1 files changed, 130 insertions, 0 deletions
diff --git a/vendor/go.uber.org/automaxprocs/maxprocs/maxprocs.go b/vendor/go.uber.org/automaxprocs/maxprocs/maxprocs.go
new file mode 100644
index 000000000..98176d645
--- /dev/null
+++ b/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 overridden 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
+}