Add entrypoints for Plugin, Http, Tcp contexts (#6)

* Add entrypoints for Plugin, Http, Tcp contexts

Fixes #5

Signed-off-by: Matt Leon <[email protected]>

* Address PR comments

Signed-off-by: Matt Leon <[email protected]>

---------

Signed-off-by: Matt Leon <[email protected]>

Author: leonm1

README.md

@@ -59,20 +59,20 @@ import (
 
 func main() {}
 func init() {
-    proxywasm.SetVMContext(&vmContext{})
+    // Plugin authors can use any one of four entrypoints, such as
+    // `proxywasm.SetVMContext`, `proxywasm.SetPluginContext`, or
+    // `proxywasm.SetTcpContext`.
+    proxywasm.SetHttpContext(func(contextID uint32) types.HttpContext {
+      return &httpContext{}
+    })
 }
-
-type vmContext struct {
-    types.DefaultVMContext
-}
-func (*vmContext) NewPluginContext(contextID uint32) types.PluginContext {
-    return &pluginContext{}
+type httpContext struct {
+    types.DefaultHttpContext
 }
-
-type pluginContext struct {
-    types.DefaultPluginContext
+func (*httpContext) OnHttpRequestHeaders(numHeaders int, endOfStream bool) types.Action  {
+    proxywasm.LogInfo("Hello, world!")
+    return types.ActionContinue
 }
-// pluginContext should implement OnPluginStart, NewHttpContext, NewTcpContext, etc
 ```
 
 Compile the plugin as follows:

examples/helloworld/main.go

@@ -26,19 +26,9 @@ const tickMilliseconds uint32 = 1000
 
 func main() {}
 func init() {
-	proxywasm.SetVMContext(&vmContext{})
-}
-
-// vmContext implements types.VMContext.
-type vmContext struct {
-	// Embed the default VM context here,
-	// so that we don't need to reimplement all the methods.
-	types.DefaultVMContext
-}
-
-// NewPluginContext implements types.VMContext.
-func (*vmContext) NewPluginContext(contextID uint32) types.PluginContext {
-	return &helloWorld{}
+	proxywasm.SetPluginContext(func(contextID uint32) types.PluginContext {
+		return &helloWorld{}
+	})
 }
 
 // helloWorld implements types.PluginContext.

examples/helloworld/main_test.go

@@ -14,8 +14,8 @@ import (
 )
 
 func TestHelloWorld_OnTick(t *testing.T) {
-	vmTest(t, func(t *testing.T, vm types.VMContext) {
-		opt := proxytest.NewEmulatorOption().WithVMContext(vm)
+	vmTest(t, func(t *testing.T, pc types.PluginContextFactory) {
+		opt := proxytest.NewEmulatorOption().WithPluginContext(pc)
 		host, reset := proxytest.NewHostEmulator(opt)
 		defer reset()
 
@@ -33,8 +33,8 @@ func TestHelloWorld_OnTick(t *testing.T) {
 }
 
 func TestHelloWorld_OnPluginStart(t *testing.T) {
-	vmTest(t, func(t *testing.T, vm types.VMContext) {
-		opt := proxytest.NewEmulatorOption().WithVMContext(vm)
+	vmTest(t, func(t *testing.T, pc types.PluginContextFactory) {
+		opt := proxytest.NewEmulatorOption().WithPluginContext(pc)
 		host, reset := proxytest.NewHostEmulator(opt)
 		defer reset()
 
@@ -48,14 +48,15 @@ func TestHelloWorld_OnPluginStart(t *testing.T) {
 	})
 }
 
-// vmTest executes f twice, once with a types.VMContext that executes plugin code directly
-// in the host, and again by executing the plugin code within the compiled main.wasm binary.
-// Execution with main.wasm will be skipped if the file cannot be found.
-func vmTest(t *testing.T, f func(*testing.T, types.VMContext)) {
+// vmTest executes f twice, once with a types.PluginContextFactory that
+// executes plugin code directly in the host, and again by executing the plugin
+// code within the compiled main.wasm binary. Execution with main.wasm will be
+// skipped if the file cannot be found.
+func vmTest(t *testing.T, f func(*testing.T, types.PluginContextFactory)) {
 	t.Helper()
 
 	t.Run("go", func(t *testing.T) {
-		f(t, &vmContext{})
+		f(t, func(uint32) types.PluginContext { return &helloWorld{} })
 	})
 
 	t.Run("wasm", func(t *testing.T) {
@@ -66,6 +67,6 @@ func vmTest(t *testing.T, f func(*testing.T, types.VMContext)) {
 		v, err := proxytest.NewWasmVMContext(wasm)
 		require.NoError(t, err)
 		defer v.Close()
-		f(t, v)
+		f(t, v.NewPluginContext)
 	})
 }

examples/properties/main.go

@@ -21,30 +21,9 @@ import (
 
 func main() {}
 func init() {
-	proxywasm.SetVMContext(&vmContext{})
-}
-
-// vmContext implements types.VMContext.
-type vmContext struct {
-	// Embed the default VM context here,
-	// so that we don't need to reimplement all the methods.
-	types.DefaultVMContext
-}
-
-// NewPluginContext implements types.VMContext.
-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
-}
-
-// NewHttpContext implements types.PluginContext.
-func (*pluginContext) NewHttpContext(contextID uint32) types.HttpContext {
-	return &properties{contextID: contextID}
+	proxywasm.SetHttpContext(func(contextID uint32) types.HttpContext {
+		return &properties{contextID: contextID}
+	})
 }
 
 // properties implements types.HttpContext.

examples/properties/main_test.go

@@ -15,8 +15,8 @@ import (
 )
 
 func TestProperties_OnHttpRequestHeaders(t *testing.T) {
-	vmTest(t, func(t *testing.T, vm types.VMContext) {
-		opt := proxytest.NewEmulatorOption().WithVMContext(vm)
+	vmTest(t, func(t *testing.T, h types.HttpContextFactory) {
+		opt := proxytest.NewEmulatorOption().WithHttpContext(h)
 		host, reset := proxytest.NewHostEmulator(opt)
 		defer reset()
 
@@ -87,14 +87,17 @@ func TestProperties_OnHttpRequestHeaders(t *testing.T) {
 	})
 }
 
-// vmTest executes f twice, once with a types.VMContext that executes plugin code directly
-// in the host, and again by executing the plugin code within the compiled main.wasm binary.
-// Execution with main.wasm will be skipped if the file cannot be found.
-func vmTest(t *testing.T, f func(*testing.T, types.VMContext)) {
+// vmTest executes f twice, once with a types.HttpContextFactory that executes
+// plugin code directly in the host, and again by executing the plugin code
+// within the compiled main.wasm binary. Execution with main.wasm will be
+// skipped if the file cannot be found.
+func vmTest(t *testing.T, f func(*testing.T, types.HttpContextFactory)) {
 	t.Helper()
 
 	t.Run("go", func(t *testing.T) {
-		f(t, &vmContext{})
+		f(t, func(contextID uint32) types.HttpContext {
+			return &properties{contextID: contextID}
+		})
 	})
 
 	t.Run("wasm", func(t *testing.T) {
@@ -103,8 +106,9 @@ func vmTest(t *testing.T, f func(*testing.T, types.VMContext)) {
 			t.Skip("wasm not found")
 		}
 		v, err := proxytest.NewWasmVMContext(wasm)
+		p := v.NewPluginContext(1)
 		require.NoError(t, err)
 		defer v.Close()
-		f(t, v)
+		f(t, p.NewHttpContext)
 	})
 }

proxywasm/entrypoint.go

@@ -19,9 +19,57 @@ import (
 	"github.com/proxy-wasm/proxy-wasm-go-sdk/proxywasm/types"
 )
 
-// SetVMContext is the entrypoint for setting up the entire Wasm VM.
-// Please make sure to call this entrypoint during "main()" function;
-// otherwise, the VM fails.
+// SetVMContext is one possible entrypoint for setting up the entire Wasm VM.
+//
+// Subsequent calls to any entrypoint overwrite previous calls to any
+// entrypoint. Be sure to call exactly one entrypoint during `init()`,
+// otherwise the VM fails.
 func SetVMContext(ctx types.VMContext) {
 	internal.SetVMContext(ctx)
 }
+
+// SetPluginContext is one possible entrypoint for setting up the Wasm VM.
+//
+// Subsequent calls to any entrypoint overwrite previous calls to any
+// entrypoint. Be sure to call exactly one entrypoint during `init()`,
+// otherwise the VM fails.
+//
+// Using SetPluginContext instead of SetVmContext is suitable iff the plugin
+// does not make use of the VM configuration provided during `VmContext`'s
+// `OnVmStart` call (plugin configuration data is still provided during
+// `PluginContext`'s `OnPluginStart` call).
+func SetPluginContext(newPluginContext func(contextID uint32) types.PluginContext) {
+	internal.SetPluginContext(newPluginContext)
+}
+
+// SetHttpContext is one possible entrypoint for setting up the Wasm VM. It
+// allows plugin authors to provide an Http context implementation without
+// writing a VmContext or PluginContext.
+//
+// Subsequent calls to any entrypoint overwrite previous calls to any
+// entrypoint. Be sure to call exactly one entrypoint during `init()`,
+// otherwise the VM fails.
+//
+// SetHttpContext is suitable for stateless plugins that share no state between
+// HTTP requests, do not process TCP streams, have no expensive shared setup
+// requiring execution during `OnPluginStart`, and do not access the plugin
+// configuration data.
+func SetHttpContext(newHttpContext func(contextID uint32) types.HttpContext) {
+	internal.SetHttpContext(newHttpContext)
+}
+
+// SetTcpContext is one possible entrypoint for setting up the Wasm VM. It
+// allows plugin authors to provide a TCP context implementation without
+// writing a VmContext or PluginContext.
+//
+// Subsequent calls to any entrypoint overwrite previous calls to any
+// entrypoint. Be sure to call exactly one entrypoint during `init()`,
+// otherwise the VM fails.
+//
+// SetTcpContext is suitable for stateless plugins that share no state between
+// TCP streams, do not process HTTP requests, have no expensive shared setup
+// requiring execution during `OnPluginStart`, and do not access the plugin
+// configuration data.
+func SetTcpContext(newTcpContext func(contextID uint32) types.TcpContext) {
+	internal.SetTcpContext(newTcpContext)
+}

proxywasm/internal/entrypoints.go

@@ -0,0 +1,72 @@
+// Copyright 2025 Google LLC
+//
+// 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 internal
+
+import "github.com/proxy-wasm/proxy-wasm-go-sdk/proxywasm/types"
+
+// elidedVmContext is registered when the plugin author uses a
+// SetPluginContext, SetHttpContext, or SetTcpContext entrypoint. It indicates
+// the author did not register a VmContext.
+//
+// elidedVmContext's primary responsibility is calling the author-provided (or
+// elided) thunk to create a new PluginContext.
+type elidedVmContext struct {
+	types.DefaultVMContext
+	newPluginContext types.PluginContextFactory
+}
+
+func (ctx *elidedVmContext) NewPluginContext(contextID uint32) types.PluginContext {
+	return ctx.newPluginContext(contextID)
+}
+
+// elidedPluginContext is registered when the plugin author uses the
+// SetHttpContext or SetTcpContext entrypoints. It indicates the author did not
+// register a VmContext or PluginContext.
+//
+// elidedVmContext's primary responsibility is calling the author-provided (or
+// elided) thunk to create a new HttpContext or TcpContext.
+type elidedPluginContext struct {
+	types.DefaultPluginContext
+	newHttpContext types.HttpContextFactory
+	newTcpContext  types.TcpContextFactory
+}
+
+func (ctx *elidedPluginContext) NewHttpContext(contextID uint32) types.HttpContext {
+	return ctx.newHttpContext(contextID)
+}
+
+func (ctx *elidedPluginContext) NewTcpContext(contextID uint32) types.TcpContext {
+	return ctx.newTcpContext(contextID)
+}
+
+func SetPluginContext(newPluginContext types.PluginContextFactory) {
+	SetVMContext(&elidedVmContext{newPluginContext: newPluginContext})
+}
+
+func SetHttpContext(newHttpContext types.HttpContextFactory) {
+	SetVMContext(&elidedVmContext{
+		newPluginContext: func(uint32) types.PluginContext {
+			return &elidedPluginContext{newHttpContext: newHttpContext}
+		},
+	})
+}
+
+func SetTcpContext(newTcpContext types.TcpContextFactory) {
+	SetVMContext(&elidedVmContext{
+		newPluginContext: func(uint32) types.PluginContext {
+			return &elidedPluginContext{newTcpContext: newTcpContext}
+		},
+	})
+}