feature: Go net/http -> wasi:http Proxy

Signed-off-by: Lucas Fontes <lucas@cosmonic.com>

examples/http-server/.gitignore

@@ -0,0 +1,2 @@
+http-server
+/build

examples/http-server/README.md

@@ -0,0 +1,48 @@
+# http-server
+
+This example demonstrates how to forward requests to components exporting `wasi:http/incoming-handler`.
+
+It starts a http server listening on port 8080 containing 2 routes:
+
+- `/proxy`: Forwards the request to the component `http-component`
+- `/`: Serve the request directly from the provider
+
+# Internals
+
+Proxying uses a custom `http.RoundTripper` implementation that forwards requests to the component.
+In this example we forward to a single target ( `http-http_component` ).
+
+```go
+transport := wrpchttp.NewIncomingRoundTripper(wasmcloudprovider, wrpchttp.WithSingleTarget("http-http_component"))
+
+wasiIncomingClient := &http.Client{
+  Transport: transport,
+}
+
+wasiIncomingClient.Get("http://localhost:8080/proxy")
+```
+
+You can also provide a custom `Director` function to select the target based on the request.
+
+```go
+func director(r *http.Request) string {
+  if r.URL.Host == "api" {
+    return "http-api"
+  }
+  return "http-ui"
+})
+
+
+transport := wrpchttp.NewIncomingRoundTripper(wasmcloudprovider, wrpchttp.WithDirector(director))
+
+wasiIncomingClient := &http.Client{
+  Transport: transport,
+}
+
+// forward to http-api component
+wasiIncomingClient.Get("http://api/users")
+
+// forward to http-ui component
+wasiIncomingClient.Get("http://ui/index.html")
+wasiIncomingClient.Get("http://anyothername/index.html")
+```

examples/http-server/bindings/server.wrpc.go

@@ -0,0 +1,3 @@
+// Generated by `wit-bindgen-wrpc-go` 0.8.0. DO NOT EDIT!
+// server package contains wRPC bindings for `server` world
+package server

examples/http-server/bindings/wasi/clocks/monotonic_clock/bindings.wrpc.go

@@ -0,0 +1,286 @@
+// Generated by `wit-bindgen-wrpc-go` 0.8.0. DO NOT EDIT!
+package monotonic_clock
+
+import (
+	bytes "bytes"
+	context "context"
+	binary "encoding/binary"
+	errors "errors"
+	fmt "fmt"
+	wasi__io__poll "github.com/wasmCloud/provider-sdk-go/examples/http-server/bindings/wasi/io/poll"
+	io "io"
+	slog "log/slog"
+	utf8 "unicode/utf8"
+	wrpc "wrpc.io/go"
+)
+
+type Pollable = wasi__io__poll.Pollable
+
+// An instant in time, in nanoseconds. An instant is relative to an
+// unspecified initial value, and can only be compared to instances from
+// the same monotonic-clock.
+type Instant = uint64
+
+// A duration of time, in nanoseconds.
+type Duration = uint64
+
+// Read the current value of the clock.
+//
+// The clock is monotonic, therefore calling this function repeatedly will
+// produce a sequence of non-decreasing values.
+func Now(ctx__ context.Context, wrpc__ wrpc.Invoker) (r0__ uint64, err__ error) {
+	var w__ wrpc.IndexWriteCloser
+	var r__ wrpc.IndexReadCloser
+	w__, r__, err__ = wrpc__.Invoke(ctx__, "wasi:clocks/monotonic-clock@0.2.0", "now", nil)
+	if err__ != nil {
+		err__ = fmt.Errorf("failed to invoke `now`: %w", err__)
+		return
+	}
+	defer func() {
+		if err := r__.Close(); err != nil {
+			slog.ErrorContext(ctx__, "failed to close reader", "instance", "wasi:clocks/monotonic-clock@0.2.0", "name", "now", "err", err)
+		}
+	}()
+	if cErr__ := w__.Close(); cErr__ != nil {
+		slog.DebugContext(ctx__, "failed to close outgoing stream", "instance", "wasi:clocks/monotonic-clock@0.2.0", "name", "now", "err", cErr__)
+	}
+	r0__, err__ = func() (Instant, error) {
+		v, err := func(r io.ByteReader) (uint64, error) {
+			var x uint64
+			var s uint8
+			for i := 0; i < 10; i++ {
+				slog.Debug("reading u64 byte", "i", i)
+				b, err := r.ReadByte()
+				if err != nil {
+					if i > 0 && err == io.EOF {
+						err = io.ErrUnexpectedEOF
+					}
+					return x, fmt.Errorf("failed to read u64 byte: %w", err)
+				}
+				if s == 63 && b > 0x01 {
+					return x, errors.New("varint overflows a 64-bit integer")
+				}
+				if b < 0x80 {
+					return x | uint64(b)<<s, nil
+				}
+				x |= uint64(b&0x7f) << s
+				s += 7
+			}
+			return x, errors.New("varint overflows a 64-bit integer")
+		}(r__)
+		return (Instant)(v), err
+	}()
+
+	if err__ != nil {
+		err__ = fmt.Errorf("failed to read result 0: %w", err__)
+		return
+	}
+	return
+}
+
+// Query the resolution of the clock. Returns the duration of time
+// corresponding to a clock tick.
+func Resolution(ctx__ context.Context, wrpc__ wrpc.Invoker) (r0__ uint64, err__ error) {
+	var w__ wrpc.IndexWriteCloser
+	var r__ wrpc.IndexReadCloser
+	w__, r__, err__ = wrpc__.Invoke(ctx__, "wasi:clocks/monotonic-clock@0.2.0", "resolution", nil)
+	if err__ != nil {
+		err__ = fmt.Errorf("failed to invoke `resolution`: %w", err__)
+		return
+	}
+	defer func() {
+		if err := r__.Close(); err != nil {
+			slog.ErrorContext(ctx__, "failed to close reader", "instance", "wasi:clocks/monotonic-clock@0.2.0", "name", "resolution", "err", err)
+		}
+	}()
+	if cErr__ := w__.Close(); cErr__ != nil {
+		slog.DebugContext(ctx__, "failed to close outgoing stream", "instance", "wasi:clocks/monotonic-clock@0.2.0", "name", "resolution", "err", cErr__)
+	}
+	r0__, err__ = func() (Duration, error) {
+		v, err := func(r io.ByteReader) (uint64, error) {
+			var x uint64
+			var s uint8
+			for i := 0; i < 10; i++ {
+				slog.Debug("reading u64 byte", "i", i)
+				b, err := r.ReadByte()
+				if err != nil {
+					if i > 0 && err == io.EOF {
+						err = io.ErrUnexpectedEOF
+					}
+					return x, fmt.Errorf("failed to read u64 byte: %w", err)
+				}
+				if s == 63 && b > 0x01 {
+					return x, errors.New("varint overflows a 64-bit integer")
+				}
+				if b < 0x80 {
+					return x | uint64(b)<<s, nil
+				}
+				x |= uint64(b&0x7f) << s
+				s += 7
+			}
+			return x, errors.New("varint overflows a 64-bit integer")
+		}(r__)
+		return (Duration)(v), err
+	}()
+
+	if err__ != nil {
+		err__ = fmt.Errorf("failed to read result 0: %w", err__)
+		return
+	}
+	return
+}
+
+// Create a `pollable` which will resolve once the specified instant
+// occured.
+func SubscribeInstant(ctx__ context.Context, wrpc__ wrpc.Invoker, when uint64) (r0__ wrpc.Own[Pollable], err__ error) {
+	var buf__ bytes.Buffer
+	write0__, err__ := (func(wrpc.IndexWriter) error)(nil), func(v uint64, w io.Writer) (err error) {
+		b := make([]byte, binary.MaxVarintLen64)
+		i := binary.PutUvarint(b, uint64(v))
+		slog.Debug("writing u64")
+		_, err = w.Write(b[:i])
+		return err
+	}(when, &buf__)
+	if err__ != nil {
+		err__ = fmt.Errorf("failed to write `when` parameter: %w", err__)
+		return
+	}
+	if write0__ != nil {
+		err__ = errors.New("unexpected deferred write for synchronous `when` parameter")
+		return
+	}
+	var w__ wrpc.IndexWriteCloser
+	var r__ wrpc.IndexReadCloser
+	w__, r__, err__ = wrpc__.Invoke(ctx__, "wasi:clocks/monotonic-clock@0.2.0", "subscribe-instant", buf__.Bytes())
+	if err__ != nil {
+		err__ = fmt.Errorf("failed to invoke `subscribe-instant`: %w", err__)
+		return
+	}
+	defer func() {
+		if err := r__.Close(); err != nil {
+			slog.ErrorContext(ctx__, "failed to close reader", "instance", "wasi:clocks/monotonic-clock@0.2.0", "name", "subscribe-instant", "err", err)
+		}
+	}()
+	if cErr__ := w__.Close(); cErr__ != nil {
+		slog.DebugContext(ctx__, "failed to close outgoing stream", "instance", "wasi:clocks/monotonic-clock@0.2.0", "name", "subscribe-instant", "err", cErr__)
+	}
+	r0__, err__ = func(r interface {
+		io.ByteReader
+		io.Reader
+	}) (wrpc.Own[Pollable], error) {
+		var x uint32
+		var s uint
+		for i := 0; i < 5; i++ {
+			slog.Debug("reading owned resource ID length byte", "i", i)
+			b, err := r.ReadByte()
+			if err != nil {
+				if i > 0 && err == io.EOF {
+					err = io.ErrUnexpectedEOF
+				}
+				return "", fmt.Errorf("failed to read owned resource ID length byte: %w", err)
+			}
+			if b < 0x80 {
+				if i == 4 && b > 1 {
+					return "", errors.New("owned resource ID length overflows a 32-bit integer")
+				}
+				x = x | uint32(b)<<s
+				buf := make([]byte, x)
+				slog.Debug("reading owned resource ID bytes", "len", x)
+				_, err = r.Read(buf)
+				if err != nil {
+					return "", fmt.Errorf("failed to read owned resource ID bytes: %w", err)
+				}
+				if !utf8.Valid(buf) {
+					return "", errors.New("owned resource ID is not valid UTF-8")
+				}
+				return wrpc.Own[Pollable](buf), nil
+			}
+			x |= uint32(b&0x7f) << s
+			s += 7
+		}
+		return "", errors.New("owned resource ID length overflows a 32-bit integer")
+	}(r__)
+	if err__ != nil {
+		err__ = fmt.Errorf("failed to read result 0: %w", err__)
+		return
+	}
+	return
+}
+
+// Create a `pollable` which will resolve once the given duration has
+// elapsed, starting at the time at which this function was called.
+// occured.
+func SubscribeDuration(ctx__ context.Context, wrpc__ wrpc.Invoker, when uint64) (r0__ wrpc.Own[Pollable], err__ error) {
+	var buf__ bytes.Buffer
+	write0__, err__ := (func(wrpc.IndexWriter) error)(nil), func(v uint64, w io.Writer) (err error) {
+		b := make([]byte, binary.MaxVarintLen64)
+		i := binary.PutUvarint(b, uint64(v))
+		slog.Debug("writing u64")
+		_, err = w.Write(b[:i])
+		return err
+	}(when, &buf__)
+	if err__ != nil {
+		err__ = fmt.Errorf("failed to write `when` parameter: %w", err__)
+		return
+	}
+	if write0__ != nil {
+		err__ = errors.New("unexpected deferred write for synchronous `when` parameter")
+		return
+	}
+	var w__ wrpc.IndexWriteCloser
+	var r__ wrpc.IndexReadCloser
+	w__, r__, err__ = wrpc__.Invoke(ctx__, "wasi:clocks/monotonic-clock@0.2.0", "subscribe-duration", buf__.Bytes())
+	if err__ != nil {
+		err__ = fmt.Errorf("failed to invoke `subscribe-duration`: %w", err__)
+		return
+	}
+	defer func() {
+		if err := r__.Close(); err != nil {
+			slog.ErrorContext(ctx__, "failed to close reader", "instance", "wasi:clocks/monotonic-clock@0.2.0", "name", "subscribe-duration", "err", err)
+		}
+	}()
+	if cErr__ := w__.Close(); cErr__ != nil {
+		slog.DebugContext(ctx__, "failed to close outgoing stream", "instance", "wasi:clocks/monotonic-clock@0.2.0", "name", "subscribe-duration", "err", cErr__)
+	}
+	r0__, err__ = func(r interface {
+		io.ByteReader
+		io.Reader
+	}) (wrpc.Own[Pollable], error) {
+		var x uint32
+		var s uint
+		for i := 0; i < 5; i++ {
+			slog.Debug("reading owned resource ID length byte", "i", i)
+			b, err := r.ReadByte()
+			if err != nil {
+				if i > 0 && err == io.EOF {
+					err = io.ErrUnexpectedEOF
+				}
+				return "", fmt.Errorf("failed to read owned resource ID length byte: %w", err)
+			}
+			if b < 0x80 {
+				if i == 4 && b > 1 {
+					return "", errors.New("owned resource ID length overflows a 32-bit integer")
+				}
+				x = x | uint32(b)<<s
+				buf := make([]byte, x)
+				slog.Debug("reading owned resource ID bytes", "len", x)
+				_, err = r.Read(buf)
+				if err != nil {
+					return "", fmt.Errorf("failed to read owned resource ID bytes: %w", err)
+				}
+				if !utf8.Valid(buf) {
+					return "", errors.New("owned resource ID is not valid UTF-8")
+				}
+				return wrpc.Own[Pollable](buf), nil
+			}
+			x |= uint32(b&0x7f) << s
+			s += 7
+		}
+		return "", errors.New("owned resource ID length overflows a 32-bit integer")
+	}(r__)
+	if err__ != nil {
+		err__ = fmt.Errorf("failed to read result 0: %w", err__)
+		return
+	}
+	return
+}