luxolus/open-consul
2
0
Fork 0
Code Issues 1 Pull requests Packages Releases Wiki Activity

Merge pull request #2394 from adamwg/reap-the-reaper

Browse source 
Remove the child process reaper (resolve #1988)
This commit is contained in:
James Phillips 2016-10-06 21:35:03 -07:00 committed by GitHub
parent 69eb0f75e5 fa08665ad2
commit 9a36cd4bbf
11 changed files with 4 additions and 591 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

9
command/agent/agent.go
View file

@ -116,14 +116,6 @@ type Agent struct {
// agent methods use this, so use with care and never override
// outside of a unit test.
endpoints map[string]string
// reapLock is used to prevent child process reaping from interfering
// with normal waiting for subprocesses to complete. Any time you exec
// and wait, you should take a read lock on this mutex. Only the reaper
// takes the write lock. This setup prevents us from serializing all the
// child process management with each other, it just serializes them
// with the child process reaper.
reapLock sync.RWMutex
}
// Create is used to create a new Agent. Returns
@ -1042,7 +1034,6 @@ func (a *Agent) AddCheck(check *structs.HealthCheck, chkType *CheckType, persist
Interval: chkType.Interval,
Timeout: chkType.Timeout,
Logger: a.logger,
ReapLock: &a.reapLock,
}
monitor.Start()
a.checkMonitors[check.CheckID] = monitor

32
command/agent/command.go
View file

@ -20,7 +20,6 @@ import (
"github.com/hashicorp/consul/lib"
"github.com/hashicorp/consul/watch"
"github.com/hashicorp/go-checkpoint"
"github.com/hashicorp/go-reap"
"github.com/hashicorp/go-syslog"
"github.com/hashicorp/logutils"
scada "github.com/hashicorp/scada-client/scada"
@ -771,33 +770,6 @@ func (c *Command) Run(args []string) int {
defer server.Shutdown()
}
// Enable child process reaping
if (config.Reap != nil && *config.Reap) || (config.Reap == nil && os.Getpid() == 1) {
if !reap.IsSupported() {
c.Ui.Error("Child process reaping is not supported on this platform (set reap=false)")
return 1
} else {
logger := c.agent.logger
logger.Printf("[DEBUG] Automatically reaping child processes")
pids := make(reap.PidCh, 1)
errors := make(reap.ErrorCh, 1)
go func() {
for {
select {
case pid := <-pids:
logger.Printf("[DEBUG] Reaped child process %d", pid)
case err := <-errors:
logger.Printf("[ERR] Error reaping child process: %v", err)
case <-c.agent.shutdownCh:
return
}
}
}()
go reap.ReapChildren(pids, errors, c.agent.shutdownCh, &c.agent.reapLock)
}
}
// Check and shut down the SCADA listeners at the end
defer func() {
if c.scadaHttp != nil {
@ -829,7 +801,7 @@ func (c *Command) Run(args []string) int {
// Register the watches
for _, wp := range config.WatchPlans {
go func(wp *watch.WatchPlan) {
wp.Handler = makeWatchHandler(logOutput, wp.Exempt["handler"], &c.agent.reapLock)
wp.Handler = makeWatchHandler(logOutput, wp.Exempt["handler"])
wp.LogOutput = c.logOutput
if err := wp.Run(httpAddr.String()); err != nil {
c.Ui.Error(fmt.Sprintf("Error running watch: %v", err))
@ -1017,7 +989,7 @@ func (c *Command) handleReload(config *Config) *Config {
// Register the new watches
for _, wp := range newConf.WatchPlans {
go func(wp *watch.WatchPlan) {
wp.Handler = makeWatchHandler(c.logOutput, wp.Exempt["handler"], &c.agent.reapLock)
wp.Handler = makeWatchHandler(c.logOutput, wp.Exempt["handler"])
wp.LogOutput = c.logOutput
if err := wp.Run(httpAddr.String()); err != nil {
c.Ui.Error(fmt.Sprintf("Error running watch: %v", err))

6
command/agent/remote_exec.go
View file

@ -135,12 +135,6 @@ func (a *Agent) handleRemoteExec(msg *UserEvent) {
return
}
// Disable child process reaping so that we can get this command's
// return value. Note that we take the read lock here since we are
// waiting on a specific PID and don't need to serialize all waits.
a.reapLock.RLock()
defer a.reapLock.RUnlock()
// Ensure we write out an exit code
exitCode := 0
defer a.remoteExecWriteExitCode(&event, &exitCode)

9
command/agent/watch_handler.go
View file

@ -8,7 +8,6 @@ import (
"log"
"os"
"strconv"
"sync"
"github.com/armon/circbuf"
"github.com/hashicorp/consul/watch"
@ -34,16 +33,10 @@ func verifyWatchHandler(params interface{}) error {
}
// makeWatchHandler returns a handler for the given watch
func makeWatchHandler(logOutput io.Writer, params interface{}, reapLock *sync.RWMutex) watch.HandlerFunc {
func makeWatchHandler(logOutput io.Writer, params interface{}) watch.HandlerFunc {
script := params.(string)
logger := log.New(logOutput, "", log.LstdFlags)
fn := func(idx uint64, data interface{}) {
// Disable child process reaping so that we can get this command's
// return value. Note that we take the read lock here since we are
// waiting on a specific PID and don't need to serialize all waits.
reapLock.RLock()
defer reapLock.RUnlock()
// Create the command
cmd, err := ExecScript(script)
if err != nil {

3
command/agent/watch_handler_test.go
View file

@ -3,7 +3,6 @@ package agent
import (
"io/ioutil"
"os"
"sync"
"testing"
)
@ -26,7 +25,7 @@ func TestMakeWatchHandler(t *testing.T) {
defer os.Remove("handler_out")
defer os.Remove("handler_index_out")
script := "echo $CONSUL_INDEX >> handler_index_out && cat >> handler_out"
handler := makeWatchHandler(os.Stderr, script, &sync.RWMutex{})
handler := makeWatchHandler(os.Stderr, script)
handler(100, []string{"foo", "bar", "baz"})
raw, err := ioutil.ReadFile("handler_out")
if err != nil {

363
vendor/github.com/hashicorp/go-reap/LICENSE generated vendored
View file

@ -1,363 +0,0 @@
Mozilla Public License, version 2.0
1. Definitions
1.1. "Contributor"
means each individual or legal entity that creates, contributes to the
creation of, or owns Covered Software.
1.2. "Contributor Version"
means the combination of the Contributions of others (if any) used by a
Contributor and that particular Contributor's Contribution.
1.3. "Contribution"
means Covered Software of a particular Contributor.
1.4. "Covered Software"
means Source Code Form to which the initial Contributor has attached the
notice in Exhibit A, the Executable Form of such Source Code Form, and
Modifications of such Source Code Form, in each case including portions
thereof.
1.5. "Incompatible With Secondary Licenses"
means
a. that the initial Contributor has attached the notice described in
Exhibit B to the Covered Software; or
b. that the Covered Software was made available under the terms of
version 1.1 or earlier of the License, but not also under the terms of
a Secondary License.
1.6. "Executable Form"
means any form of the work other than Source Code Form.
1.7. "Larger Work"
means a work that combines Covered Software with other material, in a
separate file or files, that is not Covered Software.
1.8. "License"
means this document.
1.9. "Licensable"
means having the right to grant, to the maximum extent possible, whether
at the time of the initial grant or subsequently, any and all of the
rights conveyed by this License.
1.10. "Modifications"
means any of the following:
a. any file in Source Code Form that results from an addition to,
deletion from, or modification of the contents of Covered Software; or
b. any new file in Source Code Form that contains any Covered Software.
1.11. "Patent Claims" of a Contributor
means any patent claim(s), including without limitation, method,
process, and apparatus claims, in any patent Licensable by such
Contributor that would be infringed, but for the grant of the License,
by the making, using, selling, offering for sale, having made, import,
or transfer of either its Contributions or its Contributor Version.
1.12. "Secondary License"
means either the GNU General Public License, Version 2.0, the GNU Lesser
General Public License, Version 2.1, the GNU Affero General Public
License, Version 3.0, or any later versions of those licenses.
1.13. "Source Code Form"
means the form of the work preferred for making modifications.
1.14. "You" (or "Your")
means an individual or a legal entity exercising rights under this
License. For legal entities, "You" includes any entity that controls, is
controlled by, or is under common control with You. For purposes of this
definition, "control" means (a) the power, direct or indirect, to cause
the direction or management of such entity, whether by contract or
otherwise, or (b) ownership of more than fifty percent (50%) of the
outstanding shares or beneficial ownership of such entity.
2. License Grants and Conditions
2.1. Grants
Each Contributor hereby grants You a world-wide, royalty-free,
non-exclusive license:
a. under intellectual property rights (other than patent or trademark)
Licensable by such Contributor to use, reproduce, make available,
modify, display, perform, distribute, and otherwise exploit its
Contributions, either on an unmodified basis, with Modifications, or
as part of a Larger Work; and
b. under Patent Claims of such Contributor to make, use, sell, offer for
sale, have made, import, and otherwise transfer either its
Contributions or its Contributor Version.
2.2. Effective Date
The licenses granted in Section 2.1 with respect to any Contribution
become effective for each Contribution on the date the Contributor first
distributes such Contribution.
2.3. Limitations on Grant Scope
The licenses granted in this Section 2 are the only rights granted under
this License. No additional rights or licenses will be implied from the
distribution or licensing of Covered Software under this License.
Notwithstanding Section 2.1(b) above, no patent license is granted by a
Contributor:
a. for any code that a Contributor has removed from Covered Software; or
b. for infringements caused by: (i) Your and any other third party's
modifications of Covered Software, or (ii) the combination of its
Contributions with other software (except as part of its Contributor
Version); or
c. under Patent Claims infringed by Covered Software in the absence of
its Contributions.
This License does not grant any rights in the trademarks, service marks,
or logos of any Contributor (except as may be necessary to comply with
the notice requirements in Section 3.4).
2.4. Subsequent Licenses
No Contributor makes additional grants as a result of Your choice to
distribute the Covered Software under a subsequent version of this
License (see Section 10.2) or under the terms of a Secondary License (if
permitted under the terms of Section 3.3).
2.5. Representation
Each Contributor represents that the Contributor believes its
Contributions are its original creation(s) or it has sufficient rights to
grant the rights to its Contributions conveyed by this License.
2.6. Fair Use
This License is not intended to limit any rights You have under
applicable copyright doctrines of fair use, fair dealing, or other
equivalents.
2.7. Conditions
Sections 3.1, 3.2, 3.3, and 3.4 are conditions of the licenses granted in
Section 2.1.
3. Responsibilities
3.1. Distribution of Source Form
All distribution of Covered Software in Source Code Form, including any
Modifications that You create or to which You contribute, must be under
the terms of this License. You must inform recipients that the Source
Code Form of the Covered Software is governed by the terms of this
License, and how they can obtain a copy of this License. You may not
attempt to alter or restrict the recipients' rights in the Source Code
Form.
3.2. Distribution of Executable Form
If You distribute Covered Software in Executable Form then:
a. such Covered Software must also be made available in Source Code Form,
as described in Section 3.1, and You must inform recipients of the
Executable Form how they can obtain a copy of such Source Code Form by
reasonable means in a timely manner, at a charge no more than the cost
of distribution to the recipient; and
b. You may distribute such Executable Form under the terms of this
License, or sublicense it under different terms, provided that the
license for the Executable Form does not attempt to limit or alter the
recipients' rights in the Source Code Form under this License.
3.3. Distribution of a Larger Work
You may create and distribute a Larger Work under terms of Your choice,
provided that You also comply with the requirements of this License for
the Covered Software. If the Larger Work is a combination of Covered
Software with a work governed by one or more Secondary Licenses, and the
Covered Software is not Incompatible With Secondary Licenses, this
License permits You to additionally distribute such Covered Software
under the terms of such Secondary License(s), so that the recipient of
the Larger Work may, at their option, further distribute the Covered
Software under the terms of either this License or such Secondary
License(s).
3.4. Notices
You may not remove or alter the substance of any license notices
(including copyright notices, patent notices, disclaimers of warranty, or
limitations of liability) contained within the Source Code Form of the
Covered Software, except that You may alter any license notices to the
extent required to remedy known factual inaccuracies.
3.5. Application of Additional Terms
You may choose to offer, and to charge a fee for, warranty, support,
indemnity or liability obligations to one or more recipients of Covered
Software. However, You may do so only on Your own behalf, and not on
behalf of any Contributor. You must make it absolutely clear that any
such warranty, support, indemnity, or liability obligation is offered by
You alone, and You hereby agree to indemnify every Contributor for any
liability incurred by such Contributor as a result of warranty, support,
indemnity or liability terms You offer. You may include additional
disclaimers of warranty and limitations of liability specific to any
jurisdiction.
4. Inability to Comply Due to Statute or Regulation
If it is impossible for You to comply with any of the terms of this License
with respect to some or all of the Covered Software due to statute,
judicial order, or regulation then You must: (a) comply with the terms of
this License to the maximum extent possible; and (b) describe the
limitations and the code they affect. Such description must be placed in a
text file included with all distributions of the Covered Software under
this License. Except to the extent prohibited by statute or regulation,
such description must be sufficiently detailed for a recipient of ordinary
skill to be able to understand it.
5. Termination
5.1. The rights granted under this License will terminate automatically if You
fail to comply with any of its terms. However, if You become compliant,
then the rights granted under this License from a particular Contributor
are reinstated (a) provisionally, unless and until such Contributor
explicitly and finally terminates Your grants, and (b) on an ongoing
basis, if such Contributor fails to notify You of the non-compliance by
some reasonable means prior to 60 days after You have come back into
compliance. Moreover, Your grants from a particular Contributor are
reinstated on an ongoing basis if such Contributor notifies You of the
non-compliance by some reasonable means, this is the first time You have
received notice of non-compliance with this License from such
Contributor, and You become compliant prior to 30 days after Your receipt
of the notice.
5.2. If You initiate litigation against any entity by asserting a patent
infringement claim (excluding declaratory judgment actions,
counter-claims, and cross-claims) alleging that a Contributor Version
directly or indirectly infringes any patent, then the rights granted to
You by any and all Contributors for the Covered Software under Section
2.1 of this License shall terminate.
5.3. In the event of termination under Sections 5.1 or 5.2 above, all end user
license agreements (excluding distributors and resellers) which have been
validly granted by You or Your distributors under this License prior to
termination shall survive termination.
6. Disclaimer of Warranty
Covered Software is provided under this License on an "as is" basis,
without warranty of any kind, either expressed, implied, or statutory,
including, without limitation, warranties that the Covered Software is free
of defects, merchantable, fit for a particular purpose or non-infringing.
The entire risk as to the quality and performance of the Covered Software
is with You. Should any Covered Software prove defective in any respect,
You (not any Contributor) assume the cost of any necessary servicing,
repair, or correction. This disclaimer of warranty constitutes an essential
part of this License. No use of any Covered Software is authorized under
this License except under this disclaimer.
7. Limitation of Liability
Under no circumstances and under no legal theory, whether tort (including
negligence), contract, or otherwise, shall any Contributor, or anyone who
distributes Covered Software as permitted above, be liable to You for any
direct, indirect, special, incidental, or consequential damages of any
character including, without limitation, damages for lost profits, loss of
goodwill, work stoppage, computer failure or malfunction, or any and all
other commercial damages or losses, even if such party shall have been
informed of the possibility of such damages. This limitation of liability
shall not apply to liability for death or personal injury resulting from
such party's negligence to the extent applicable law prohibits such
limitation. Some jurisdictions do not allow the exclusion or limitation of
incidental or consequential damages, so this exclusion and limitation may
not apply to You.
8. Litigation
Any litigation relating to this License may be brought only in the courts
of a jurisdiction where the defendant maintains its principal place of
business and such litigation shall be governed by laws of that
jurisdiction, without reference to its conflict-of-law provisions. Nothing
in this Section shall prevent a party's ability to bring cross-claims or
counter-claims.
9. Miscellaneous
This License represents the complete agreement concerning the subject
matter hereof. If any provision of this License is held to be
unenforceable, such provision shall be reformed only to the extent
necessary to make it enforceable. Any law or regulation which provides that
the language of a contract shall be construed against the drafter shall not
be used to construe this License against a Contributor.
10. Versions of the License
10.1. New Versions
Mozilla Foundation is the license steward. Except as provided in Section
10.3, no one other than the license steward has the right to modify or
publish new versions of this License. Each version will be given a
distinguishing version number.
10.2. Effect of New Versions
You may distribute the Covered Software under the terms of the version
of the License under which You originally received the Covered Software,
or under the terms of any subsequent version published by the license
steward.
10.3. Modified Versions
If you create software not governed by this License, and you want to
create a new license for such software, you may create and use a
modified version of this License if you rename the license and remove
any references to the name of the license steward (except to note that
such modified license differs from this License).
10.4. Distributing Source Code Form that is Incompatible With Secondary
Licenses If You choose to distribute Source Code Form that is
Incompatible With Secondary Licenses under the terms of this version of
the License, the notice described in Exhibit B of this License must be
attached.
Exhibit A - Source Code Form License Notice
This Source Code Form is subject to the
terms of the Mozilla Public License, v.
2.0. If a copy of the MPL was not
distributed with this file, You can
obtain one at
http://mozilla.org/MPL/2.0/.
If it is not possible or desirable to put the notice in a particular file,
then You may include the notice in a location (such as a LICENSE file in a
relevant directory) where a recipient would be likely to look for such a
notice.
You may add additional accurate notices of copyright ownership.
Exhibit B - "Incompatible With Secondary Licenses" Notice
This Source Code Form is "Incompatible
With Secondary Licenses", as defined by
the Mozilla Public License, v. 2.0.

46
vendor/github.com/hashicorp/go-reap/README.md generated vendored
View file

@ -1,46 +0,0 @@
# go-reap
Provides a super simple set of functions for reaping child processes. This is
useful for running applications as PID 1 in a Docker container.
Note that a mutex is supplied to allow your application to prevent reaping of
child processes during certain periods. You need to use care in order to
prevent the reaper from stealing your return values from uses of packages like
Go's exec. We use an `RWMutex` so that we don't serialize all of your
application's execution of sub processes with each other, but we do serialize
them with reaping. Your application should get a read lock when it wants to do
a wait and be safe from the reaper.
This should be supported on most UNIX flavors, but is not supported on Windows
or Solaris. Unsupported platforms have a stub implementation that's safe to call,
as well as an API to check if reaping is supported so that you can produce an
error in your application code.
Documentation
=============
The full documentation is available on [Godoc](http://godoc.org/github.com/hashicorp/go-reap).
Example
=======
Below is a simple example of usage
```go
// Reap children with no control or feedback.
go ReapChildren(nil, nil, nil)
// Get feedback on reaped children and errors.
if reap.IsSupported() {
pids := make(reap.PidCh, 1)
errors := make(reap.ErrorCh, 1)
done := make(chan struct{})
var reapLock sync.RWMutex
go ReapChildren(pids, errors, done, &reapLock)
// ...
close(done)
} else {
fmt.Println("Sorry, go-reap isn't supported on your platform.")
}
```

8
vendor/github.com/hashicorp/go-reap/reap.go generated vendored
View file

@ -1,8 +0,0 @@
package reap
// ErrorCh is an error channel that lets you know when an error was
// encountered while reaping child processes.
type ErrorCh chan error
// PidCh returns the process IDs of reaped child processes.
type PidCh chan int

17
vendor/github.com/hashicorp/go-reap/reap_stub.go generated vendored
View file

@ -1,17 +0,0 @@
// +build windows solaris
package reap
import (
"sync"
)
// IsSupported returns true if child process reaping is supported on this
// platform. This version always returns false.
func IsSupported() bool {
return false
}
// ReapChildren is not supported so this always returns right away.
func ReapChildren(pids PidCh, errors ErrorCh, done chan struct{}, reapLock *sync.RWMutex) {
}

96
vendor/github.com/hashicorp/go-reap/reap_unix.go generated vendored
View file

@ -1,96 +0,0 @@
// +build !windows,!solaris
package reap
import (
"os"
"os/signal"
"sync"
"golang.org/x/sys/unix"
)
// IsSupported returns true if child process reaping is supported on this
// platform.
func IsSupported() bool {
return true
}
// ReapChildren is a long-running routine that blocks waiting for child
// processes to exit and reaps them, reporting reaped process IDs to the
// optional pids channel and any errors to the optional errors channel.
//
// The optional reapLock will be used to prevent reaping during periods
// when you know your application is waiting for subprocesses to return.
// You need to use care in order to prevent the reaper from stealing your
// return values from uses of packages like Go's exec. We use an RWMutex
// so that we don't serialize all of the application's execution of sub
// processes with each other, but we do serialize them with reaping. The
// application should get a read lock when it wants to do a wait.
func ReapChildren(pids PidCh, errors ErrorCh, done chan struct{}, reapLock *sync.RWMutex) {
c := make(chan os.Signal, 1)
signal.Notify(c, unix.SIGCHLD)
for {
// Block for an incoming signal that a child has exited.
select {
case <-c:
// Got a child signal, drop out and reap.
case <-done:
return
}
// Attempt to reap all abandoned child processes after getting
// the reap lock, which makes sure the application isn't doing
// any waiting of its own. Note that we do the full write lock
// here.
func() {
if reapLock != nil {
reapLock.Lock()
defer reapLock.Unlock()
}
POLL:
// Try to reap children until there aren't any more. We
// never block in here so that we are always responsive
// to signals, at the expense of possibly leaving a
// child behind if we get here too quickly. Any
// stragglers should get reaped the next time we see a
// signal, so we won't leak in the long run.
var status unix.WaitStatus
pid, err := unix.Wait4(-1, &status, unix.WNOHANG, nil)
switch err {
case nil:
// Got a child, clean this up and poll again.
if pid > 0 {
if pids != nil {
pids <- pid
}
goto POLL
}
return
case unix.ECHILD:
// No more children, we are done.
return
case unix.EINTR:
// We got interrupted, try again. This likely
// can't happen since we are calling Wait4 in a
// non-blocking fashion, but it's good to be
// complete and handle this case rather than
// fail.
goto POLL
default:
// We got some other error we didn't expect.
// Wait for another SIGCHLD so we don't
// potentially spam in here and chew up CPU.
if errors != nil {
errors <- err
}
return
}
}()
}
}

6
vendor/vendor.json vendored
View file

@ -235,12 +235,6 @@
"revision": "d30f09973e19c1dfcd120b2d9c4f168e68d6b5d5",
"revisionTime": "2015-09-16T20:57:42Z"
},
{
"checksumSHA1": "7qEpaAJA78EvQDs16x9mYOWfgqo=",
"path": "github.com/hashicorp/go-reap",
"revision": "2d85522212dcf5a84c6b357094f5c44710441912",
"revisionTime": "2016-01-13T17:25:55Z"
},
{
"checksumSHA1": "bfVGm7xZ2VFpddJp3KEPUZ8Y9Po=",
"path": "github.com/hashicorp/go-retryablehttp",