Release 2021.5.0

to help understand why the ingress rule logged is being selected.

in addition, combine "Request Headers..." and "Serving with ingress..." logs
into this updated log.

Co-authored-by: Silver <sssilver@users.noreply.github.com>

CHANGES.md

@@ -1,5 +1,17 @@
 **Experimental**: This is a new format for release notes. The format and availability is subject to change.
 
+## 2020.5.0
+
+### New Features
+- It is now possible to run the same tunnel using more than one `cloudflared` instance. This is a server-side change and
+  is compatible with any client version that uses Named Tunnels.
+
+  To get started, visit our [developer documentation](https://developers.cloudflare.com/cloudflare-one/connections/connect-apps/run-tunnel/deploy-cloudflared-replicas).
+- `cloudflared tunnel ingress validate` will now warn about unused keys in your config file. This is helpful for
+  detecting typos in your config.
+- If `cloudflared` detects it is running inside a Linux container, it will limit itself to use only the number of CPUs
+  the pod has been granted, instead of trying to use every CPU available.
+
 ## 2021.4.0
 
 ### Bug Fixes
@@ -129,4 +141,3 @@ ingress:
 
 - The maximum number of upstream connections is now limited by default which should fix reported issues of cloudflared
   exhausting CPU usage when faced with connectivity issues.
-

Dockerfile

@@ -1,7 +1,7 @@
 # use a builder image for building cloudflare
 ARG TARGET_GOOS
 ARG TARGET_GOARCH
-FROM golang:1.15.7 as builder
+FROM golang:1.16.4 as builder
 ENV GO111MODULE=on \
     CGO_ENABLED=0 \
     TARGET_GOOS=${TARGET_GOOS} \

RELEASE_NOTES

@@ -1,3 +1,17 @@
+2021.5.0
+- 2021-05-10 TUN-4384: Silence log from automaxprocs
+- 2021-05-10 AUTH-3537: AUDs in JWTs are now always arrays
+- 2021-05-10 Update changelog for 2021.5.0
+- 2021-05-03 TUN-4343: Fix broken build by setting debug field correctly
+- 2021-05-06 TUN-4356: Set AUTOMAXPROCS to the CPU limit when running in a Linux container
+- 2021-05-06 TUN-4357: Bump Go to 1.16
+- 2021-05-06 TUN-4359: Warn about unused keys in 'tunnel ingress validate'
+- 2021-04-30 debug: log host / path
+- 2021-04-20 AUTH-3513: Checks header for app info in case response is a 403/401 from the edge
+- 2021-04-29 TUN-4000: Release notes for cloudflared replica model
+- 2021-04-09 TUN-2853: rename STDIN-CONTROL env var to STDIN_CONTROL
+- 2021-04-09 TUN-4206: Better error message when user is only using one ingress rule
+
 2021.4.0
 - 2021-04-05 TUN-4178: Fix component test for running as a service in MacOS to not assume a named tunnel
 - 2021-04-05 TUN-4177: Running with proxy-dns should not prevent running Named Tunnels

cfsetup.yaml

@@ -1,4 +1,4 @@
-pinned_go: &pinned_go go=1.15.7-1
+pinned_go: &pinned_go go=1.16.4-3
 pinned_go_fips: &pinned_go_fips go-fips=1.15.5-3
 
 build_dir: &build_dir /cfsetup_build
@@ -279,8 +279,8 @@ centos-7:
       - https://dl.fedoraproject.org/pub/epel/epel-release-latest-7.noarch.rpm
     pre-cache:
       - yum install -y fakeroot
-      - wget https://golang.org/dl/go1.15.7.linux-amd64.tar.gz -P /tmp/
-      - tar -C /usr/local -xzf /tmp/go1.15.7.linux-amd64.tar.gz
+      - wget https://golang.org/dl/go1.16.4.linux-amd64.tar.gz -P /tmp/
+      - tar -C /usr/local -xzf /tmp/go1.16.4.linux-amd64.tar.gz
     post-cache:
       - export PATH=$PATH:/usr/local/go/bin
       - export GOOS=linux
@@ -291,8 +291,8 @@ centos-7:
     builddeps: *el7_builddeps
     pre-cache:
       - yum install -y fakeroot
-      - wget https://golang.org/dl/go1.15.7.linux-amd64.tar.gz -P /tmp/
-      - tar -C /usr/local -xzf /tmp/go1.15.7.linux-amd64.tar.gz
+      - wget https://golang.org/dl/go1.16.4.linux-amd64.tar.gz -P /tmp/
+      - tar -C /usr/local -xzf /tmp/go1.16.4.linux-amd64.tar.gz
     post-cache:
       - export PATH=$PATH:/usr/local/go/bin
       - export GOOS=linux

cmd/cloudflared/cliutil/handler.go

@@ -13,27 +13,38 @@ func Action(actionFunc cli.ActionFunc) cli.ActionFunc {
 }
 
 func ConfiguredAction(actionFunc cli.ActionFunc) cli.ActionFunc {
+	// Adapt actionFunc to the type signature required by ConfiguredActionWithWarnings
+	f := func(context *cli.Context, _ string) error {
+		return actionFunc(context)
+	}
+
+	return ConfiguredActionWithWarnings(f)
+}
+
+// Just like ConfiguredAction, but accepts a second parameter with configuration warnings.
+func ConfiguredActionWithWarnings(actionFunc func(*cli.Context, string) error) cli.ActionFunc {
 	return WithErrorHandler(func(c *cli.Context) error {
-		if err := setFlagsFromConfigFile(c); err != nil {
+		warnings, err := setFlagsFromConfigFile(c)
+		if err != nil {
 			return err
 		}
-		return actionFunc(c)
+		return actionFunc(c, warnings)
 	})
 }
 
-func setFlagsFromConfigFile(c *cli.Context) error {
+func setFlagsFromConfigFile(c *cli.Context) (configWarnings string, err error) {
 	const errorExitCode = 1
 	log := logger.CreateLoggerFromContext(c, logger.EnableTerminalLog)
-	inputSource, err := config.ReadConfigFile(c, log)
+	inputSource, warnings, err := config.ReadConfigFile(c, log)
 	if err != nil {
 		if err == config.ErrNoConfigFile {
-			return nil
+			return "", nil
 		}
-		return cli.Exit(err, errorExitCode)
+		return "", cli.Exit(err, errorExitCode)
 	}
 
 	if err := altsrc.ApplyInputSource(c, inputSource); err != nil {
-		return cli.Exit(err, errorExitCode)
+		return "", cli.Exit(err, errorExitCode)
 	}
-	return nil
+	return warnings, nil
 }

cmd/cloudflared/linux_service.go

@@ -238,7 +238,7 @@ func installLinuxService(c *cli.Context) error {
 			"--origincert", serviceConfigDir + "/" + serviceCredentialFile,
 		}
 	} else {
-		src, err := config.ReadConfigFile(c, log)
+		src, _, err := config.ReadConfigFile(c, log)
 		if err != nil {
 			return err
 		}

cmd/cloudflared/main.go

@@ -10,6 +10,7 @@ import (
 	homedir "github.com/mitchellh/go-homedir"
 	"github.com/pkg/errors"
 	"github.com/urfave/cli/v2"
+	"go.uber.org/automaxprocs/maxprocs"
 
 	"github.com/cloudflare/cloudflared/cmd/cloudflared/access"
 	"github.com/cloudflare/cloudflared/cmd/cloudflared/cliutil"
@@ -47,6 +48,7 @@ func main() {
 	rand.Seed(time.Now().UnixNano())
 	metrics.RegisterBuildInfo(BuildTime, Version)
 	raven.SetRelease(Version)
+	maxprocs.Set()
 
 	// Graceful shutdown channel used by the app. When closed, app must terminate gracefully.
 	// Windows service manager closes this channel when it receives stop command.

cmd/cloudflared/tunnel/cmd.go

@@ -699,7 +699,7 @@ func configureProxyFlags(shouldHide bool) []cli.Flag {
 			Hidden: shouldHide,
 		}),
 		altsrc.NewDurationFlag(&cli.DurationFlag{
-			Name:   ingress.ProxyTCPKeepAlive,
+			Name:   ingress.ProxyTCPKeepAliveFlag,
 			Usage:  "HTTP proxy TCP keepalive duration",
 			Value:  time.Second * 30,
 			Hidden: shouldHide,

cmd/cloudflared/tunnel/ingress_subcommands.go

@@ -45,7 +45,7 @@ func buildIngressSubcommand() *cli.Command {
 func buildValidateIngressCommand() *cli.Command {
 	return &cli.Command{
 		Name:        "validate",
-		Action:      cliutil.ConfiguredAction(validateIngressCommand),
+		Action:      cliutil.ConfiguredActionWithWarnings(validateIngressCommand),
 		Usage:       "Validate the ingress configuration ",
 		UsageText:   "cloudflared tunnel [--config FILEPATH] ingress validate",
 		Description: "Validates the configuration file, ensuring your ingress rules are OK.",
@@ -68,7 +68,7 @@ func buildTestURLCommand() *cli.Command {
 }
 
 // validateIngressCommand check the syntax of the ingress rules in the cloudflared config file
-func validateIngressCommand(c *cli.Context) error {
+func validateIngressCommand(c *cli.Context, warnings string) error {
 	conf := config.GetConfiguration()
 	if conf.Source() == "" {
 		fmt.Println("No configuration file was found. Please create one, or use the --config flag to specify its filepath. You can use the help command to learn more about configuration files")
@@ -81,6 +81,11 @@ func validateIngressCommand(c *cli.Context) error {
 	if c.IsSet("url") {
 		return ingress.ErrURLIncompatibleWithIngress
 	}
+	if warnings != "" {
+		fmt.Println("Warning: unused keys detected in your config file. Here is a list of unused keys:")
+		fmt.Println(warnings)
+		return nil
+	}
 	fmt.Println("OK")
 	return nil
 }

config/configuration.go

@@ -358,13 +358,13 @@ func GetConfiguration() *Configuration {
 // ReadConfigFile returns InputSourceContext initialized from the configuration file.
 // On repeat calls returns with the same file, returns without reading the file again; however,
 // if value of "config" flag changes, will read the new config file
-func ReadConfigFile(c *cli.Context, log *zerolog.Logger) (*configFileSettings, error) {
+func ReadConfigFile(c *cli.Context, log *zerolog.Logger) (settings *configFileSettings, warnings string, err error) {
 	configFile := c.String("config")
 	if configuration.Source() == configFile || configFile == "" {
 		if configuration.Source() == "" {
-			return nil, ErrNoConfigFile
+			return nil, "", ErrNoConfigFile
 		}
-		return &configuration, nil
+		return &configuration, "", nil
 	}
 
 	log.Debug().Msgf("Loading configuration from %s", configFile)
@@ -373,16 +373,27 @@ func ReadConfigFile(c *cli.Context, log *zerolog.Logger) (*configFileSettings, e
 		if os.IsNotExist(err) {
 			err = ErrNoConfigFile
 		}
-		return nil, err
+		return nil, "", err
 	}
 	defer file.Close()
 	if err := yaml.NewDecoder(file).Decode(&configuration); err != nil {
 		if err == io.EOF {
 			log.Error().Msgf("Configuration file %s was empty", configFile)
-			return &configuration, nil
+			return &configuration, "", nil
 		}
-		return nil, errors.Wrap(err, "error parsing YAML in config file at "+configFile)
+		return nil, "", errors.Wrap(err, "error parsing YAML in config file at "+configFile)
 	}
 	configuration.sourceFile = configFile
-	return &configuration, nil
+
+	// Parse it again, with strict mode, to find warnings.
+	if file, err := os.Open(configFile); err == nil {
+		decoder := yaml.NewDecoder(file)
+		decoder.SetStrict(true)
+		var unusedConfig configFileSettings
+		if err := decoder.Decode(&unusedConfig); err != nil {
+			warnings = err.Error()
+		}
+	}
+
+	return &configuration, warnings, nil
 }

dev.Dockerfile

@@ -1,4 +1,4 @@
-FROM golang:1.15.7 as builder
+FROM golang:1.16.4 as builder
 ENV GO111MODULE=on \
     CGO_ENABLED=0
 WORKDIR /go/src/github.com/cloudflare/cloudflared/

go.mod

@@ -43,6 +43,7 @@ require (
 	github.com/russross/blackfriday/v2 v2.1.0 // indirect
 	github.com/stretchr/testify v1.6.0
 	github.com/urfave/cli/v2 v2.2.0
+	go.uber.org/automaxprocs v1.4.0
 	golang.org/x/crypto v0.0.0-20200820211705-5c72a883971a
 	golang.org/x/net v0.0.0-20200904194848-62affa334b73
 	golang.org/x/oauth2 v0.0.0-20200902213428-5d25da1a8d43 // indirect

go.sum

@@ -609,6 +609,8 @@ go.opencensus.io v0.22.4/go.mod h1:yxeiOL68Rb0Xd1ddK5vPZ/oVn4vY4Ynel7k9FzqtOIw=
 go.uber.org/atomic v1.3.2/go.mod h1:gD2HeocX3+yG+ygLZcrzQJaqmWj9AIm7n08wl/qW/PE=
 go.uber.org/atomic v1.5.0/go.mod h1:sABNBOSYdrvTF6hTgEIbc7YasKWGhgEQZyfxyTvoXHQ=
 go.uber.org/atomic v1.6.0/go.mod h1:sABNBOSYdrvTF6hTgEIbc7YasKWGhgEQZyfxyTvoXHQ=
+go.uber.org/automaxprocs v1.4.0 h1:CpDZl6aOlLhReez+8S3eEotD7Jx0Os++lemPlMULQP0=
+go.uber.org/automaxprocs v1.4.0/go.mod h1:/mTEdr7LvHhs0v7mjdxDreTz1OG5zdZGqgOnhWiR/+Q=
 go.uber.org/multierr v1.1.0/go.mod h1:wR5kodmAFQ0UK8QlbwjlSNy0Z68gJhDJUG5sjR94q/0=
 go.uber.org/multierr v1.3.0/go.mod h1:VgVr7evmIr6uPjLBxg28wmKNXyqE9akIJ5XnfpiKl+4=
 go.uber.org/multierr v1.5.0/go.mod h1:FeouvMocqHpRaaGuG9EjoKcStLC43Zu/fmqdUMPcKYU=

ingress/ingress_test.go

@@ -402,7 +402,7 @@ func TestSingleOriginSetsConfig(t *testing.T) {
 	flagSet.Bool("hello-world", true, "")
 	flagSet.Duration(ProxyConnectTimeoutFlag, time.Second, "")
 	flagSet.Duration(ProxyTLSTimeoutFlag, time.Second, "")
-	flagSet.Duration(ProxyTCPKeepAlive, time.Second, "")
+	flagSet.Duration(ProxyTCPKeepAliveFlag, time.Second, "")
 	flagSet.Bool(ProxyNoHappyEyeballsFlag, true, "")
 	flagSet.Int(ProxyKeepAliveConnectionsFlag, 10, "")
 	flagSet.Duration(ProxyKeepAliveTimeoutFlag, time.Second, "")
@@ -423,7 +423,7 @@ func TestSingleOriginSetsConfig(t *testing.T) {
 	require.NoError(t, err)
 	err = cliCtx.Set(ProxyTLSTimeoutFlag, "1s")
 	require.NoError(t, err)
-	err = cliCtx.Set(ProxyTCPKeepAlive, "1s")
+	err = cliCtx.Set(ProxyTCPKeepAliveFlag, "1s")
 	require.NoError(t, err)
 	err = cliCtx.Set(ProxyNoHappyEyeballsFlag, "true")
 	require.NoError(t, err)

ingress/origin_request_config.go

@@ -22,7 +22,7 @@ const (
 	Socks5Flag                    = "socks5"
 	ProxyConnectTimeoutFlag       = "proxy-connect-timeout"
 	ProxyTLSTimeoutFlag           = "proxy-tls-timeout"
-	ProxyTCPKeepAlive             = "proxy-tcp-keepalive"
+	ProxyTCPKeepAliveFlag         = "proxy-tcp-keepalive"
 	ProxyNoHappyEyeballsFlag      = "proxy-no-happy-eyeballs"
 	ProxyKeepAliveConnectionsFlag = "proxy-keepalive-connections"
 	ProxyKeepAliveTimeoutFlag     = "proxy-keepalive-timeout"
@@ -60,7 +60,7 @@ func originRequestFromSingeRule(c *cli.Context) OriginRequestConfig {
 	if flag := ProxyTLSTimeoutFlag; c.IsSet(flag) {
 		tlsTimeout = c.Duration(flag)
 	}
-	if flag := ProxyTCPKeepAlive; c.IsSet(flag) {
+	if flag := ProxyTCPKeepAliveFlag; c.IsSet(flag) {
 		tcpKeepAlive = c.Duration(flag)
 	}
 	if flag := ProxyNoHappyEyeballsFlag; c.IsSet(flag) {

origin/proxy.go

@@ -238,8 +238,13 @@ func (p *proxy) logRequest(r *http.Request, fields logFields) {
 	} else {
 		p.log.Debug().Msgf("All requests should have a CF-RAY header. Please open a support ticket with Cloudflare. %s %s %s ", r.Method, r.URL, r.Proto)
 	}
-	p.log.Debug().Msgf("CF-RAY: %s Request Headers %+v", fields.cfRay, r.Header)
-	p.log.Debug().Msgf("CF-RAY: %s Serving with ingress rule %v", fields.cfRay, fields.rule)
+	p.log.Debug().
+		Str("CF-RAY", fields.cfRay).
+		Str("Header", fmt.Sprintf("%+v", r.Header)).
+		Str("host", r.Host).
+		Str("path", r.URL.Path).
+		Interface("rule", fields.rule).
+		Msg("Inbound request")
 
 	if contentLen := r.ContentLength; contentLen == -1 {
 		p.log.Debug().Msgf("CF-RAY: %s Request Content length unknown", fields.cfRay)

token/token.go

@@ -46,7 +46,7 @@ type signalHandler struct {
 	signals    []os.Signal
 }
 
-type appJWTPayload struct {
+type jwtPayload struct {
 	Aud   []string `json:"aud"`
 	Email string   `json:"email"`
 	Exp   int      `json:"exp"`
@@ -57,17 +57,12 @@ type appJWTPayload struct {
 	Subt  string   `json:"sub"`
 }
 
-type orgJWTPayload struct {
-	appJWTPayload
-	Aud string `json:"aud"`
-}
-
 type transferServiceResponse struct {
 	AppToken string `json:"app_token"`
 	OrgToken string `json:"org_token"`
 }
 
-func (p appJWTPayload) isExpired() bool {
+func (p jwtPayload) isExpired() bool {
 	return int(time.Now().Unix()) > p.Exp
 }
 
@@ -346,7 +341,7 @@ func GetOrgTokenIfExists(authDomain string) (string, error) {
 	if err != nil {
 		return "", err
 	}
-	var payload orgJWTPayload
+	var payload jwtPayload
 	err = json.Unmarshal(token.Payload, &payload)
 	if err != nil {
 		return "", err
@@ -368,7 +363,7 @@ func GetAppTokenIfExists(appInfo *AppInfo) (string, error) {
 	if err != nil {
 		return "", err
 	}
-	var payload appJWTPayload
+	var payload jwtPayload
 	err = json.Unmarshal(token.Payload, &payload)
 	if err != nil {
 		return "", err

vendor/go.uber.org/automaxprocs/LICENSE

@@ -0,0 +1,19 @@
+Copyright (c) 2017 Uber Technologies, Inc.
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in
+all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+THE SOFTWARE.

vendor/go.uber.org/automaxprocs/internal/cgroups/cgroup.go

@@ -0,0 +1,78 @@
+// Copyright (c) 2017 Uber Technologies, Inc.
+//
+// Permission is hereby granted, free of charge, to any person obtaining a copy
+// of this software and associated documentation files (the "Software"), to deal
+// in the Software without restriction, including without limitation the rights
+// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+// copies of the Software, and to permit persons to whom the Software is
+// furnished to do so, subject to the following conditions:
+//
+// The above copyright notice and this permission notice shall be included in
+// all copies or substantial portions of the Software.
+//
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+// THE SOFTWARE.
+
+// +build linux
+
+package cgroups
+
+import (
+	"bufio"
+	"io"
+	"os"
+	"path/filepath"
+	"strconv"
+)
+
+// CGroup represents the data structure for a Linux control group.
+type CGroup struct {
+	path string
+}
+
+// NewCGroup returns a new *CGroup from a given path.
+func NewCGroup(path string) *CGroup {
+	return &CGroup{path: path}
+}
+
+// Path returns the path of the CGroup*.
+func (cg *CGroup) Path() string {
+	return cg.path
+}
+
+// ParamPath returns the path of the given cgroup param under itself.
+func (cg *CGroup) ParamPath(param string) string {
+	return filepath.Join(cg.path, param)
+}
+
+// readFirstLine reads the first line from a cgroup param file.
+func (cg *CGroup) readFirstLine(param string) (string, error) {
+	paramFile, err := os.Open(cg.ParamPath(param))
+	if err != nil {
+		return "", err
+	}
+	defer paramFile.Close()
+
+	scanner := bufio.NewScanner(paramFile)
+	if scanner.Scan() {
+		return scanner.Text(), nil
+	}
+	if err := scanner.Err(); err != nil {
+		return "", err
+	}
+	return "", io.ErrUnexpectedEOF
+}
+
+// readInt parses the first line from a cgroup param file as int.
+func (cg *CGroup) readInt(param string) (int, error) {
+	text, err := cg.readFirstLine(param)
+	if err != nil {
+		return 0, err
+	}
+	return strconv.Atoi(text)
+}

vendor/go.uber.org/automaxprocs/internal/cgroups/cgroups.go

@@ -0,0 +1,117 @@
+// Copyright (c) 2017 Uber Technologies, Inc.
+//
+// Permission is hereby granted, free of charge, to any person obtaining a copy
+// of this software and associated documentation files (the "Software"), to deal
+// in the Software without restriction, including without limitation the rights
+// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+// copies of the Software, and to permit persons to whom the Software is
+// furnished to do so, subject to the following conditions:
+//
+// The above copyright notice and this permission notice shall be included in
+// all copies or substantial portions of the Software.
+//
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+// THE SOFTWARE.
+
+// +build linux
+
+package cgroups
+
+const (
+	// _cgroupFSType is the Linux CGroup file system type used in
+	// `/proc/$PID/mountinfo`.
+	_cgroupFSType = "cgroup"
+	// _cgroupSubsysCPU is the CPU CGroup subsystem.
+	_cgroupSubsysCPU = "cpu"
+	// _cgroupSubsysCPUAcct is the CPU accounting CGroup subsystem.
+	_cgroupSubsysCPUAcct = "cpuacct"
+	// _cgroupSubsysCPUSet is the CPUSet CGroup subsystem.
+	_cgroupSubsysCPUSet = "cpuset"
+	// _cgroupSubsysMemory is the Memory CGroup subsystem.
+	_cgroupSubsysMemory = "memory"
+
+	// _cgroupCPUCFSQuotaUsParam is the file name for the CGroup CFS quota
+	// parameter.
+	_cgroupCPUCFSQuotaUsParam = "cpu.cfs_quota_us"
+	// _cgroupCPUCFSPeriodUsParam is the file name for the CGroup CFS period
+	// parameter.
+	_cgroupCPUCFSPeriodUsParam = "cpu.cfs_period_us"
+)
+
+const (
+	_procPathCGroup    = "/proc/self/cgroup"
+	_procPathMountInfo = "/proc/self/mountinfo"
+)
+
+// CGroups is a map that associates each CGroup with its subsystem name.
+type CGroups map[string]*CGroup
+
+// NewCGroups returns a new *CGroups from given `mountinfo` and `cgroup` files
+// under for some process under `/proc` file system (see also proc(5) for more
+// information).
+func NewCGroups(procPathMountInfo, procPathCGroup string) (CGroups, error) {
+	cgroupSubsystems, err := parseCGroupSubsystems(procPathCGroup)
+	if err != nil {
+		return nil, err
+	}
+
+	cgroups := make(CGroups)
+	newMountPoint := func(mp *MountPoint) error {
+		if mp.FSType != _cgroupFSType {
+			return nil
+		}
+
+		for _, opt := range mp.SuperOptions {
+			subsys, exists := cgroupSubsystems[opt]
+			if !exists {
+				continue
+			}
+
+			cgroupPath, err := mp.Translate(subsys.Name)
+			if err != nil {
+				return err
+			}
+			cgroups[opt] = NewCGroup(cgroupPath)
+		}
+
+		return nil
+	}
+
+	if err := parseMountInfo(procPathMountInfo, newMountPoint); err != nil {
+		return nil, err
+	}
+	return cgroups, nil
+}
+
+// NewCGroupsForCurrentProcess returns a new *CGroups instance for the current
+// process.
+func NewCGroupsForCurrentProcess() (CGroups, error) {
+	return NewCGroups(_procPathMountInfo, _procPathCGroup)
+}
+
+// CPUQuota returns the CPU quota applied with the CPU cgroup controller.
+// It is a result of `cpu.cfs_quota_us / cpu.cfs_period_us`. If the value of
+// `cpu.cfs_quota_us` was not set (-1), the method returns `(-1, nil)`.
+func (cg CGroups) CPUQuota() (float64, bool, error) {
+	cpuCGroup, exists := cg[_cgroupSubsysCPU]
+	if !exists {
+		return -1, false, nil
+	}
+
+	cfsQuotaUs, err := cpuCGroup.readInt(_cgroupCPUCFSQuotaUsParam)
+	if defined := cfsQuotaUs > 0; err != nil || !defined {
+		return -1, defined, err
+	}
+
+	cfsPeriodUs, err := cpuCGroup.readInt(_cgroupCPUCFSPeriodUsParam)
+	if err != nil {
+		return -1, false, err
+	}
+
+	return float64(cfsQuotaUs) / float64(cfsPeriodUs), true, nil
+}

vendor/go.uber.org/automaxprocs/internal/cgroups/doc.go

@@ -0,0 +1,23 @@
+// Copyright (c) 2017 Uber Technologies, Inc.
+//
+// Permission is hereby granted, free of charge, to any person obtaining a copy
+// of this software and associated documentation files (the "Software"), to deal
+// in the Software without restriction, including without limitation the rights
+// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+// copies of the Software, and to permit persons to whom the Software is
+// furnished to do so, subject to the following conditions:
+//
+// The above copyright notice and this permission notice shall be included in
+// all copies or substantial portions of the Software.
+//
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+// THE SOFTWARE.
+
+// Package cgroups provides utilities to access Linux control group (CGroups)
+// parameters (CPU quota, for example) for a given process.
+package cgroups

vendor/go.uber.org/automaxprocs/internal/cgroups/errors.go

@@ -0,0 +1,51 @@
+// Copyright (c) 2017 Uber Technologies, Inc.
+//
+// Permission is hereby granted, free of charge, to any person obtaining a copy
+// of this software and associated documentation files (the "Software"), to deal
+// in the Software without restriction, including without limitation the rights
+// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+// copies of the Software, and to permit persons to whom the Software is
+// furnished to do so, subject to the following conditions:
+//
+// The above copyright notice and this permission notice shall be included in
+// all copies or substantial portions of the Software.
+//
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+// THE SOFTWARE.
+
+// +build linux
+
+package cgroups
+
+import "fmt"
+
+type cgroupSubsysFormatInvalidError struct {
+	line string
+}
+
+type mountPointFormatInvalidError struct {
+	line string
+}
+
+type pathNotExposedFromMountPointError struct {
+	mountPoint string
+	root       string
+	path       string
+}
+
+func (err cgroupSubsysFormatInvalidError) Error() string {
+	return fmt.Sprintf("invalid format for CGroupSubsys: %q", err.line)
+}
+
+func (err mountPointFormatInvalidError) Error() string {
+	return fmt.Sprintf("invalid format for MountPoint: %q", err.line)
+}
+
+func (err pathNotExposedFromMountPointError) Error() string {
+	return fmt.Sprintf("path %q is not a descendant of mount point root %q and cannot be exposed from %q", err.path, err.root, err.mountPoint)
+}

vendor/go.uber.org/automaxprocs/internal/cgroups/mountpoint.go

@@ -0,0 +1,166 @@
+// Copyright (c) 2017 Uber Technologies, Inc.
+//
+// Permission is hereby granted, free of charge, to any person obtaining a copy
+// of this software and associated documentation files (the "Software"), to deal
+// in the Software without restriction, including without limitation the rights
+// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+// copies of the Software, and to permit persons to whom the Software is
+// furnished to do so, subject to the following conditions:
+//
+// The above copyright notice and this permission notice shall be included in
+// all copies or substantial portions of the Software.
+//
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+// THE SOFTWARE.
+
+// +build linux
+
+package cgroups
+
+import (
+	"bufio"
+	"os"
+	"path/filepath"
+	"strconv"
+	"strings"
+)
+
+const (
+	_mountInfoSep               = " "
+	_mountInfoOptsSep           = ","
+	_mountInfoOptionalFieldsSep = "-"
+)
+
+const (
+	_miFieldIDMountID = iota
+	_miFieldIDParentID
+	_miFieldIDDeviceID
+	_miFieldIDRoot
+	_miFieldIDMountPoint
+	_miFieldIDOptions
+	_miFieldIDOptionalFields
+
+	_miFieldCountFirstHalf
+)
+
+const (
+	_miFieldOffsetFSType = iota
+	_miFieldOffsetMountSource
+	_miFieldOffsetSuperOptions
+
+	_miFieldCountSecondHalf
+)
+
+const _miFieldCountMin = _miFieldCountFirstHalf + _miFieldCountSecondHalf
+
+// MountPoint is the data structure for the mount points in
+// `/proc/$PID/mountinfo`. See also proc(5) for more information.
+type MountPoint struct {
+	MountID        int
+	ParentID       int
+	DeviceID       string
+	Root           string
+	MountPoint     string
+	Options        []string
+	OptionalFields []string
+	FSType         string
+	MountSource    string
+	SuperOptions   []string
+}
+
+// NewMountPointFromLine parses a line read from `/proc/$PID/mountinfo` and
+// returns a new *MountPoint.
+func NewMountPointFromLine(line string) (*MountPoint, error) {
+	fields := strings.Split(line, _mountInfoSep)
+
+	if len(fields) < _miFieldCountMin {
+		return nil, mountPointFormatInvalidError{line}
+	}
+
+	mountID, err := strconv.Atoi(fields[_miFieldIDMountID])
+	if err != nil {
+		return nil, err
+	}
+
+	parentID, err := strconv.Atoi(fields[_miFieldIDParentID])
+	if err != nil {
+		return nil, err
+	}
+
+	for i, field := range fields[_miFieldIDOptionalFields:] {
+		if field == _mountInfoOptionalFieldsSep {
+			fsTypeStart := _miFieldIDOptionalFields + i + 1
+
+			if len(fields) != fsTypeStart+_miFieldCountSecondHalf {
+				return nil, mountPointFormatInvalidError{line}
+			}
+
+			miFieldIDFSType := _miFieldOffsetFSType + fsTypeStart
+			miFieldIDMountSource := _miFieldOffsetMountSource + fsTypeStart
+			miFieldIDSuperOptions := _miFieldOffsetSuperOptions + fsTypeStart
+
+			return &MountPoint{
+				MountID:        mountID,
+				ParentID:       parentID,
+				DeviceID:       fields[_miFieldIDDeviceID],
+				Root:           fields[_miFieldIDRoot],
+				MountPoint:     fields[_miFieldIDMountPoint],
+				Options:        strings.Split(fields[_miFieldIDOptions], _mountInfoOptsSep),
+				OptionalFields: fields[_miFieldIDOptionalFields:(fsTypeStart - 1)],
+				FSType:         fields[miFieldIDFSType],
+				MountSource:    fields[miFieldIDMountSource],
+				SuperOptions:   strings.Split(fields[miFieldIDSuperOptions], _mountInfoOptsSep),
+			}, nil
+		}
+	}
+
+	return nil, mountPointFormatInvalidError{line}
+}
+
+// Translate converts an absolute path inside the *MountPoint's file system to
+// the host file system path in the mount namespace the *MountPoint belongs to.
+func (mp *MountPoint) Translate(absPath string) (string, error) {
+	relPath, err := filepath.Rel(mp.Root, absPath)
+
+	if err != nil {
+		return "", err
+	}
+	if relPath == ".." || strings.HasPrefix(relPath, "../") {
+		return "", pathNotExposedFromMountPointError{
+			mountPoint: mp.MountPoint,
+			root:       mp.Root,
+			path:       absPath,
+		}
+	}
+
+	return filepath.Join(mp.MountPoint, relPath), nil
+}
+
+// parseMountInfo parses procPathMountInfo (usually at `/proc/$PID/mountinfo`)
+// and yields parsed *MountPoint into newMountPoint.
+func parseMountInfo(procPathMountInfo string, newMountPoint func(*MountPoint) error) error {
+	mountInfoFile, err := os.Open(procPathMountInfo)
+	if err != nil {
+		return err
+	}
+	defer mountInfoFile.Close()
+
+	scanner := bufio.NewScanner(mountInfoFile)
+
+	for scanner.Scan() {
+		mountPoint, err := NewMountPointFromLine(scanner.Text())
+		if err != nil {
+			return err
+		}
+		if err := newMountPoint(mountPoint); err != nil {
+			return err
+		}
+	}
+
+	return scanner.Err()
+}

vendor/go.uber.org/automaxprocs/internal/cgroups/subsys.go

@@ -0,0 +1,102 @@
+// Copyright (c) 2017 Uber Technologies, Inc.
+//
+// Permission is hereby granted, free of charge, to any person obtaining a copy
+// of this software and associated documentation files (the "Software"), to deal
+// in the Software without restriction, including without limitation the rights
+// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+// copies of the Software, and to permit persons to whom the Software is
+// furnished to do so, subject to the following conditions:
+//
+// The above copyright notice and this permission notice shall be included in
+// all copies or substantial portions of the Software.
+//
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+// THE SOFTWARE.
+
+// +build linux
+
+package cgroups
+
+import (
+	"bufio"
+	"os"
+	"strconv"
+	"strings"
+)
+
+const (
+	_cgroupSep       = ":"
+	_cgroupSubsysSep = ","
+)
+
+const (
+	_csFieldIDID = iota
+	_csFieldIDSubsystems
+	_csFieldIDName
+	_csFieldCount
+)
+
+// CGroupSubsys represents the data structure for entities in
+// `/proc/$PID/cgroup`. See also proc(5) for more information.
+type CGroupSubsys struct {
+	ID         int
+	Subsystems []string
+	Name       string
+}
+
+// NewCGroupSubsysFromLine returns a new *CGroupSubsys by parsing a string in
+// the format of `/proc/$PID/cgroup`
+func NewCGroupSubsysFromLine(line string) (*CGroupSubsys, error) {
+	fields := strings.SplitN(line, _cgroupSep, _csFieldCount)
+
+	if len(fields) != _csFieldCount {
+		return nil, cgroupSubsysFormatInvalidError{line}
+	}
+
+	id, err := strconv.Atoi(fields[_csFieldIDID])
+	if err != nil {
+		return nil, err
+	}
+
+	cgroup := &CGroupSubsys{
+		ID:         id,
+		Subsystems: strings.Split(fields[_csFieldIDSubsystems], _cgroupSubsysSep),
+		Name:       fields[_csFieldIDName],
+	}
+
+	return cgroup, nil
+}
+
+// parseCGroupSubsystems parses procPathCGroup (usually at `/proc/$PID/cgroup`)
+// and returns a new map[string]*CGroupSubsys.
+func parseCGroupSubsystems(procPathCGroup string) (map[string]*CGroupSubsys, error) {
+	cgroupFile, err := os.Open(procPathCGroup)
+	if err != nil {
+		return nil, err
+	}
+	defer cgroupFile.Close()
+
+	scanner := bufio.NewScanner(cgroupFile)
+	subsystems := make(map[string]*CGroupSubsys)
+
+	for scanner.Scan() {
+		cgroup, err := NewCGroupSubsysFromLine(scanner.Text())
+		if err != nil {
+			return nil, err
+		}
+		for _, subsys := range cgroup.Subsystems {
+			subsystems[subsys] = cgroup
+		}
+	}
+
+	if err := scanner.Err(); err != nil {
+		return nil, err
+	}
+
+	return subsystems, nil
+}

vendor/go.uber.org/automaxprocs/internal/runtime/cpu_quota_linux.go

@@ -0,0 +1,49 @@
+// Copyright (c) 2017 Uber Technologies, Inc.
+//
+// Permission is hereby granted, free of charge, to any person obtaining a copy
+// of this software and associated documentation files (the "Software"), to deal
+// in the Software without restriction, including without limitation the rights
+// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+// copies of the Software, and to permit persons to whom the Software is
+// furnished to do so, subject to the following conditions:
+//
+// The above copyright notice and this permission notice shall be included in
+// all copies or substantial portions of the Software.
+//
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+// THE SOFTWARE.
+
+// +build linux
+
+package runtime
+
+import (
+	"math"
+
+	cg "go.uber.org/automaxprocs/internal/cgroups"
+)
+
+// CPUQuotaToGOMAXPROCS converts the CPU quota applied to the calling process
+// to a valid GOMAXPROCS value.
+func CPUQuotaToGOMAXPROCS(minValue int) (int, CPUQuotaStatus, error) {
+	cgroups, err := cg.NewCGroupsForCurrentProcess()
+	if err != nil {
+		return -1, CPUQuotaUndefined, err
+	}
+
+	quota, defined, err := cgroups.CPUQuota()
+	if !defined || err != nil {
+		return -1, CPUQuotaUndefined, err
+	}
+
+	maxProcs := int(math.Floor(quota))
+	if minValue > 0 && maxProcs < minValue {
+		return minValue, CPUQuotaMinUsed, nil
+	}
+	return maxProcs, CPUQuotaUsed, nil
+}

vendor/go.uber.org/automaxprocs/internal/runtime/cpu_quota_unsupported.go

@@ -0,0 +1,30 @@
+// Copyright (c) 2017 Uber Technologies, Inc.
+//
+// Permission is hereby granted, free of charge, to any person obtaining a copy
+// of this software and associated documentation files (the "Software"), to deal
+// in the Software without restriction, including without limitation the rights
+// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+// copies of the Software, and to permit persons to whom the Software is
+// furnished to do so, subject to the following conditions:
+//
+// The above copyright notice and this permission notice shall be included in
+// all copies or substantial portions of the Software.
+//
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+// THE SOFTWARE.
+
+// +build !linux
+
+package runtime
+
+// CPUQuotaToGOMAXPROCS converts the CPU quota applied to the calling process
+// to a valid GOMAXPROCS value. This is Linux-specific and not supported in the
+// current OS.
+func CPUQuotaToGOMAXPROCS(_ int) (int, CPUQuotaStatus, error) {
+	return -1, CPUQuotaUndefined, nil
+}

vendor/go.uber.org/automaxprocs/internal/runtime/runtime.go

@@ -0,0 +1,33 @@
+// Copyright (c) 2017 Uber Technologies, Inc.
+//
+// Permission is hereby granted, free of charge, to any person obtaining a copy
+// of this software and associated documentation files (the "Software"), to deal
+// in the Software without restriction, including without limitation the rights
+// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+// copies of the Software, and to permit persons to whom the Software is
+// furnished to do so, subject to the following conditions:
+//
+// The above copyright notice and this permission notice shall be included in
+// all copies or substantial portions of the Software.
+//
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+// THE SOFTWARE.
+
+package runtime
+
+// CPUQuotaStatus presents the status of how CPU quota is used
+type CPUQuotaStatus int
+
+const (
+	// CPUQuotaUndefined is returned when CPU quota is undefined
+	CPUQuotaUndefined CPUQuotaStatus = iota
+	// CPUQuotaUsed is returned when a valid CPU quota can be used
+	CPUQuotaUsed
+	// CPUQuotaMinUsed is return when CPU quota is smaller than the min value
+	CPUQuotaMinUsed
+)

vendor/go.uber.org/automaxprocs/maxprocs/maxprocs.go

@@ -0,0 +1,130 @@
+// Copyright (c) 2017 Uber Technologies, Inc.
+//
+// Permission is hereby granted, free of charge, to any person obtaining a copy
+// of this software and associated documentation files (the "Software"), to deal
+// in the Software without restriction, including without limitation the rights
+// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+// copies of the Software, and to permit persons to whom the Software is
+// furnished to do so, subject to the following conditions:
+//
+// The above copyright notice and this permission notice shall be included in
+// all copies or substantial portions of the Software.
+//
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+// THE SOFTWARE.
+
+// Package maxprocs lets Go programs easily configure runtime.GOMAXPROCS to
+// match the configured Linux CPU quota. Unlike the top-level automaxprocs
+// package, it lets the caller configure logging and handle errors.
+package maxprocs // import "go.uber.org/automaxprocs/maxprocs"
+
+import (
+	"os"
+	"runtime"
+
+	iruntime "go.uber.org/automaxprocs/internal/runtime"
+)
+
+const _maxProcsKey = "GOMAXPROCS"
+
+func currentMaxProcs() int {
+	return runtime.GOMAXPROCS(0)
+}
+
+type config struct {
+	printf        func(string, ...interface{})
+	procs         func(int) (int, iruntime.CPUQuotaStatus, error)
+	minGOMAXPROCS int
+}
+
+func (c *config) log(fmt string, args ...interface{}) {
+	if c.printf != nil {
+		c.printf(fmt, args...)
+	}
+}
+
+// An Option alters the behavior of Set.
+type Option interface {
+	apply(*config)
+}
+
+// Logger uses the supplied printf implementation for log output. By default,
+// Set doesn't log anything.
+func Logger(printf func(string, ...interface{})) Option {
+	return optionFunc(func(cfg *config) {
+		cfg.printf = printf
+	})
+}
+
+// Min sets the minimum GOMAXPROCS value that will be used.
+// Any value below 1 is ignored.
+func Min(n int) Option {
+	return optionFunc(func(cfg *config) {
+		if n >= 1 {
+			cfg.minGOMAXPROCS = n
+		}
+	})
+}
+
+type optionFunc func(*config)
+
+func (of optionFunc) apply(cfg *config) { of(cfg) }
+
+// Set GOMAXPROCS to match the Linux container CPU quota (if any), returning
+// any error encountered and an undo function.
+//
+// Set is a no-op on non-Linux systems and in Linux environments without a
+// configured CPU quota.
+func Set(opts ...Option) (func(), error) {
+	cfg := &config{
+		procs:         iruntime.CPUQuotaToGOMAXPROCS,
+		minGOMAXPROCS: 1,
+	}
+	for _, o := range opts {
+		o.apply(cfg)
+	}
+
+	undoNoop := func() {
+		cfg.log("maxprocs: No GOMAXPROCS change to reset")
+	}
+
+	// Honor the GOMAXPROCS environment variable if present. Otherwise, amend
+	// `runtime.GOMAXPROCS()` with the current process' CPU quota if the OS is
+	// Linux, and guarantee a minimum value of 1. The minimum guaranteed value
+	// can be overriden using `maxprocs.Min()`.
+	if max, exists := os.LookupEnv(_maxProcsKey); exists {
+		cfg.log("maxprocs: Honoring GOMAXPROCS=%q as set in environment", max)
+		return undoNoop, nil
+	}
+
+	maxProcs, status, err := cfg.procs(cfg.minGOMAXPROCS)
+	if err != nil {
+		return undoNoop, err
+	}
+
+	if status == iruntime.CPUQuotaUndefined {
+		cfg.log("maxprocs: Leaving GOMAXPROCS=%v: CPU quota undefined", currentMaxProcs())
+		return undoNoop, nil
+	}
+
+	prev := currentMaxProcs()
+	undo := func() {
+		cfg.log("maxprocs: Resetting GOMAXPROCS to %v", prev)
+		runtime.GOMAXPROCS(prev)
+	}
+
+	switch status {
+	case iruntime.CPUQuotaMinUsed:
+		cfg.log("maxprocs: Updating GOMAXPROCS=%v: using minimum allowed GOMAXPROCS", maxProcs)
+	case iruntime.CPUQuotaUsed:
+		cfg.log("maxprocs: Updating GOMAXPROCS=%v: determined from CPU quota", maxProcs)
+	}
+
+	runtime.GOMAXPROCS(maxProcs)
+	return undo, nil
+}

vendor/go.uber.org/automaxprocs/maxprocs/version.go

@@ -0,0 +1,24 @@
+// Copyright (c) 2017 Uber Technologies, Inc.
+//
+// Permission is hereby granted, free of charge, to any person obtaining a copy
+// of this software and associated documentation files (the "Software"), to deal
+// in the Software without restriction, including without limitation the rights
+// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+// copies of the Software, and to permit persons to whom the Software is
+// furnished to do so, subject to the following conditions:
+//
+// The above copyright notice and this permission notice shall be included in
+// all copies or substantial portions of the Software.
+//
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+// THE SOFTWARE.
+
+package maxprocs
+
+// Version is the current package version.
+const Version = "1.4.0"

vendor/modules.txt

@@ -250,6 +250,11 @@ github.com/stretchr/testify/require
 ## explicit
 github.com/urfave/cli/v2
 github.com/urfave/cli/v2/altsrc
+# go.uber.org/automaxprocs v1.4.0
+## explicit
+go.uber.org/automaxprocs/internal/cgroups
+go.uber.org/automaxprocs/internal/runtime
+go.uber.org/automaxprocs/maxprocs
 # golang.org/x/crypto v0.0.0-20200820211705-5c72a883971a
 ## explicit
 golang.org/x/crypto/blake2b