Vendor integration dependencies.

This commit is contained in:
Timo Reimann 2017-02-07 22:33:23 +01:00
parent dd5e3fba01
commit 55b57c736b
2451 changed files with 731611 additions and 0 deletions

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package context
import (
"sync"
"github.com/docker/distribution/uuid"
"golang.org/x/net/context"
)
// Context is a copy of Context from the golang.org/x/net/context package.
type Context interface {
context.Context
}
// instanceContext is a context that provides only an instance id. It is
// provided as the main background context.
type instanceContext struct {
Context
id string // id of context, logged as "instance.id"
once sync.Once // once protect generation of the id
}
func (ic *instanceContext) Value(key interface{}) interface{} {
if key == "instance.id" {
ic.once.Do(func() {
// We want to lazy initialize the UUID such that we don't
// call a random generator from the package initialization
// code. For various reasons random could not be available
// https://github.com/docker/distribution/issues/782
ic.id = uuid.Generate().String()
})
return ic.id
}
return ic.Context.Value(key)
}
var background = &instanceContext{
Context: context.Background(),
}
// Background returns a non-nil, empty Context. The background context
// provides a single key, "instance.id" that is globally unique to the
// process.
func Background() Context {
return background
}
// WithValue returns a copy of parent in which the value associated with key is
// val. Use context Values only for request-scoped data that transits processes
// and APIs, not for passing optional parameters to functions.
func WithValue(parent Context, key, val interface{}) Context {
return context.WithValue(parent, key, val)
}
// stringMapContext is a simple context implementation that checks a map for a
// key, falling back to a parent if not present.
type stringMapContext struct {
context.Context
m map[string]interface{}
}
// WithValues returns a context that proxies lookups through a map. Only
// supports string keys.
func WithValues(ctx context.Context, m map[string]interface{}) context.Context {
mo := make(map[string]interface{}, len(m)) // make our own copy.
for k, v := range m {
mo[k] = v
}
return stringMapContext{
Context: ctx,
m: mo,
}
}
func (smc stringMapContext) Value(key interface{}) interface{} {
if ks, ok := key.(string); ok {
if v, ok := smc.m[ks]; ok {
return v
}
}
return smc.Context.Value(key)
}

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// Package context provides several utilities for working with
// golang.org/x/net/context in http requests. Primarily, the focus is on
// logging relevant request information but this package is not limited to
// that purpose.
//
// The easiest way to get started is to get the background context:
//
// ctx := context.Background()
//
// The returned context should be passed around your application and be the
// root of all other context instances. If the application has a version, this
// line should be called before anything else:
//
// ctx := context.WithVersion(context.Background(), version)
//
// The above will store the version in the context and will be available to
// the logger.
//
// Logging
//
// The most useful aspect of this package is GetLogger. This function takes
// any context.Context interface and returns the current logger from the
// context. Canonical usage looks like this:
//
// GetLogger(ctx).Infof("something interesting happened")
//
// GetLogger also takes optional key arguments. The keys will be looked up in
// the context and reported with the logger. The following example would
// return a logger that prints the version with each log message:
//
// ctx := context.Context(context.Background(), "version", version)
// GetLogger(ctx, "version").Infof("this log message has a version field")
//
// The above would print out a log message like this:
//
// INFO[0000] this log message has a version field version=v2.0.0-alpha.2.m
//
// When used with WithLogger, we gain the ability to decorate the context with
// loggers that have information from disparate parts of the call stack.
// Following from the version example, we can build a new context with the
// configured logger such that we always print the version field:
//
// ctx = WithLogger(ctx, GetLogger(ctx, "version"))
//
// Since the logger has been pushed to the context, we can now get the version
// field for free with our log messages. Future calls to GetLogger on the new
// context will have the version field:
//
// GetLogger(ctx).Infof("this log message has a version field")
//
// This becomes more powerful when we start stacking loggers. Let's say we
// have the version logger from above but also want a request id. Using the
// context above, in our request scoped function, we place another logger in
// the context:
//
// ctx = context.WithValue(ctx, "http.request.id", "unique id") // called when building request context
// ctx = WithLogger(ctx, GetLogger(ctx, "http.request.id"))
//
// When GetLogger is called on the new context, "http.request.id" will be
// included as a logger field, along with the original "version" field:
//
// INFO[0000] this log message has a version field http.request.id=unique id version=v2.0.0-alpha.2.m
//
// Note that this only affects the new context, the previous context, with the
// version field, can be used independently. Put another way, the new logger,
// added to the request context, is unique to that context and can have
// request scoped varaibles.
//
// HTTP Requests
//
// This package also contains several methods for working with http requests.
// The concepts are very similar to those described above. We simply place the
// request in the context using WithRequest. This makes the request variables
// available. GetRequestLogger can then be called to get request specific
// variables in a log line:
//
// ctx = WithRequest(ctx, req)
// GetRequestLogger(ctx).Infof("request variables")
//
// Like above, if we want to include the request data in all log messages in
// the context, we push the logger to a new context and use that one:
//
// ctx = WithLogger(ctx, GetRequestLogger(ctx))
//
// The concept is fairly powerful and ensures that calls throughout the stack
// can be traced in log messages. Using the fields like "http.request.id", one
// can analyze call flow for a particular request with a simple grep of the
// logs.
package context

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package context
import (
"errors"
"net"
"net/http"
"strings"
"sync"
"time"
log "github.com/Sirupsen/logrus"
"github.com/docker/distribution/uuid"
"github.com/gorilla/mux"
)
// Common errors used with this package.
var (
ErrNoRequestContext = errors.New("no http request in context")
ErrNoResponseWriterContext = errors.New("no http response in context")
)
func parseIP(ipStr string) net.IP {
ip := net.ParseIP(ipStr)
if ip == nil {
log.Warnf("invalid remote IP address: %q", ipStr)
}
return ip
}
// RemoteAddr extracts the remote address of the request, taking into
// account proxy headers.
func RemoteAddr(r *http.Request) string {
if prior := r.Header.Get("X-Forwarded-For"); prior != "" {
proxies := strings.Split(prior, ",")
if len(proxies) > 0 {
remoteAddr := strings.Trim(proxies[0], " ")
if parseIP(remoteAddr) != nil {
return remoteAddr
}
}
}
// X-Real-Ip is less supported, but worth checking in the
// absence of X-Forwarded-For
if realIP := r.Header.Get("X-Real-Ip"); realIP != "" {
if parseIP(realIP) != nil {
return realIP
}
}
return r.RemoteAddr
}
// RemoteIP extracts the remote IP of the request, taking into
// account proxy headers.
func RemoteIP(r *http.Request) string {
addr := RemoteAddr(r)
// Try parsing it as "IP:port"
if ip, _, err := net.SplitHostPort(addr); err == nil {
return ip
}
return addr
}
// WithRequest places the request on the context. The context of the request
// is assigned a unique id, available at "http.request.id". The request itself
// is available at "http.request". Other common attributes are available under
// the prefix "http.request.". If a request is already present on the context,
// this method will panic.
func WithRequest(ctx Context, r *http.Request) Context {
if ctx.Value("http.request") != nil {
// NOTE(stevvooe): This needs to be considered a programming error. It
// is unlikely that we'd want to have more than one request in
// context.
panic("only one request per context")
}
return &httpRequestContext{
Context: ctx,
startedAt: time.Now(),
id: uuid.Generate().String(),
r: r,
}
}
// GetRequest returns the http request in the given context. Returns
// ErrNoRequestContext if the context does not have an http request associated
// with it.
func GetRequest(ctx Context) (*http.Request, error) {
if r, ok := ctx.Value("http.request").(*http.Request); r != nil && ok {
return r, nil
}
return nil, ErrNoRequestContext
}
// GetRequestID attempts to resolve the current request id, if possible. An
// error is return if it is not available on the context.
func GetRequestID(ctx Context) string {
return GetStringValue(ctx, "http.request.id")
}
// WithResponseWriter returns a new context and response writer that makes
// interesting response statistics available within the context.
func WithResponseWriter(ctx Context, w http.ResponseWriter) (Context, http.ResponseWriter) {
if closeNotifier, ok := w.(http.CloseNotifier); ok {
irwCN := &instrumentedResponseWriterCN{
instrumentedResponseWriter: instrumentedResponseWriter{
ResponseWriter: w,
Context: ctx,
},
CloseNotifier: closeNotifier,
}
return irwCN, irwCN
}
irw := instrumentedResponseWriter{
ResponseWriter: w,
Context: ctx,
}
return &irw, &irw
}
// GetResponseWriter returns the http.ResponseWriter from the provided
// context. If not present, ErrNoResponseWriterContext is returned. The
// returned instance provides instrumentation in the context.
func GetResponseWriter(ctx Context) (http.ResponseWriter, error) {
v := ctx.Value("http.response")
rw, ok := v.(http.ResponseWriter)
if !ok || rw == nil {
return nil, ErrNoResponseWriterContext
}
return rw, nil
}
// getVarsFromRequest let's us change request vars implementation for testing
// and maybe future changes.
var getVarsFromRequest = mux.Vars
// WithVars extracts gorilla/mux vars and makes them available on the returned
// context. Variables are available at keys with the prefix "vars.". For
// example, if looking for the variable "name", it can be accessed as
// "vars.name". Implementations that are accessing values need not know that
// the underlying context is implemented with gorilla/mux vars.
func WithVars(ctx Context, r *http.Request) Context {
return &muxVarsContext{
Context: ctx,
vars: getVarsFromRequest(r),
}
}
// GetRequestLogger returns a logger that contains fields from the request in
// the current context. If the request is not available in the context, no
// fields will display. Request loggers can safely be pushed onto the context.
func GetRequestLogger(ctx Context) Logger {
return GetLogger(ctx,
"http.request.id",
"http.request.method",
"http.request.host",
"http.request.uri",
"http.request.referer",
"http.request.useragent",
"http.request.remoteaddr",
"http.request.contenttype")
}
// GetResponseLogger reads the current response stats and builds a logger.
// Because the values are read at call time, pushing a logger returned from
// this function on the context will lead to missing or invalid data. Only
// call this at the end of a request, after the response has been written.
func GetResponseLogger(ctx Context) Logger {
l := getLogrusLogger(ctx,
"http.response.written",
"http.response.status",
"http.response.contenttype")
duration := Since(ctx, "http.request.startedat")
if duration > 0 {
l = l.WithField("http.response.duration", duration.String())
}
return l
}
// httpRequestContext makes information about a request available to context.
type httpRequestContext struct {
Context
startedAt time.Time
id string
r *http.Request
}
// Value returns a keyed element of the request for use in the context. To get
// the request itself, query "request". For other components, access them as
// "request.<component>". For example, r.RequestURI
func (ctx *httpRequestContext) Value(key interface{}) interface{} {
if keyStr, ok := key.(string); ok {
if keyStr == "http.request" {
return ctx.r
}
if !strings.HasPrefix(keyStr, "http.request.") {
goto fallback
}
parts := strings.Split(keyStr, ".")
if len(parts) != 3 {
goto fallback
}
switch parts[2] {
case "uri":
return ctx.r.RequestURI
case "remoteaddr":
return RemoteAddr(ctx.r)
case "method":
return ctx.r.Method
case "host":
return ctx.r.Host
case "referer":
referer := ctx.r.Referer()
if referer != "" {
return referer
}
case "useragent":
return ctx.r.UserAgent()
case "id":
return ctx.id
case "startedat":
return ctx.startedAt
case "contenttype":
ct := ctx.r.Header.Get("Content-Type")
if ct != "" {
return ct
}
}
}
fallback:
return ctx.Context.Value(key)
}
type muxVarsContext struct {
Context
vars map[string]string
}
func (ctx *muxVarsContext) Value(key interface{}) interface{} {
if keyStr, ok := key.(string); ok {
if keyStr == "vars" {
return ctx.vars
}
if strings.HasPrefix(keyStr, "vars.") {
keyStr = strings.TrimPrefix(keyStr, "vars.")
}
if v, ok := ctx.vars[keyStr]; ok {
return v
}
}
return ctx.Context.Value(key)
}
// instrumentedResponseWriterCN provides response writer information in a
// context. It implements http.CloseNotifier so that users can detect
// early disconnects.
type instrumentedResponseWriterCN struct {
instrumentedResponseWriter
http.CloseNotifier
}
// instrumentedResponseWriter provides response writer information in a
// context. This variant is only used in the case where CloseNotifier is not
// implemented by the parent ResponseWriter.
type instrumentedResponseWriter struct {
http.ResponseWriter
Context
mu sync.Mutex
status int
written int64
}
func (irw *instrumentedResponseWriter) Write(p []byte) (n int, err error) {
n, err = irw.ResponseWriter.Write(p)
irw.mu.Lock()
irw.written += int64(n)
// Guess the likely status if not set.
if irw.status == 0 {
irw.status = http.StatusOK
}
irw.mu.Unlock()
return
}
func (irw *instrumentedResponseWriter) WriteHeader(status int) {
irw.ResponseWriter.WriteHeader(status)
irw.mu.Lock()
irw.status = status
irw.mu.Unlock()
}
func (irw *instrumentedResponseWriter) Flush() {
if flusher, ok := irw.ResponseWriter.(http.Flusher); ok {
flusher.Flush()
}
}
func (irw *instrumentedResponseWriter) Value(key interface{}) interface{} {
if keyStr, ok := key.(string); ok {
if keyStr == "http.response" {
return irw
}
if !strings.HasPrefix(keyStr, "http.response.") {
goto fallback
}
parts := strings.Split(keyStr, ".")
if len(parts) != 3 {
goto fallback
}
irw.mu.Lock()
defer irw.mu.Unlock()
switch parts[2] {
case "written":
return irw.written
case "status":
return irw.status
case "contenttype":
contentType := irw.Header().Get("Content-Type")
if contentType != "" {
return contentType
}
}
}
fallback:
return irw.Context.Value(key)
}
func (irw *instrumentedResponseWriterCN) Value(key interface{}) interface{} {
if keyStr, ok := key.(string); ok {
if keyStr == "http.response" {
return irw
}
}
return irw.instrumentedResponseWriter.Value(key)
}

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package context
import (
"fmt"
"github.com/Sirupsen/logrus"
"runtime"
)
// Logger provides a leveled-logging interface.
type Logger interface {
// standard logger methods
Print(args ...interface{})
Printf(format string, args ...interface{})
Println(args ...interface{})
Fatal(args ...interface{})
Fatalf(format string, args ...interface{})
Fatalln(args ...interface{})
Panic(args ...interface{})
Panicf(format string, args ...interface{})
Panicln(args ...interface{})
// Leveled methods, from logrus
Debug(args ...interface{})
Debugf(format string, args ...interface{})
Debugln(args ...interface{})
Error(args ...interface{})
Errorf(format string, args ...interface{})
Errorln(args ...interface{})
Info(args ...interface{})
Infof(format string, args ...interface{})
Infoln(args ...interface{})
Warn(args ...interface{})
Warnf(format string, args ...interface{})
Warnln(args ...interface{})
}
// WithLogger creates a new context with provided logger.
func WithLogger(ctx Context, logger Logger) Context {
return WithValue(ctx, "logger", logger)
}
// GetLoggerWithField returns a logger instance with the specified field key
// and value without affecting the context. Extra specified keys will be
// resolved from the context.
func GetLoggerWithField(ctx Context, key, value interface{}, keys ...interface{}) Logger {
return getLogrusLogger(ctx, keys...).WithField(fmt.Sprint(key), value)
}
// GetLoggerWithFields returns a logger instance with the specified fields
// without affecting the context. Extra specified keys will be resolved from
// the context.
func GetLoggerWithFields(ctx Context, fields map[interface{}]interface{}, keys ...interface{}) Logger {
// must convert from interface{} -> interface{} to string -> interface{} for logrus.
lfields := make(logrus.Fields, len(fields))
for key, value := range fields {
lfields[fmt.Sprint(key)] = value
}
return getLogrusLogger(ctx, keys...).WithFields(lfields)
}
// GetLogger returns the logger from the current context, if present. If one
// or more keys are provided, they will be resolved on the context and
// included in the logger. While context.Value takes an interface, any key
// argument passed to GetLogger will be passed to fmt.Sprint when expanded as
// a logging key field. If context keys are integer constants, for example,
// its recommended that a String method is implemented.
func GetLogger(ctx Context, keys ...interface{}) Logger {
return getLogrusLogger(ctx, keys...)
}
// GetLogrusLogger returns the logrus logger for the context. If one more keys
// are provided, they will be resolved on the context and included in the
// logger. Only use this function if specific logrus functionality is
// required.
func getLogrusLogger(ctx Context, keys ...interface{}) *logrus.Entry {
var logger *logrus.Entry
// Get a logger, if it is present.
loggerInterface := ctx.Value("logger")
if loggerInterface != nil {
if lgr, ok := loggerInterface.(*logrus.Entry); ok {
logger = lgr
}
}
if logger == nil {
fields := logrus.Fields{}
// Fill in the instance id, if we have it.
instanceID := ctx.Value("instance.id")
if instanceID != nil {
fields["instance.id"] = instanceID
}
fields["go.version"] = runtime.Version()
// If no logger is found, just return the standard logger.
logger = logrus.StandardLogger().WithFields(fields)
}
fields := logrus.Fields{}
for _, key := range keys {
v := ctx.Value(key)
if v != nil {
fields[fmt.Sprint(key)] = v
}
}
return logger.WithFields(fields)
}

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package context
import (
"runtime"
"time"
"github.com/docker/distribution/uuid"
)
// WithTrace allocates a traced timing span in a new context. This allows a
// caller to track the time between calling WithTrace and the returned done
// function. When the done function is called, a log message is emitted with a
// "trace.duration" field, corresponding to the elapsed time and a
// "trace.func" field, corresponding to the function that called WithTrace.
//
// The logging keys "trace.id" and "trace.parent.id" are provided to implement
// dapper-like tracing. This function should be complemented with a WithSpan
// method that could be used for tracing distributed RPC calls.
//
// The main benefit of this function is to post-process log messages or
// intercept them in a hook to provide timing data. Trace ids and parent ids
// can also be linked to provide call tracing, if so required.
//
// Here is an example of the usage:
//
// func timedOperation(ctx Context) {
// ctx, done := WithTrace(ctx)
// defer done("this will be the log message")
// // ... function body ...
// }
//
// If the function ran for roughly 1s, such a usage would emit a log message
// as follows:
//
// INFO[0001] this will be the log message trace.duration=1.004575763s trace.func=github.com/docker/distribution/context.traceOperation trace.id=<id> ...
//
// Notice that the function name is automatically resolved, along with the
// package and a trace id is emitted that can be linked with parent ids.
func WithTrace(ctx Context) (Context, func(format string, a ...interface{})) {
if ctx == nil {
ctx = Background()
}
pc, file, line, _ := runtime.Caller(1)
f := runtime.FuncForPC(pc)
ctx = &traced{
Context: ctx,
id: uuid.Generate().String(),
start: time.Now(),
parent: GetStringValue(ctx, "trace.id"),
fnname: f.Name(),
file: file,
line: line,
}
return ctx, func(format string, a ...interface{}) {
GetLogger(ctx,
"trace.duration",
"trace.id",
"trace.parent.id",
"trace.func",
"trace.file",
"trace.line").
Debugf(format, a...)
}
}
// traced represents a context that is traced for function call timing. It
// also provides fast lookup for the various attributes that are available on
// the trace.
type traced struct {
Context
id string
parent string
start time.Time
fnname string
file string
line int
}
func (ts *traced) Value(key interface{}) interface{} {
switch key {
case "trace.start":
return ts.start
case "trace.duration":
return time.Since(ts.start)
case "trace.id":
return ts.id
case "trace.parent.id":
if ts.parent == "" {
return nil // must return nil to signal no parent.
}
return ts.parent
case "trace.func":
return ts.fnname
case "trace.file":
return ts.file
case "trace.line":
return ts.line
}
return ts.Context.Value(key)
}

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package context
import (
"time"
)
// Since looks up key, which should be a time.Time, and returns the duration
// since that time. If the key is not found, the value returned will be zero.
// This is helpful when inferring metrics related to context execution times.
func Since(ctx Context, key interface{}) time.Duration {
if startedAt, ok := ctx.Value(key).(time.Time); ok {
return time.Since(startedAt)
}
return 0
}
// GetStringValue returns a string value from the context. The empty string
// will be returned if not found.
func GetStringValue(ctx Context, key interface{}) (value string) {
if valuev, ok := ctx.Value(key).(string); ok {
value = valuev
}
return value
}

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package context
// WithVersion stores the application version in the context. The new context
// gets a logger to ensure log messages are marked with the application
// version.
func WithVersion(ctx Context, version string) Context {
ctx = WithValue(ctx, "version", version)
// push a new logger onto the stack
return WithLogger(ctx, GetLogger(ctx, "version"))
}
// GetVersion returns the application version from the context. An empty
// string may returned if the version was not set on the context.
func GetVersion(ctx Context) string {
return GetStringValue(ctx, "version")
}