feat: add experimental opentelemetry exporter (#42)

Signed-off-by: Joonas Bergius <[email protected]>

x/wasitel/README.md

@@ -0,0 +1,16 @@
+# OpenTelemetry Exporter for WebAssembly Components
+
+> [!IMPORTANT]  
+> This requires TinyGo `0.35.0` (current `dev` branch) in order to compile.
+
+`wasitel` provides a `wasi:http`-based OpenTelemetry Go exporter implementation.
+
+## Examples:
+
+To be added.
+
+### Acknowledgements
+
+The `wasiteltrace/internal/convert` code has been adapted from [`opentelemetry-go`](https://github.com/open-telemetry/opentelemetry-go)'s internal packages, please see the code itself for the upstream soure references.
+
+The `wasiteltrace/internal/types` code has been adapted from [`opentelemetry-proto-go`](https://github.com/open-telemetry/opentelemetry-proto-go)'s generated protobufs, please see the code itself for the upstream source references.

x/wasitel/go.mod

@@ -0,0 +1,21 @@
+module go.wasmcloud.dev/component/x/wasitel
+
+go 1.23.2
+
+require (
+	go.opentelemetry.io/otel v1.31.0
+	go.opentelemetry.io/otel/sdk v1.31.0
+	go.opentelemetry.io/otel/trace v1.31.0
+	go.wasmcloud.dev/component v0.0.4
+)
+
+require (
+	github.com/go-logr/logr v1.4.2 // indirect
+	github.com/go-logr/stdr v1.2.2 // indirect
+	github.com/google/uuid v1.6.0 // indirect
+	go.bytecodealliance.org v0.4.0 // indirect
+	go.opentelemetry.io/otel/metric v1.31.0 // indirect
+	golang.org/x/sys v0.26.0 // indirect
+)
+
+replace go.wasmcloud.dev/component => ../../

x/wasitel/go.sum

@@ -0,0 +1,29 @@
+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/go-logr/logr v1.2.2/go.mod h1:jdQByPbusPIv2/zmleS9BjJVeZ6kBagPoEUsqbVz/1A=
+github.com/go-logr/logr v1.4.2 h1:6pFjapn8bFcIbiKo3XT4j/BhANplGihG6tvd+8rYgrY=
+github.com/go-logr/logr v1.4.2/go.mod h1:9T104GzyrTigFIr8wt5mBrctHMim0Nb2HLGrmQ40KvY=
+github.com/go-logr/stdr v1.2.2 h1:hSWxHoqTgW2S2qGc0LTAI563KZ5YKYRhT3MFKZMbjag=
+github.com/go-logr/stdr v1.2.2/go.mod h1:mMo/vtBO5dYbehREoey6XUKy/eSumjCCveDpRre4VKE=
+github.com/google/go-cmp v0.6.0 h1:ofyhxvXcZhMsU5ulbFiLKl/XBFqE1GSq7atu8tAmTRI=
+github.com/google/go-cmp v0.6.0/go.mod h1:17dUlkBOakJ0+DkrSSNjCkIjxS6bF9zb3elmeNGIjoY=
+github.com/google/uuid v1.6.0 h1:NIvaJDMOsjHA8n1jAhLSgzrAzy1Hgr+hNrb57e+94F0=
+github.com/google/uuid v1.6.0/go.mod h1:TIyPZe4MgqvfeYDBFedMoGGpEw/LqOeaOT+nhxU+yHo=
+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/testify v1.9.0 h1:HtqpIVDClZ4nwg75+f6Lvsy/wHu+3BoSGCbBAcpTsTg=
+github.com/stretchr/testify v1.9.0/go.mod h1:r2ic/lqez/lEtzL7wO/rwa5dbSLXVDPFyf8C91i36aY=
+go.bytecodealliance.org v0.4.0 h1:SRwgZIcXR54AmbJg9Y3AMgDlZlvD8dffteBYW+nCD3k=
+go.bytecodealliance.org v0.4.0/go.mod h1:hkdjfgQ/bFZYUucnm9cn0Q8/SHO3iT0rzskYlkV4Jy0=
+go.opentelemetry.io/otel v1.31.0 h1:NsJcKPIW0D0H3NgzPDHmo0WW6SptzPdqg/L1zsIm2hY=
+go.opentelemetry.io/otel v1.31.0/go.mod h1:O0C14Yl9FgkjqcCZAsE053C13OaddMYr/hz6clDkEJE=
+go.opentelemetry.io/otel/metric v1.31.0 h1:FSErL0ATQAmYHUIzSezZibnyVlft1ybhy4ozRPcF2fE=
+go.opentelemetry.io/otel/metric v1.31.0/go.mod h1:C3dEloVbLuYoX41KpmAhOqNriGbA+qqH6PQ5E5mUfnY=
+go.opentelemetry.io/otel/sdk v1.31.0 h1:xLY3abVHYZ5HSfOg3l2E5LUj2Cwva5Y7yGxnSW9H5Gk=
+go.opentelemetry.io/otel/sdk v1.31.0/go.mod h1:TfRbMdhvxIIr/B2N2LQW2S5v9m3gOQ/08KsbbO5BPT0=
+go.opentelemetry.io/otel/trace v1.31.0 h1:ffjsj1aRouKewfr85U2aGagJ46+MvodynlQ1HYdmJys=
+go.opentelemetry.io/otel/trace v1.31.0/go.mod h1:TXZkRk7SM2ZQLtR6eoAWQFIHPvzQ06FJAsO1tJg480A=
+golang.org/x/sys v0.26.0 h1:KHjCJyddX0LoSTb3J+vWpupP9p0oznkqVk/IfjymZbo=
+golang.org/x/sys v0.26.0/go.mod h1:/VUhepiaJMQUp4+oa/7Zr1D23ma6VTLIYjOOTFZPUcA=
+gopkg.in/yaml.v3 v3.0.1 h1:fxVm/GzAzEWqLHuvctI91KS9hhNmmWOoWu0XTYJS7CA=
+gopkg.in/yaml.v3 v3.0.1/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=

x/wasitel/wasiteltrace/client.go

@@ -0,0 +1,72 @@
+package wasiteltrace
+
+import (
+	"bytes"
+	"context"
+	"encoding/json"
+	"fmt"
+	"net/http"
+	"net/url"
+
+	"go.wasmcloud.dev/component/net/wasihttp"
+	"go.wasmcloud.dev/component/x/wasitel/wasiteltrace/internal/types"
+)
+
+type client struct {
+	config     config
+	httpClient *http.Client
+}
+
+func newClient(opts ...Option) *client {
+	cfg := newConfig(opts...)
+
+	wasiTransport := &wasihttp.Transport{}
+	httpClient := &http.Client{Transport: wasiTransport}
+
+	return &client{
+		config:     cfg,
+		httpClient: httpClient,
+	}
+}
+
+func (c *client) UploadTraces(ctx context.Context, spans []*types.ResourceSpans) error {
+	if len(spans) == 0 {
+		return nil
+	}
+
+	export := &types.ExportTraceServiceRequest{
+		ResourceSpans: spans,
+	}
+
+	body, err := json.Marshal(export)
+	if err != nil {
+		return fmt.Errorf("failed to serialize export request to JSON: %w", err)
+	}
+
+	u := c.getUrl()
+	req, err := http.NewRequest(http.MethodPost, u.String(), bytes.NewBuffer(body))
+	if err != nil {
+		return fmt.Errorf("failed to create request to %q: %w", u.String(), err)
+	}
+	req.Header.Set("Content-Type", "application/json")
+
+	_, err = c.httpClient.Do(req)
+	if err != nil {
+		return fmt.Errorf("failed to request %q: %w", u.String(), err)
+	}
+
+	return nil
+}
+
+func (c *client) getUrl() url.URL {
+	scheme := "http"
+	if !c.config.Insecure {
+		scheme = "https"
+	}
+	u := url.URL{
+		Scheme: scheme,
+		Host:   c.config.Endpoint,
+		Path:   c.config.Path,
+	}
+	return u
+}

x/wasitel/wasiteltrace/config.go

@@ -0,0 +1,74 @@
+package wasiteltrace
+
+import (
+	"fmt"
+	"net/url"
+)
+
+const (
+	// DefaultPort is the default HTTP port of the collector.
+	DefaultPort uint16 = 4318
+	// DefaultHost is the host address the client will attempt
+	// connect to if no collector address is provided.
+	DefaultHost string = "localhost"
+	// DefaultPath is a default URL path for endpoint that receives spans.
+	DefaultPath string = "/v1/traces"
+)
+
+type config struct {
+	Endpoint string
+	Insecure bool
+	Path     string
+}
+
+func newConfig(opts ...Option) config {
+	cfg := config{
+		Insecure: true,
+		Endpoint: fmt.Sprintf("%s:%d", DefaultHost, DefaultPort),
+		Path:     DefaultPath,
+	}
+	for _, opt := range opts {
+		cfg = opt.apply(cfg)
+	}
+	return cfg
+}
+
+type Option interface {
+	apply(config) config
+}
+
+func newWrappedOption(fn func(config) config) Option {
+	return &wrappedOption{fn: fn}
+}
+
+type wrappedOption struct {
+	fn func(config) config
+}
+
+func (o *wrappedOption) apply(cfg config) config {
+	return o.fn(cfg)
+}
+
+func WithEndpoint(endpoint string) Option {
+	return newWrappedOption(func(cfg config) config {
+		cfg.Endpoint = endpoint
+		return cfg
+	})
+}
+
+func WithEndpointURL(eu string) Option {
+	return newWrappedOption(func(cfg config) config {
+		u, err := url.Parse(eu)
+		if err != nil {
+			return cfg
+		}
+
+		cfg.Endpoint = u.Host
+		cfg.Path = u.Path
+		if u.Scheme != "https" {
+			cfg.Insecure = true
+		}
+
+		return cfg
+	})
+}

x/wasitel/wasiteltrace/exporter.go

@@ -0,0 +1,71 @@
+package wasiteltrace
+
+import (
+	"context"
+	"fmt"
+	"sync"
+
+	"go.opentelemetry.io/otel/sdk/trace"
+	tracesdk "go.opentelemetry.io/otel/sdk/trace"
+	"go.wasmcloud.dev/component/x/wasitel/wasiteltrace/internal/convert"
+)
+
+func New(opts ...Option) (*Exporter, error) {
+	client := newClient(opts...)
+	return &Exporter{
+		client: client,
+	}, nil
+}
+
+var _ tracesdk.SpanExporter = (*Exporter)(nil)
+
+type Exporter struct {
+	client    *client
+	stopped   bool
+	stoppedMu sync.RWMutex
+}
+
+func (e *Exporter) ExportSpans(ctx context.Context, spans []trace.ReadOnlySpan) error {
+	err := ctx.Err()
+	if err != nil {
+		return err
+	}
+
+	// Check whether the exporter has been told to Shutdown
+	e.stoppedMu.RLock()
+	stopped := e.stopped
+	e.stoppedMu.RUnlock()
+	if stopped {
+		return nil
+	}
+
+	// Check if there's nothing to export
+	converted := convert.ResourceSpans(spans)
+	if len(converted) == 0 {
+		return nil
+	}
+
+	err = e.client.UploadTraces(ctx, converted)
+	if err != nil {
+		return fmt.Errorf("failed to export spans: %w", err)
+	}
+	return nil
+}
+
+// Shutdown is called to stop the exporter, it performs no action.
+func (e *Exporter) Shutdown(ctx context.Context) error {
+	e.stoppedMu.Lock()
+	e.stopped = true
+	e.stoppedMu.Unlock()
+
+	return nil
+}
+
+// MarshalLog is the marshaling function used by the logging system to represent this Exporter.
+func (e *Exporter) MarshalLog() interface{} {
+	return struct {
+		Type string
+	}{
+		Type: "wasiteltrace",
+	}
+}