example: adds http_body_chunk (#421)

examples/http_body_chunk/README.md

@@ -0,0 +1,28 @@
+## http_body_chunk
+
+This example demonstrates how to perform operations on a request body, chunk by chunk.
+
+Reading the received body chunk by chunk, it looks for the string `pattern` inside the body. If it finds it, a 403 response is returned providing the number of the chunk where the pattern was found. Logs are printed every time a chunk is received providing also the size of the read chunk.
+
+Build and run the example:
+```bash
+$ make build.example name=http_body_chunk
+$ make run name=http_body_chunk
+```
+
+Perform a request with a body containing the string `pattern`:
+```bash
+$ head -c 700000 /dev/urandom | base64 > /tmp/file.txt && echo "pattern" >> /tmp/file.txt && curl 'localhost:18000/anything' -d @/tmp/file.txt
+pattern found in chunk: 2
+```
+
+Generated logs:
+```
+wasm log: OnHttpRequestBody called. BodySize: 114532, totalRequestBodyReadSize: 0, endOfStream: false
+wasm log: read chunk size: 114532
+wasm log: OnHttpRequestBody called. BodySize: 114532, totalRequestBodyReadSize: 114532, endOfStream: false
+wasm log: OnHttpRequestBody called. BodySize: 933343, totalRequestBodyReadSize: 114532, endOfStream: true
+wasm log: read chunk size: 818811
+wasm log: pattern found in chunk: 2
+wasm log: local 403 response sent
+```

examples/http_body_chunk/envoy.yaml

@@ -0,0 +1,66 @@
+static_resources:
+  listeners:
+    - name: main
+      address:
+        socket_address:
+          address: 0.0.0.0
+          port_value: 18000
+      filter_chains:
+        - filters:
+            - name: envoy.http_connection_manager
+              typed_config:
+                "@type": type.googleapis.com/envoy.extensions.filters.network.http_connection_manager.v3.HttpConnectionManager
+                stat_prefix: ingress_http
+                codec_type: auto
+                route_config:
+                  name: admin
+                  virtual_hosts:
+                    - name: admin
+                      domains:
+                        - "*"
+                      routes:
+                        - match:
+                            prefix: "/"
+                          route:
+                            cluster: admin
+                http_filters:
+                  - name: envoy.filters.http.wasm
+                    typed_config:
+                      "@type": type.googleapis.com/udpa.type.v1.TypedStruct
+                      type_url: type.googleapis.com/envoy.extensions.filters.http.wasm.v3.Wasm
+                      value:
+                        config:
+                          configuration:
+                            "@type": type.googleapis.com/google.protobuf.StringValue
+                            value: "body-set"
+                          vm_config:
+                            runtime: "envoy.wasm.runtime.v8"
+                            code:
+                              local:
+                                filename: "./examples/http_body_chunk/main.wasm"
+                  - name: envoy.filters.http.router
+                    typed_config:
+                      "@type": type.googleapis.com/envoy.extensions.filters.http.router.v3.Router
+
+  clusters:
+    - name: admin
+      connect_timeout: 5000s
+      type: strict_dns
+      lb_policy: round_robin
+      load_assignment:
+        cluster_name: admin
+        endpoints:
+          - lb_endpoints:
+              - endpoint:
+                  address:
+                    socket_address:
+                      address: 0.0.0.0
+                      port_value: 8001
+
+
+admin:
+  access_log_path: "/dev/null"
+  address:
+    socket_address:
+      address: 0.0.0.0
+      port_value: 8001

examples/http_body_chunk/go.mod

@@ -0,0 +1,17 @@
+module github.com/tetratelabs/proxy-wasm-go-sdk/examples/http_body_chunk
+
+go 1.19
+
+replace github.com/tetratelabs/proxy-wasm-go-sdk => ../..
+
+require (
+	github.com/stretchr/testify v1.8.2
+	github.com/tetratelabs/proxy-wasm-go-sdk v0.0.0-00010101000000-000000000000
+)
+
+require (
+	github.com/davecgh/go-spew v1.1.1 // indirect
+	github.com/pmezard/go-difflib v1.0.0 // indirect
+	github.com/tetratelabs/wazero v1.0.1 // indirect
+	gopkg.in/yaml.v3 v3.0.1 // indirect
+)

examples/http_body_chunk/go.sum

@@ -0,0 +1,19 @@
+github.com/davecgh/go-spew v1.1.0/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
+github.com/davecgh/go-spew v1.1.1 h1:vj9j/u1bqnvCEfJOwUhtlOARqs3+rkHYY13jYWTU97c=
+github.com/davecgh/go-spew v1.1.1/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
+github.com/pmezard/go-difflib v1.0.0 h1:4DBwDE0NGyQoBHbLQYPwSUPoCMWR5BEzIk/f1lZbAQM=
+github.com/pmezard/go-difflib v1.0.0/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZNVY4sRDYZ/4=
+github.com/stretchr/objx v0.1.0/go.mod h1:HFkY916IF+rwdDfMAkV7OtwuqBVzrE8GR6GFx+wExME=
+github.com/stretchr/objx v0.4.0/go.mod h1:YvHI0jy2hoMjB+UWwv71VJQ9isScKT/TqJzVSSt89Yw=
+github.com/stretchr/objx v0.5.0/go.mod h1:Yh+to48EsGEfYuaHDzXPcE3xhTkx73EhmCGUpEOglKo=
+github.com/stretchr/testify v1.7.1/go.mod h1:6Fq8oRcR53rry900zMqJjRRixrwX3KX962/h/Wwjteg=
+github.com/stretchr/testify v1.8.0/go.mod h1:yNjHg4UonilssWZ8iaSj1OCr/vHnekPRkoO+kdMU+MU=
+github.com/stretchr/testify v1.8.2 h1:+h33VjcLVPDHtOdpUCuF+7gSuG3yGIftsP1YvFihtJ8=
+github.com/stretchr/testify v1.8.2/go.mod h1:w2LPCIKwWwSfY2zedu0+kehJoqGctiVI29o6fzry7u4=
+github.com/tetratelabs/wazero v1.0.1 h1:xyWBoGyMjYekG3mEQ/W7xm9E05S89kJ/at696d/9yuc=
+github.com/tetratelabs/wazero v1.0.1/go.mod h1:wYx2gNRg8/WihJfSDxA1TIL8H+GkfLYm+bIfbblu9VQ=
+gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405 h1:yhCVgyC4o1eVCa2tZl7eS0r+SDo693bJlVdllGtEeKM=
+gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
+gopkg.in/yaml.v3 v3.0.0-20200313102051-9f266ea9e77c/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=
+gopkg.in/yaml.v3 v3.0.1 h1:fxVm/GzAzEWqLHuvctI91KS9hhNmmWOoWu0XTYJS7CA=
+gopkg.in/yaml.v3 v3.0.1/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=

examples/http_body_chunk/main.go

@@ -0,0 +1,108 @@
+// Copyright 2020-2021 Tetrate
+//
+// 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.
+
+package main
+
+import (
+	"fmt"
+	"strings"
+
+	"github.com/tetratelabs/proxy-wasm-go-sdk/proxywasm"
+	"github.com/tetratelabs/proxy-wasm-go-sdk/proxywasm/types"
+)
+
+func main() {
+	proxywasm.SetVMContext(&vmContext{})
+}
+
+type vmContext struct {
+	// Embed the default VM context here,
+	// so that we don't need to reimplement all the methods.
+	types.DefaultVMContext
+}
+
+// Override types.DefaultVMContext.
+func (*vmContext) NewPluginContext(contextID uint32) types.PluginContext {
+	return &pluginContext{}
+}
+
+type pluginContext struct {
+	// Embed the default plugin context here,
+	// so that we don't need to reimplement all the methods.
+	types.DefaultPluginContext
+}
+
+// Override types.DefaultPluginContext.
+func (ctx *pluginContext) NewHttpContext(contextID uint32) types.HttpContext {
+	return &setBodyContext{}
+}
+
+// Override types.DefaultPluginContext.
+func (ctx *pluginContext) OnPluginStart(pluginConfigurationSize int) types.OnPluginStartStatus {
+	return types.OnPluginStartStatusOK
+}
+
+type setBodyContext struct {
+	// Embed the default root http context here,
+	// so that we don't need to reimplement all the methods.
+	types.DefaultHttpContext
+	totalRequestBodyReadSize int
+	receivedChunks           int
+}
+
+// Override types.DefaultHttpContext.
+func (ctx *setBodyContext) OnHttpRequestBody(bodySize int, endOfStream bool) types.Action {
+	proxywasm.LogInfof("OnHttpRequestBody called. BodySize: %d, totalRequestBodyReadSize: %d, endOfStream: %v", bodySize, ctx.totalRequestBodyReadSize, endOfStream)
+
+	// If some data has been received, we read it.
+	// Reading the body chunk by chunk, bodySize is the size of the current chunk, not the total size of the body.
+	chunkSize := bodySize - ctx.totalRequestBodyReadSize
+	if chunkSize > 0 {
+		ctx.receivedChunks++
+		chunk, err := proxywasm.GetHttpRequestBody(ctx.totalRequestBodyReadSize, chunkSize)
+		if err != nil {
+			proxywasm.LogCriticalf("failed to get request body: %v", err)
+			return types.ActionContinue
+		}
+		proxywasm.LogInfof("read chunk size: %d", len(chunk))
+		if len(chunk) != chunkSize {
+			proxywasm.LogErrorf("read data does not match the expected size: %d != %d", len(chunk), chunkSize)
+		}
+		ctx.totalRequestBodyReadSize += len(chunk)
+		if strings.Contains(string(chunk), "pattern") {
+			patternFound := fmt.Sprintf("pattern found in chunk: %d", ctx.receivedChunks)
+			proxywasm.LogInfo(patternFound)
+			if err := proxywasm.SendHttpResponse(403, [][2]string{
+				{"powered-by", "proxy-wasm-go-sdk"},
+			}, []byte(patternFound), -1); err != nil {
+				proxywasm.LogCriticalf("failed to send local response: %v", err)
+				proxywasm.ResumeHttpRequest()
+			} else {
+				proxywasm.LogInfo("local 403 response sent")
+			}
+			return types.ActionPause
+		}
+	}
+
+	if !endOfStream {
+		// Wait until we see the entire body before sending the request upstream.
+		return types.ActionPause
+	}
+	// When endOfStream is true, we have received the entire body. We expect the total size is equal to the sum of the sizes of the chunks.
+	if ctx.totalRequestBodyReadSize != bodySize {
+		proxywasm.LogErrorf("read data does not match the expected total size: %d != %d", ctx.totalRequestBodyReadSize, bodySize)
+	}
+	proxywasm.LogInfof("pattern not found")
+	return types.ActionContinue
+}