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tailscale/hostinfo/hostinfo.go

118 lines
2.6 KiB
Go

// Copyright (c) 2020 Tailscale Inc & AUTHORS All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
// Package hostinfo answers questions about the host environment that Tailscale is
// running on.
//
// TODO(bradfitz): move more of control/controlclient/hostinfo_* into this package.
package hostinfo
import (
"io"
"os"
"runtime"
"sync/atomic"
"go4.org/mem"
"tailscale.com/util/lineread"
)
// EnvType represents a known environment type.
// The empty string, the default, means unknown.
type EnvType string
const (
KNative = EnvType("kn")
AWSLambda = EnvType("lm")
Heroku = EnvType("hr")
AzureAppService = EnvType("az")
)
var envType atomic.Value // of EnvType
func GetEnvType() EnvType {
if e, ok := envType.Load().(EnvType); ok {
return e
}
e := getEnvType()
envType.Store(e)
return e
}
func getEnvType() EnvType {
if inKnative() {
return KNative
}
if inAWSLambda() {
return AWSLambda
}
if inHerokuDyno() {
return Heroku
}
if inAzureAppService() {
return AzureAppService
}
return ""
}
// InContainer reports whether we're running in a container.
func InContainer() bool {
if runtime.GOOS != "linux" {
return false
}
var ret bool
lineread.File("/proc/1/cgroup", func(line []byte) error {
if mem.Contains(mem.B(line), mem.S("/docker/")) ||
mem.Contains(mem.B(line), mem.S("/lxc/")) {
ret = true
return io.EOF // arbitrary non-nil error to stop loop
}
return nil
})
lineread.File("/proc/mounts", func(line []byte) error {
if mem.Contains(mem.B(line), mem.S("fuse.lxcfs")) {
ret = true
return io.EOF
}
return nil
})
return ret
}
func inKnative() bool {
// https://cloud.google.com/run/docs/reference/container-contract#env-vars
if os.Getenv("K_REVISION") != "" && os.Getenv("K_CONFIGURATION") != "" &&
os.Getenv("K_SERVICE") != "" && os.Getenv("PORT") != "" {
return true
}
return false
}
func inAWSLambda() bool {
// https://docs.aws.amazon.com/lambda/latest/dg/configuration-envvars.html
if os.Getenv("AWS_LAMBDA_FUNCTION_NAME") != "" &&
os.Getenv("AWS_LAMBDA_FUNCTION_VERSION") != "" &&
os.Getenv("AWS_LAMBDA_INITIALIZATION_TYPE") != "" &&
os.Getenv("AWS_LAMBDA_RUNTIME_API") != "" {
return true
}
return false
}
func inHerokuDyno() bool {
// https://devcenter.heroku.com/articles/dynos#local-environment-variables
if os.Getenv("PORT") != "" && os.Getenv("DYNO") != "" {
return true
}
return false
}
func inAzureAppService() bool {
if os.Getenv("APPSVC_RUN_ZIP") != "" && os.Getenv("WEBSITE_STACK") != "" &&
os.Getenv("WEBSITE_AUTH_AUTO_AAD") != "" {
return true
}
return false
}