/
http_config.go
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/
http_config.go
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// Copyright 2016 The Prometheus Authors
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
// +build go1.8
package config
import (
"bytes"
"crypto/md5"
"crypto/tls"
"crypto/x509"
"fmt"
"io/ioutil"
"net/http"
"net/url"
"strings"
"sync"
"time"
"github.com/mwitkow/go-conntrack"
"golang.org/x/net/http2"
"gopkg.in/yaml.v2"
)
type closeIdler interface {
CloseIdleConnections()
}
// BasicAuth contains basic HTTP authentication credentials.
type BasicAuth struct {
Username string `yaml:"username"`
Password Secret `yaml:"password,omitempty"`
PasswordFile string `yaml:"password_file,omitempty"`
}
// SetDirectory joins any relative file paths with dir.
func (a *BasicAuth) SetDirectory(dir string) {
if a == nil {
return
}
a.PasswordFile = JoinDir(dir, a.PasswordFile)
}
// URL is a custom URL type that allows validation at configuration load time.
type URL struct {
*url.URL
}
// UnmarshalYAML implements the yaml.Unmarshaler interface for URLs.
func (u *URL) UnmarshalYAML(unmarshal func(interface{}) error) error {
var s string
if err := unmarshal(&s); err != nil {
return err
}
urlp, err := url.Parse(s)
if err != nil {
return err
}
u.URL = urlp
return nil
}
// MarshalYAML implements the yaml.Marshaler interface for URLs.
func (u URL) MarshalYAML() (interface{}, error) {
if u.URL != nil {
return u.String(), nil
}
return nil, nil
}
// HTTPClientConfig configures an HTTP client.
type HTTPClientConfig struct {
// The HTTP basic authentication credentials for the targets.
BasicAuth *BasicAuth `yaml:"basic_auth,omitempty"`
// The bearer token for the targets.
BearerToken Secret `yaml:"bearer_token,omitempty"`
// The bearer token file for the targets.
BearerTokenFile string `yaml:"bearer_token_file,omitempty"`
// HTTP proxy server to use to connect to the targets.
ProxyURL URL `yaml:"proxy_url,omitempty"`
// TLSConfig to use to connect to the targets.
TLSConfig TLSConfig `yaml:"tls_config,omitempty"`
}
// SetDirectory joins any relative file paths with dir.
func (c *HTTPClientConfig) SetDirectory(dir string) {
if c == nil {
return
}
c.TLSConfig.SetDirectory(dir)
c.BasicAuth.SetDirectory(dir)
c.BearerTokenFile = JoinDir(dir, c.BearerTokenFile)
}
// Validate validates the HTTPClientConfig to check only one of BearerToken,
// BasicAuth and BearerTokenFile is configured.
func (c *HTTPClientConfig) Validate() error {
if len(c.BearerToken) > 0 && len(c.BearerTokenFile) > 0 {
return fmt.Errorf("at most one of bearer_token & bearer_token_file must be configured")
}
if c.BasicAuth != nil && (len(c.BearerToken) > 0 || len(c.BearerTokenFile) > 0) {
return fmt.Errorf("at most one of basic_auth, bearer_token & bearer_token_file must be configured")
}
if c.BasicAuth != nil && (string(c.BasicAuth.Password) != "" && c.BasicAuth.PasswordFile != "") {
return fmt.Errorf("at most one of basic_auth password & password_file must be configured")
}
return nil
}
// UnmarshalYAML implements the yaml.Unmarshaler interface
func (c *HTTPClientConfig) UnmarshalYAML(unmarshal func(interface{}) error) error {
type plain HTTPClientConfig
if err := unmarshal((*plain)(c)); err != nil {
return err
}
return c.Validate()
}
// UnmarshalYAML implements the yaml.Unmarshaler interface.
func (a *BasicAuth) UnmarshalYAML(unmarshal func(interface{}) error) error {
type plain BasicAuth
return unmarshal((*plain)(a))
}
// NewClient returns a http.Client using the specified http.RoundTripper.
func newClient(rt http.RoundTripper) *http.Client {
return &http.Client{Transport: rt}
}
// NewClientFromConfig returns a new HTTP client configured for the
// given config.HTTPClientConfig. The name is used as go-conntrack metric label.
func NewClientFromConfig(cfg HTTPClientConfig, name string, disableKeepAlives, enableHTTP2 bool) (*http.Client, error) {
rt, err := NewRoundTripperFromConfig(cfg, name, disableKeepAlives, enableHTTP2)
if err != nil {
return nil, err
}
return newClient(rt), nil
}
// NewRoundTripperFromConfig returns a new HTTP RoundTripper configured for the
// given config.HTTPClientConfig. The name is used as go-conntrack metric label.
func NewRoundTripperFromConfig(cfg HTTPClientConfig, name string, disableKeepAlives, enableHTTP2 bool) (http.RoundTripper, error) {
newRT := func(tlsConfig *tls.Config) (http.RoundTripper, error) {
// The only timeout we care about is the configured scrape timeout.
// It is applied on request. So we leave out any timings here.
var rt http.RoundTripper = &http.Transport{
Proxy: http.ProxyURL(cfg.ProxyURL.URL),
MaxIdleConns: 20000,
MaxIdleConnsPerHost: 1000, // see https://github.com/golang/go/issues/13801
DisableKeepAlives: disableKeepAlives,
TLSClientConfig: tlsConfig,
DisableCompression: true,
// 5 minutes is typically above the maximum sane scrape interval. So we can
// use keepalive for all configurations.
IdleConnTimeout: 5 * time.Minute,
TLSHandshakeTimeout: 10 * time.Second,
ExpectContinueTimeout: 1 * time.Second,
DialContext: conntrack.NewDialContextFunc(
conntrack.DialWithTracing(),
conntrack.DialWithName(name),
),
}
if enableHTTP2 {
// HTTP/2 support is golang has many problematic cornercases where
// dead connections would be kept and used in connection pools.
// https://github.com/golang/go/issues/32388
// https://github.com/golang/go/issues/39337
// https://github.com/golang/go/issues/39750
// TODO: Re-Enable HTTP/2 once upstream issue is fixed.
// TODO: use ForceAttemptHTTP2 when we move to Go 1.13+.
err := http2.ConfigureTransport(rt.(*http.Transport))
if err != nil {
return nil, err
}
}
// If a bearer token is provided, create a round tripper that will set the
// Authorization header correctly on each request.
if len(cfg.BearerToken) > 0 {
rt = NewBearerAuthRoundTripper(cfg.BearerToken, rt)
} else if len(cfg.BearerTokenFile) > 0 {
rt = NewBearerAuthFileRoundTripper(cfg.BearerTokenFile, rt)
}
if cfg.BasicAuth != nil {
rt = NewBasicAuthRoundTripper(cfg.BasicAuth.Username, cfg.BasicAuth.Password, cfg.BasicAuth.PasswordFile, rt)
}
// Return a new configured RoundTripper.
return rt, nil
}
tlsConfig, err := NewTLSConfig(&cfg.TLSConfig)
if err != nil {
return nil, err
}
if len(cfg.TLSConfig.CAFile) == 0 {
// No need for a RoundTripper that reloads the CA file automatically.
return newRT(tlsConfig)
}
return newTLSRoundTripper(tlsConfig, cfg.TLSConfig.CAFile, newRT)
}
type bearerAuthRoundTripper struct {
bearerToken Secret
rt http.RoundTripper
}
// NewBearerAuthRoundTripper adds the provided bearer token to a request unless the authorization
// header has already been set.
func NewBearerAuthRoundTripper(token Secret, rt http.RoundTripper) http.RoundTripper {
return &bearerAuthRoundTripper{token, rt}
}
func (rt *bearerAuthRoundTripper) RoundTrip(req *http.Request) (*http.Response, error) {
if len(req.Header.Get("Authorization")) == 0 {
req = cloneRequest(req)
req.Header.Set("Authorization", fmt.Sprintf("Bearer %s", string(rt.bearerToken)))
}
return rt.rt.RoundTrip(req)
}
func (rt *bearerAuthRoundTripper) CloseIdleConnections() {
if ci, ok := rt.rt.(closeIdler); ok {
ci.CloseIdleConnections()
}
}
type bearerAuthFileRoundTripper struct {
bearerFile string
rt http.RoundTripper
}
// NewBearerAuthFileRoundTripper adds the bearer token read from the provided file to a request unless
// the authorization header has already been set. This file is read for every request.
func NewBearerAuthFileRoundTripper(bearerFile string, rt http.RoundTripper) http.RoundTripper {
return &bearerAuthFileRoundTripper{bearerFile, rt}
}
func (rt *bearerAuthFileRoundTripper) RoundTrip(req *http.Request) (*http.Response, error) {
if len(req.Header.Get("Authorization")) == 0 {
b, err := ioutil.ReadFile(rt.bearerFile)
if err != nil {
return nil, fmt.Errorf("unable to read bearer token file %s: %s", rt.bearerFile, err)
}
bearerToken := strings.TrimSpace(string(b))
req = cloneRequest(req)
req.Header.Set("Authorization", "Bearer "+bearerToken)
}
return rt.rt.RoundTrip(req)
}
func (rt *bearerAuthFileRoundTripper) CloseIdleConnections() {
if ci, ok := rt.rt.(closeIdler); ok {
ci.CloseIdleConnections()
}
}
type basicAuthRoundTripper struct {
username string
password Secret
passwordFile string
rt http.RoundTripper
}
// NewBasicAuthRoundTripper will apply a BASIC auth authorization header to a request unless it has
// already been set.
func NewBasicAuthRoundTripper(username string, password Secret, passwordFile string, rt http.RoundTripper) http.RoundTripper {
return &basicAuthRoundTripper{username, password, passwordFile, rt}
}
func (rt *basicAuthRoundTripper) RoundTrip(req *http.Request) (*http.Response, error) {
if len(req.Header.Get("Authorization")) != 0 {
return rt.rt.RoundTrip(req)
}
req = cloneRequest(req)
if rt.passwordFile != "" {
bs, err := ioutil.ReadFile(rt.passwordFile)
if err != nil {
return nil, fmt.Errorf("unable to read basic auth password file %s: %s", rt.passwordFile, err)
}
req.SetBasicAuth(rt.username, strings.TrimSpace(string(bs)))
} else {
req.SetBasicAuth(rt.username, strings.TrimSpace(string(rt.password)))
}
return rt.rt.RoundTrip(req)
}
func (rt *basicAuthRoundTripper) CloseIdleConnections() {
if ci, ok := rt.rt.(closeIdler); ok {
ci.CloseIdleConnections()
}
}
// cloneRequest returns a clone of the provided *http.Request.
// The clone is a shallow copy of the struct and its Header map.
func cloneRequest(r *http.Request) *http.Request {
// Shallow copy of the struct.
r2 := new(http.Request)
*r2 = *r
// Deep copy of the Header.
r2.Header = make(http.Header)
for k, s := range r.Header {
r2.Header[k] = s
}
return r2
}
// NewTLSConfig creates a new tls.Config from the given TLSConfig.
func NewTLSConfig(cfg *TLSConfig) (*tls.Config, error) {
tlsConfig := &tls.Config{InsecureSkipVerify: cfg.InsecureSkipVerify}
// If a CA cert is provided then let's read it in so we can validate the
// scrape target's certificate properly.
if len(cfg.CAFile) > 0 {
b, err := readCAFile(cfg.CAFile)
if err != nil {
return nil, err
}
if !updateRootCA(tlsConfig, b) {
return nil, fmt.Errorf("unable to use specified CA cert %s", cfg.CAFile)
}
}
if len(cfg.ServerName) > 0 {
tlsConfig.ServerName = cfg.ServerName
}
// If a client cert & key is provided then configure TLS config accordingly.
if len(cfg.CertFile) > 0 && len(cfg.KeyFile) == 0 {
return nil, fmt.Errorf("client cert file %q specified without client key file", cfg.CertFile)
} else if len(cfg.KeyFile) > 0 && len(cfg.CertFile) == 0 {
return nil, fmt.Errorf("client key file %q specified without client cert file", cfg.KeyFile)
} else if len(cfg.CertFile) > 0 && len(cfg.KeyFile) > 0 {
// Verify that client cert and key are valid.
if _, err := cfg.getClientCertificate(nil); err != nil {
return nil, err
}
tlsConfig.GetClientCertificate = cfg.getClientCertificate
}
return tlsConfig, nil
}
// TLSConfig configures the options for TLS connections.
type TLSConfig struct {
// The CA cert to use for the targets.
CAFile string `yaml:"ca_file,omitempty"`
// The client cert file for the targets.
CertFile string `yaml:"cert_file,omitempty"`
// The client key file for the targets.
KeyFile string `yaml:"key_file,omitempty"`
// Used to verify the hostname for the targets.
ServerName string `yaml:"server_name,omitempty"`
// Disable target certificate validation.
InsecureSkipVerify bool `yaml:"insecure_skip_verify"`
}
// SetDirectory joins any relative file paths with dir.
func (c *TLSConfig) SetDirectory(dir string) {
if c == nil {
return
}
c.CAFile = JoinDir(dir, c.CAFile)
c.CertFile = JoinDir(dir, c.CertFile)
c.KeyFile = JoinDir(dir, c.KeyFile)
}
// UnmarshalYAML implements the yaml.Unmarshaler interface.
func (c *TLSConfig) UnmarshalYAML(unmarshal func(interface{}) error) error {
type plain TLSConfig
return unmarshal((*plain)(c))
}
// getClientCertificate reads the pair of client cert and key from disk and returns a tls.Certificate.
func (c *TLSConfig) getClientCertificate(*tls.CertificateRequestInfo) (*tls.Certificate, error) {
cert, err := tls.LoadX509KeyPair(c.CertFile, c.KeyFile)
if err != nil {
return nil, fmt.Errorf("unable to use specified client cert (%s) & key (%s): %s", c.CertFile, c.KeyFile, err)
}
return &cert, nil
}
// readCAFile reads the CA cert file from disk.
func readCAFile(f string) ([]byte, error) {
data, err := ioutil.ReadFile(f)
if err != nil {
return nil, fmt.Errorf("unable to load specified CA cert %s: %s", f, err)
}
return data, nil
}
// updateRootCA parses the given byte slice as a series of PEM encoded certificates and updates tls.Config.RootCAs.
func updateRootCA(cfg *tls.Config, b []byte) bool {
caCertPool := x509.NewCertPool()
if !caCertPool.AppendCertsFromPEM(b) {
return false
}
cfg.RootCAs = caCertPool
return true
}
// tlsRoundTripper is a RoundTripper that updates automatically its TLS
// configuration whenever the content of the CA file changes.
type tlsRoundTripper struct {
caFile string
// newRT returns a new RoundTripper.
newRT func(*tls.Config) (http.RoundTripper, error)
mtx sync.RWMutex
rt http.RoundTripper
hashCAFile []byte
tlsConfig *tls.Config
}
func newTLSRoundTripper(
cfg *tls.Config,
caFile string,
newRT func(*tls.Config) (http.RoundTripper, error),
) (http.RoundTripper, error) {
t := &tlsRoundTripper{
caFile: caFile,
newRT: newRT,
tlsConfig: cfg,
}
rt, err := t.newRT(t.tlsConfig)
if err != nil {
return nil, err
}
t.rt = rt
_, t.hashCAFile, err = t.getCAWithHash()
if err != nil {
return nil, err
}
return t, nil
}
func (t *tlsRoundTripper) getCAWithHash() ([]byte, []byte, error) {
b, err := readCAFile(t.caFile)
if err != nil {
return nil, nil, err
}
h := md5.Sum(b)
return b, h[:], nil
}
// RoundTrip implements the http.RoundTrip interface.
func (t *tlsRoundTripper) RoundTrip(req *http.Request) (*http.Response, error) {
b, h, err := t.getCAWithHash()
if err != nil {
return nil, err
}
t.mtx.RLock()
equal := bytes.Equal(h[:], t.hashCAFile)
rt := t.rt
t.mtx.RUnlock()
if equal {
// The CA cert hasn't changed, use the existing RoundTripper.
return rt.RoundTrip(req)
}
// Create a new RoundTripper.
tlsConfig := t.tlsConfig.Clone()
if !updateRootCA(tlsConfig, b) {
return nil, fmt.Errorf("unable to use specified CA cert %s", t.caFile)
}
rt, err = t.newRT(tlsConfig)
if err != nil {
return nil, err
}
t.CloseIdleConnections()
t.mtx.Lock()
t.rt = rt
t.hashCAFile = h[:]
t.mtx.Unlock()
return rt.RoundTrip(req)
}
func (t *tlsRoundTripper) CloseIdleConnections() {
t.mtx.RLock()
defer t.mtx.RUnlock()
if ci, ok := t.rt.(closeIdler); ok {
ci.CloseIdleConnections()
}
}
func (c HTTPClientConfig) String() string {
b, err := yaml.Marshal(c)
if err != nil {
return fmt.Sprintf("<error creating http client config string: %s>", err)
}
return string(b)
}