (
"github.com/containers/podman/v2/libpod/define"
"github.com/containers/podman/v2/pkg/api/handlers"
"github.com/containers/podman/v2/pkg/api/handlers/utils"
"github.com/containers/podman/v2/pkg/api/server/idletracker"
"github.com/containers/podman/v2/pkg/api/server/idle"
"github.com/containers/podman/v2/pkg/specgen/generate"
"github.com/gorilla/mux"
"github.com/pkg/errors"
@ -174,7 +174,7 @@ func ExecStartHandler(w http.ResponseWriter, r *http.Request) {
return
}
idleTracker := r.Context().Value("idletracker").(*idletracker.IdleTracker)
idleTracker := r.Context().Value("idletracker").(*idle.Tracker)
hijackChan := make(chan bool, 1)
if err := sessionCtr.ExecHTTPStartAndAttach(sessionID, r, w, nil, nil, nil, hijackChan); err != nil {
@ -186,7 +186,7 @@ func ExecStartHandler(w http.ResponseWriter, r *http.Request) {
// We do need to tell the idle tracker that the
// connection has been closed, though. We can guarantee
// that is true after HTTPAttach exits.
idleTracker.TrackHijackedClosed()
idleTracker.Close()
} else {
// A hijack was not successfully completed. We need to
// report the error normally.

96
pkg/api/server/idle/tracker.go Normal file
View File

@ -0,0 +1,96 @@
package idle
import (
"net"
"net/http"
"sync"
"time"
"github.com/sirupsen/logrus"
)
// Tracker holds the state for the server's idle tracking
type Tracker struct {
// Duration is the API idle window
Duration time.Duration
hijacked int // count of active connections managed by handlers
managed map[net.Conn]struct{} // set of active connections managed by http package
mux sync.Mutex // protect managed map
timer *time.Timer
total int // total number of connections made to this server instance
}
// NewTracker creates and initializes a new Tracker object
// For best behavior, duration should be 2x http idle connection timeout
func NewTracker(idle time.Duration) *Tracker {
return &Tracker{
managed: make(map[net.Conn]struct{}),
Duration: idle,
timer: time.NewTimer(idle),
}
}
// ConnState is called on HTTP connection state changes.
// - Once StateHijacked, StateClose is _NOT_ called on that connection
// - There are two "idle" timeouts, the http idle connection (not to be confused with the TCP/IP idle socket timeout)
// and the API idle window. The caller should set the http idle timeout to 2x the time provided to NewTacker() which
// is the API idle window.
func (t *Tracker) ConnState(conn net.Conn, state http.ConnState) {
t.mux.Lock()
defer t.mux.Unlock()
logrus.Debugf("IdleTracker %p:%v %dm+%dh/%dt connection(s)", conn, state, len(t.managed), t.hijacked, t.TotalConnections())
switch state {
case http.StateNew, http.StateActive:
// stop the API timer when the server transitions any connection to an "active" state
t.managed[conn] = struct{}{}
t.timer.Stop()
t.total++
case http.StateHijacked:
// hijacked connections should call Close() when finished.
// Note: If a handler hijack's a connection and then doesn't Close() it,
// the API timer will not fire and the server will _NOT_ timeout.
delete(t.managed, conn)
t.hijacked++
case http.StateIdle:
// When any connection goes into the http idle state, we know:
// - we have an active connection
// - the API timer should not be counting down (See case StateNew/StateActive)
break
case http.StateClosed:
oldActive := t.ActiveConnections()
// Either the server or a hijacking handler has closed the http connection to a client
if _, found := t.managed[conn]; found {
delete(t.managed, conn)
} else {
t.hijacked-- // guarded by t.mux above
}
// Transitioned from any "active" connection to no connections
if oldActive > 0 && t.ActiveConnections() == 0 {
t.timer.Stop() // See library source for Reset() issues and why they are not fixed
t.timer.Reset(t.Duration) // Restart the API window timer
}
}
}
// Close is used to update Tracker that a StateHijacked connection has been closed by handler (StateClosed)
func (t *Tracker) Close() {
t.ConnState(nil, http.StateClosed)
}
// ActiveConnections returns the number of current managed or StateHijacked connections
func (t *Tracker) ActiveConnections() int {
return len(t.managed) + t.hijacked
}
// TotalConnections returns total number of connections made to this instance of the service
func (t *Tracker) TotalConnections() int {
return t.total
}
// Done is called when idle timer has expired
func (t *Tracker) Done() <-chan time.Time {
return t.timer.C
}

74
pkg/api/server/idletracker/idletracker.go
View File

@ -1,74 +0,0 @@
package idletracker
import (
"net"
"net/http"
"sync"
"time"
"github.com/sirupsen/logrus"
)
type IdleTracker struct {
http map[net.Conn]struct{}
hijacked int
total int
mux sync.Mutex
timer *time.Timer
Duration time.Duration
}
func NewIdleTracker(idle time.Duration) *IdleTracker {
return &IdleTracker{
http: make(map[net.Conn]struct{}),
Duration: idle,
timer: time.NewTimer(idle),
}
}
func (t *IdleTracker) ConnState(conn net.Conn, state http.ConnState) {
t.mux.Lock()
defer t.mux.Unlock()
oldActive := t.ActiveConnections()
logrus.Debugf("IdleTracker %p:%v %d/%d connection(s)", conn, state, oldActive, t.TotalConnections())
switch state {
case http.StateNew, http.StateActive:
t.http[conn] = struct{}{}
// stop the timer if we transitioned from idle
if oldActive == 0 {
t.timer.Stop()
}
t.total++
case http.StateHijacked:
// hijacked connections are handled elsewhere
delete(t.http, conn)
t.hijacked++
case http.StateIdle, http.StateClosed:
delete(t.http, conn)
// Restart the timer if we've become idle
if oldActive > 0 && len(t.http) == 0 {
t.timer.Stop()
t.timer.Reset(t.Duration)
}
}
}
func (t *IdleTracker) TrackHijackedClosed() {
t.mux.Lock()
defer t.mux.Unlock()
t.hijacked--
}
func (t *IdleTracker) ActiveConnections() int {
return len(t.http) + t.hijacked
}
func (t *IdleTracker) TotalConnections() int {
return t.total
}
func (t *IdleTracker) Done() <-chan time.Time {
return t.timer.C
}

22
pkg/api/server/server.go
View File

@ -16,7 +16,7 @@ import (
"github.com/containers/podman/v2/libpod"
"github.com/containers/podman/v2/pkg/api/handlers"
"github.com/containers/podman/v2/pkg/api/server/idletracker"
"github.com/containers/podman/v2/pkg/api/server/idle"
"github.com/coreos/go-systemd/v22/activation"
"github.com/coreos/go-systemd/v22/daemon"
"github.com/gorilla/mux"
@ -26,14 +26,14 @@ import (
)
type APIServer struct {
http.Server // The HTTP work happens here
*schema.Decoder // Decoder for Query parameters to structs
context.Context // Context to carry objects to handlers
*libpod.Runtime // Where the real work happens
net.Listener // mux for routing HTTP API calls to libpod routines
context.CancelFunc // Stop APIServer
idleTracker *idletracker.IdleTracker // Track connections to support idle shutdown
pprof *http.Server // Sidecar http server for providing performance data
http.Server // The HTTP work happens here
*schema.Decoder // Decoder for Query parameters to structs
context.Context // Context to carry objects to handlers
*libpod.Runtime // Where the real work happens
net.Listener // mux for routing HTTP API calls to libpod routines
context.CancelFunc // Stop APIServer
idleTracker *idle.Tracker // Track connections to support idle shutdown
pprof *http.Server // Sidecar http server for providing performance data
}
// Number of seconds to wait for next request, if exceeded shutdown server
@ -70,13 +70,13 @@ func newServer(runtime *libpod.Runtime, duration time.Duration, listener *net.Li
}
router := mux.NewRouter().UseEncodedPath()
idle := idletracker.NewIdleTracker(duration)
idle := idle.NewTracker(duration)
server := APIServer{
Server: http.Server{
Handler: router,
ReadHeaderTimeout: 20 * time.Second,
IdleTimeout: duration,
IdleTimeout: duration * 2,
ConnState: idle.ConnState,
ErrorLog: log.New(logrus.StandardLogger().Out, "", 0),
},