feat: add support for exporting metrics via wasitelmetrics.Exporter

x/wasitel/go.mod

@@ -3,9 +3,10 @@ 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.opentelemetry.io/otel v1.32.0
+	go.opentelemetry.io/otel/sdk v1.32.0
+	go.opentelemetry.io/otel/sdk/metric v1.32.0
+	go.opentelemetry.io/otel/trace v1.32.0
 	go.wasmcloud.dev/component v0.0.5
 )
 
@@ -14,8 +15,8 @@ require (
 	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
+	go.opentelemetry.io/otel/metric v1.32.0 // indirect
+	golang.org/x/sys v0.27.0 // indirect
 )
 
 replace go.wasmcloud.dev/component => ../../

x/wasitel/go.sum

@@ -15,15 +15,17 @@ github.com/stretchr/testify v1.9.0 h1:HtqpIVDClZ4nwg75+f6Lvsy/wHu+3BoSGCbBAcpTsT
 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=
+go.opentelemetry.io/otel v1.32.0 h1:WnBN+Xjcteh0zdk01SVqV55d/m62NJLJdIyb4y/WO5U=
+go.opentelemetry.io/otel v1.32.0/go.mod h1:00DCVSB0RQcnzlwyTfqtxSm+DRr9hpYrHjNGiBHVQIg=
+go.opentelemetry.io/otel/metric v1.32.0 h1:xV2umtmNcThh2/a/aCP+h64Xx5wsj8qqnkYZktzNa0M=
+go.opentelemetry.io/otel/metric v1.32.0/go.mod h1:jH7CIbbK6SH2V2wE16W05BHCtIDzauciCRLoc/SyMv8=
+go.opentelemetry.io/otel/sdk v1.32.0 h1:RNxepc9vK59A8XsgZQouW8ue8Gkb4jpWtJm9ge5lEG4=
+go.opentelemetry.io/otel/sdk v1.32.0/go.mod h1:LqgegDBjKMmb2GC6/PrTnteJG39I8/vJCAP9LlJXEjU=
+go.opentelemetry.io/otel/sdk/metric v1.32.0 h1:rZvFnvmvawYb0alrYkjraqJq0Z4ZUJAiyYCU9snn1CU=
+go.opentelemetry.io/otel/sdk/metric v1.32.0/go.mod h1:PWeZlq0zt9YkYAp3gjKZ0eicRYvOh1Gd+X99x6GHpCQ=
+go.opentelemetry.io/otel/trace v1.32.0 h1:WIC9mYrXf8TmY/EXuULKc8hR17vE+Hjv2cssQDe03fM=
+go.opentelemetry.io/otel/trace v1.32.0/go.mod h1:+i4rkvCraA+tG6AzwloGaCtkx53Fa+L+V8e9a7YvhT8=
+golang.org/x/sys v0.27.0 h1:wBqf8DvsY9Y/2P8gAfPDEYNuS30J4lPHJxXSb/nJZ+s=
+golang.org/x/sys v0.27.0/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/wasitelmetric/client.go

@@ -0,0 +1,79 @@
+package wasitelmetric
+
+import (
+	"bytes"
+	"context"
+	"encoding/json"
+	"fmt"
+	"net/http"
+	"net/url"
+
+	"go.wasmcloud.dev/component/net/wasihttp"
+	"go.wasmcloud.dev/component/x/wasitel/wasitelmetric/internal/types"
+)
+
+type clienti interface {
+	UploadMetrics(context.Context, *types.ResourceMetrics) error
+	Shutdown(context.Context) error
+}
+
+func newClient(opts ...Option) *client {
+	cfg := newConfig(opts...)
+
+	wasiTransport := &wasihttp.Transport{}
+	httpClient := &http.Client{Transport: wasiTransport}
+
+	return &client{
+		config:     cfg,
+		httpClient: httpClient,
+	}
+}
+
+type client struct {
+	config     config
+	httpClient *http.Client
+}
+
+func (c *client) UploadMetrics(ctx context.Context, rm *types.ResourceMetrics) error {
+	export := &types.ExportMetricsServiceRequest{
+		ResourceMetrics: []*types.ResourceMetrics{rm},
+	}
+
+	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
+}
+
+// Shutdown shuts down the client, freeing all resources.
+func (c *client) Shutdown(ctx context.Context) error {
+	c.httpClient = nil
+	return ctx.Err()
+}
+
+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/wasitelmetric/config.go

@@ -0,0 +1,74 @@
+package wasitelmetric
+
+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 metrics.
+	DefaultPath string = "/v1/metrics"
+)
+
+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/wasitelmetric/exporter.go

@@ -0,0 +1,110 @@
+package wasitelmetric
+
+import (
+	"context"
+	"fmt"
+	"sync"
+
+	metric "go.opentelemetry.io/otel/sdk/metric"
+	"go.opentelemetry.io/otel/sdk/metric/metricdata"
+	"go.wasmcloud.dev/component/x/wasitel/wasitelmetric/internal/convert"
+)
+
+func New(opts ...Option) (*Exporter, error) {
+	client := newClient(opts...)
+	return &Exporter{
+		client: client,
+	}, nil
+}
+
+type Exporter struct {
+	client *client
+
+	temporalitySelector metric.TemporalitySelector
+	aggregationSelector metric.AggregationSelector
+
+	stopped   bool
+	stoppedMu sync.RWMutex
+}
+
+var _ metric.Exporter = (*Exporter)(nil)
+
+// Temporality returns the Temporality to use for an instrument kind.
+func (e *Exporter) Temporality(k metric.InstrumentKind) metricdata.Temporality {
+	return e.temporalitySelector(k)
+}
+
+// Aggregation returns the Aggregation to use for an instrument kind.
+func (e *Exporter) Aggregation(k metric.InstrumentKind) metric.Aggregation {
+	return e.aggregationSelector(k)
+}
+
+func (e *Exporter) Export(ctx context.Context, data *metricdata.ResourceMetrics) 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
+	}
+
+	metrics, err := convert.ResourceMetrics(data)
+	if err != nil {
+		return err
+	}
+
+	err = e.client.UploadMetrics(ctx, metrics)
+	if err != nil {
+		return err
+	}
+
+	return nil
+}
+
+// ForceFlush flushes any metric data held by an exporter.
+//
+// This method returns an error if called after Shutdown.
+// This method returns an error if the method is canceled by the passed context.
+//
+// This method is safe to call concurrently.
+func (e *Exporter) ForceFlush(ctx context.Context) error {
+	// Check whether the exporter has been told to Shutdown
+	e.stoppedMu.RLock()
+	stopped := e.stopped
+	e.stoppedMu.RUnlock()
+	if stopped {
+		return errShutdown
+	}
+	return ctx.Err()
+}
+
+var errShutdown = fmt.Errorf("Exporter is shutdown")
+
+// Shutdown flushes all metric data held by an exporter and releases any held
+// computational resources.
+//
+// This method returns an error if called after Shutdown.
+// This method returns an error if the method is canceled by the passed context.
+//
+// This method is safe to call concurrently.
+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: "wasitelmetric",
+	}
+}

x/wasitel/wasitelmetric/internal/convert/metrics.go

@@ -0,0 +1,10 @@
+package convert
+
+import (
+	"go.opentelemetry.io/otel/sdk/metric/metricdata"
+	"go.wasmcloud.dev/component/x/wasitel/wasitelmetric/internal/types"
+)
+
+func ResourceMetrics(data *metricdata.ResourceMetrics) (*types.ResourceMetrics, error) {
+	return nil, nil
+}

x/wasitel/wasitelmetric/internal/types/common.go

@@ -0,0 +1,66 @@
+// Original source: https://github.com/open-telemetry/opentelemetry-proto-go/blob/v1.3.1/slim/otlp/common/v1/common.pb.go
+package types
+
+// AnyValue is used to represent any type of attribute value. AnyValue may contain a
+// primitive value such as a string or integer or it may contain an arbitrary nested
+// object containing arrays, key-value lists and primitives.
+type AnyValue struct {
+	// The value is one of the listed fields. It is valid for all values to be unspecified
+	// in which case this AnyValue is considered to be "empty".
+	//
+	// Types that are assignable to Value:
+	//	*AnyValue_StringValue
+	//	*AnyValue_BoolValue
+	//	*AnyValue_IntValue
+	//	*AnyValue_DoubleValue
+	//	*AnyValue_ArrayValue
+	//	*AnyValue_KvlistValue
+	//	*AnyValue_BytesValue
+	StringValue string        `json:"stringValue,omitempty"`
+	BoolValue   bool          `json:"boolValue,omitempty"`
+	IntValue    int64         `json:"intValue,omitempty"`
+	DoubleValue float64       `json:"doubleValue,omitempty"`
+	ArrayValue  *ArrayValue   `json:"arrayValue,omitempty"`
+	KvlistValue *KeyValueList `json:"kvlistValue,omitempty"`
+	BytesValue  []byte        `json:"bytesValue,omitempty"`
+}
+
+// ArrayValue is a list of AnyValue messages. We need ArrayValue as a message
+// since oneof in AnyValue does not allow repeated fields.
+type ArrayValue struct {
+	// Array of values. The array may be empty (contain 0 elements).
+	Values []*AnyValue `json:"values,omitempty"`
+}
+
+// KeyValueList is a list of KeyValue messages. We need KeyValueList as a message
+// since `oneof` in AnyValue does not allow repeated fields. Everywhere else where we need
+// a list of KeyValue messages (e.g. in Span) we use `repeated KeyValue` directly to
+// avoid unnecessary extra wrapping (which slows down the protocol). The 2 approaches
+// are semantically equivalent.
+type KeyValueList struct {
+	// A collection of key/value pairs of key-value pairs. The list may be empty (may
+	// contain 0 elements).
+	// The keys MUST be unique (it is not allowed to have more than one
+	// value with the same key).
+	Values []*KeyValue `json:"values,omitempty"`
+}
+
+// KeyValue is a key-value pair that is used to store Span attributes, Link
+// attributes, etc.
+type KeyValue struct {
+	Key   string    `json:"key,omitempty"`
+	Value *AnyValue `json:"value,omitempty"`
+}
+
+// InstrumentationScope is a message representing the instrumentation scope information
+// such as the fully qualified name and version.
+type InstrumentationScope struct {
+	// An empty instrumentation scope name means the name is unknown.
+	Name    string `json:"name,omitempty"`
+	Version string `json:"version,omitempty"`
+	// Additional attributes that describe the scope. [Optional].
+	// Attribute keys MUST be unique (it is not allowed to have more than one
+	// attribute with the same key).
+	Attributes             []*KeyValue `json:"attributes,omitempty"`
+	DroppedAttributesCount uint32      `json:"dropped_attributes_count,omitempty"`
+}