Fasthttp support!!

docs/instrumenting.asciidoc

@@ -5,12 +5,13 @@ For each server instrumentation module, a transaction is reported for each handl
 request. The transaction will be stored in the request context, which can be obtained through
 that framework's API. The request context can be used for reporting <<custom-instrumentation-spans, custom spans>>.
 
+* <<builtin-modules-apmhttp>>
+* <<builtin-modules-apmfasthttp>>
 * <<builtin-modules-apmecho>>
 * <<builtin-modules-apmgin>>
 * <<builtin-modules-apmbeego>>
 * <<builtin-modules-apmgorilla>>
 * <<builtin-modules-apmgrpc>>
-* <<builtin-modules-apmhttp>>
 * <<builtin-modules-apmhttprouter>>
 * <<builtin-modules-apmnegroni>>
 * <<builtin-modules-apmlambda>>
@@ -30,6 +31,91 @@ that framework's API. The request context can be used for reporting <<custom-ins
 * <<builtin-modules-apmmongo>>
 * <<builtin-modules-apmawssdkgo>>
 
+[[builtin-modules-apmhttp]]
+==== module/apmhttp
+Package apmhttp provides a low-level `net/http` middleware handler. Other web middleware should
+typically be based off this.
+
+For each request, a transaction is stored in the request context, which can be obtained via
+https://golang.org/pkg/net/http/#Request.Context[http.Request.Context] in your handler.
+
+[source,go]
+----
+import (
+	"go.elastic.co/apm/module/apmhttp"
+)
+
+func main() {
+	var myHandler http.Handler = ...
+	tracedHandler := apmhttp.Wrap(myHandler)
+}
+----
+
+The apmhttp handler will recover panics and send them to Elastic APM.
+
+Package apmhttp also provides functions for instrumenting an `http.Client` or `http.RoundTripper`
+such that outgoing requests are traced as spans, if the request context includes a transaction.
+When performing the request, the enclosing context should be propagated by using
+https://golang.org/pkg/net/http/#Request.WithContext[http.Request.WithContext], or a helper, such as those provided by https://golang.org/x/net/context/ctxhttp.
+
+Client spans are not ended until the response body is fully consumed or closed.
+If you fail to do either, the span will not be sent.
+Always close the response body to ensure HTTP connections can be reused; see https://golang.org/pkg/net/http/#Client.Do[`func (*Client) Do`].
+
+[source,go]
+----
+import (
+	"net/http"
+
+	"golang.org/x/net/context/ctxhttp"
+
+	"go.elastic.co/apm"
+	"go.elastic.co/apm/module/apmhttp"
+)
+
+var tracingClient = apmhttp.WrapClient(http.DefaultClient)
+
+func serverHandler(w http.ResponseWriter, req *http.Request) {
+	// Propagate the transaction context contained in req.Context().
+	resp, err := ctxhttp.Get(req.Context(), tracingClient, "http://backend.local/foo")
+	if err != nil {
+		apm.CaptureError(req.Context(), err).Send()
+		http.Error(w, "failed to query backend", 500)
+		return
+	}
+	body, err := ioutil.ReadAll(resp.Body)
+	...
+}
+
+func main() {
+	http.ListenAndServe(":8080", apmhttp.Wrap(http.HandlerFunc(serverHandler)))
+}
+----
+
+[[builtin-modules-apmfasthttp]]
+==== module/apmfasthttp
+Package apmfasthttp provides a low-level https://github.com/valyala/fasthttp[valyala/fasthttp] middleware request handler. Other fasthttp-based web middleware should typically be based off this.
+
+For each request, a transaction is stored in the request context, which can be obtained via
+https://pkg.go.dev/github.com/valyala/fasthttp#RequestCtx[fasthttp.RequestCtx] in your handler using `apm.TransactionFromContext`.
+
+[source,go]
+----
+import (
+	"go.elastic.co/apm/module/apmfasthttp"
+)
+
+func main() {
+	var myHandler fasthttp.RequestHandler = func(ctx *fasthttp.RequestCtx) {
+		apmCtx := apm.TransactionFromContext(ctx)
+		// ...
+	}
+	tracedHandler := apmfasthttp.Wrap(myHandler)
+}
+----
+
+The apmfasthttp handler will recover panics and send them to Elastic APM.
+
 [[builtin-modules-apmecho]]
 ==== module/apmecho
 Packages apmecho and apmechov4 provide middleware for the https://github.com/labstack/echo[Echo]
@@ -185,67 +271,6 @@ fails; when any of `grpc.ClientStream.RecvMsg`, `grpc.ClientStream.SendMsg`, or
 `grpc.ClientStream.Header` return with an error; or when `grpc.ClientStream.RecvMsg`
 returns for a non-streaming server method.
 
-[[builtin-modules-apmhttp]]
-==== module/apmhttp
-Package apmhttp provides a low-level `net/http` middleware handler. Other web middleware should
-typically be based off this.
-
-For each request, a transaction is stored in the request context, which can be obtained via
-https://golang.org/pkg/net/http/#Request.Context[http.Request.Context] in your handler.
-
-[source,go]
-----
-import (
-	"go.elastic.co/apm/module/apmhttp"
-)
-
-func main() {
-	var myHandler http.Handler = ...
-	tracedHandler := apmhttp.Wrap(myHandler)
-}
-----
-
-The apmhttp handler will recover panics and send them to Elastic APM.
-
-Package apmhttp also provides functions for instrumenting an `http.Client` or `http.RoundTripper`
-such that outgoing requests are traced as spans, if the request context includes a transaction.
-When performing the request, the enclosing context should be propagated by using
-https://golang.org/pkg/net/http/#Request.WithContext[http.Request.WithContext], or a helper, such as those provided by https://golang.org/x/net/context/ctxhttp.
-
-Client spans are not ended until the response body is fully consumed or closed.
-If you fail to do either, the span will not be sent.
-Always close the response body to ensure HTTP connections can be reused; see https://golang.org/pkg/net/http/#Client.Do[`func (*Client) Do`].
-
-[source,go]
-----
-import (
-	"net/http"
-
-	"golang.org/x/net/context/ctxhttp"
-
-	"go.elastic.co/apm"
-	"go.elastic.co/apm/module/apmhttp"
-)
-
-var tracingClient = apmhttp.WrapClient(http.DefaultClient)
-
-func serverHandler(w http.ResponseWriter, req *http.Request) {
-	// Propagate the transaction context contained in req.Context().
-	resp, err := ctxhttp.Get(req.Context(), tracingClient, "http://backend.local/foo")
-	if err != nil {
-		apm.CaptureError(req.Context(), err).Send()
-		http.Error(w, "failed to query backend", 500)
-		return
-	}
-	body, err := ioutil.ReadAll(resp.Body)
-	...
-}
-
-func main() {
-	http.ListenAndServe(":8080", apmhttp.Wrap(http.HandlerFunc(serverHandler)))
-}
-----
-
 [[builtin-modules-apmhttprouter]]
 ==== module/apmhttprouter
 Package apmhttprouter provides a low-level middleware handler for https://github.com/julienschmidt/httprouter[httprouter].

docs/supported-tech.asciidoc

@@ -31,6 +31,15 @@ We support several third-party web frameworks, as well as Go's standard `net/htt
 package. Regardless of the framework, we create a transaction for each incoming
 request, and name the transaction after the registered route.
 
+[float]
+==== fasthttp
+
+We support https://github.com/valyala/fasthttp[valyala/fasthttp],
+https://github.com/valyala/fasthttp/releases/tag/v1.26.0[v1.26.0] and greater.
+
+See <<builtin-modules-apmfasthttp, module/apmfasthttp>> for more information
+about fasthttp instrumentation.
+
 [float]
 ==== httprouter
 

gocontext.go

@@ -23,8 +23,6 @@ import (
 	"go.elastic.co/apm/internal/apmcontext"
 )
 
-type bodyCapturerKey struct{}
-
 // ContextWithSpan returns a copy of parent in which the given span
 // is stored, associated with the key ContextSpanKey.
 func ContextWithSpan(parent context.Context, s *Span) context.Context {
@@ -40,7 +38,7 @@ func ContextWithTransaction(parent context.Context, t *Transaction) context.Cont
 // ContextWithBodyCapturer returns a copy of parent in which the given
 // body capturer is stored, associated with the key bodyCapturerKey.
 func ContextWithBodyCapturer(parent context.Context, bc *BodyCapturer) context.Context {
-	return context.WithValue(parent, bodyCapturerKey{}, bc)
+	return apmcontext.ContextWithBodyCapturer(parent, bc)
 }
 
 // SpanFromContext returns the current Span in context, if any. The span must
@@ -59,8 +57,11 @@ func TransactionFromContext(ctx context.Context) *Transaction {
 	return value
 }
 
-func bodyCapturerFromContext(ctx context.Context) *BodyCapturer {
-	value, _ := ctx.Value(bodyCapturerKey{}).(*BodyCapturer)
+// BodyCapturerFromContext returns the BodyCapturer in context, if any.
+// The body capturer must have been added to the context previously using
+// ContextWithBodyCapturer.
+func BodyCapturerFromContext(ctx context.Context) *BodyCapturer {
+	value, _ := apmcontext.BodyCapturerFromContext(ctx).(*BodyCapturer)
 	return value
 }
 
@@ -143,7 +144,7 @@ func CaptureError(ctx context.Context, err error) *Error {
 		}
 		e := tx.tracer.NewError(err)
 		e.Handled = true
-		bc := bodyCapturerFromContext(ctx)
+		bc := BodyCapturerFromContext(ctx)
 		if bc != nil {
 			e.Context.SetHTTPRequest(bc.request)
 			e.Context.SetHTTPRequestBody(bc)

internal/apmcontext/context.go

@@ -39,6 +39,15 @@ var (
 	// it at package init time.
 	ContextWithTransaction = DefaultContextWithTransaction
 
+	// ContextWithBodyCapturer takes a context and body capturer and returns
+	// a new context from which the body capturer can be extracted using
+	// BodyCapturerFromContext.
+	//
+	// ContextWithBodyCapturer is used by apm.ContextWithBodyCapturer.
+	// It is a variable to allow other packages, such as apmot, to replace
+	// it at package init time.
+	ContextWithBodyCapturer = DefaultContextWithBodyCapturer
+
 	// SpanFromContext returns a span included in the context using
 	// ContextWithSpan.
 	//
@@ -54,10 +63,19 @@ var (
 	// It is a variable to allow other packages, such as apmot, to replace
 	// it at package init time.
 	TransactionFromContext = DefaultTransactionFromContext
+
+	// BodyCapturerFromContext returns a body capturer included in the context
+	// using ContextWithBodyCapturer.
+	//
+	// BodyCapturerFromContext is used by apm.BodyCapturerFromContext.
+	// It is a variable to allow other packages, such as apmot, to replace
+	// it at package init time.
+	BodyCapturerFromContext = DefaultBodyCapturerFromContext
 )
 
 type spanKey struct{}
 type transactionKey struct{}
+type bodyCapturerKey struct{}
 
 // DefaultContextWithSpan is the default value for ContextWithSpan.
 func DefaultContextWithSpan(ctx context.Context, span interface{}) context.Context {
@@ -69,6 +87,11 @@ func DefaultContextWithTransaction(ctx context.Context, tx interface{}) context.
 	return context.WithValue(ctx, transactionKey{}, tx)
 }
 
+// DefaultContextWithBodyCapturer is the default value for ContextWithBodyCapturer.
+func DefaultContextWithBodyCapturer(ctx context.Context, bc interface{}) context.Context {
+	return context.WithValue(ctx, bodyCapturerKey{}, bc)
+}
+
 // DefaultSpanFromContext is the default value for SpanFromContext.
 func DefaultSpanFromContext(ctx context.Context) interface{} {
 	return ctx.Value(spanKey{})
@@ -78,3 +101,8 @@ func DefaultSpanFromContext(ctx context.Context) interface{} {
 func DefaultTransactionFromContext(ctx context.Context) interface{} {
 	return ctx.Value(transactionKey{})
 }
+
+// DefaultBodyCapturerFromContext is the default value for BodyCapturerFromContext.
+func DefaultBodyCapturerFromContext(ctx context.Context) interface{} {
+	return ctx.Value(bodyCapturerKey{})
+}

module/apmfasthttp/closer.go

@@ -0,0 +1,47 @@
+// Licensed to Elasticsearch B.V. under one or more contributor
+// license agreements. See the NOTICE file distributed with
+// this work for additional information regarding copyright
+// ownership. Elasticsearch B.V. licenses this file to you 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 go1.12
+
+package apmfasthttp // import "go.elastic.co/apm/module/apmfasthttp"
+
+import (
+	"github.com/valyala/fasthttp"
+
+	"go.elastic.co/apm"
+)
+
+// newTxCloser returns a transaction closer.
+func newTxCloser(ctx *fasthttp.RequestCtx, tx *apm.Transaction, bc *apm.BodyCapturer) *txCloser {
+	return &txCloser{
+		ctx: ctx,
+		tx:  tx,
+		bc:  bc,
+	}
+}
+
+// Close sets the response context to the APM transaction and
+// ends the transaction.
+func (c *txCloser) Close() error {
+	if err := setResponseContext(c.ctx, c.tx, c.bc); err != nil {
+		return err
+	}
+
+	c.tx.End()
+
+	return nil
+}

module/apmfasthttp/consts.go

@@ -0,0 +1,22 @@
+// Licensed to Elasticsearch B.V. under one or more contributor
+// license agreements. See the NOTICE file distributed with
+// this work for additional information regarding copyright
+// ownership. Elasticsearch B.V. licenses this file to you 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 go1.12
+
+package apmfasthttp // import "go.elastic.co/apm/module/apmfasthttp"
+
+const txKey = "apmfasthttp_transaction"