build: move e2e dependencies into e2e/go.mod

Several packages are only used while running the e2e suite. These
packages are less important to update, as the they can not influence the
final executable that is part of the Ceph-CSI container-image.

By moving these dependencies out of the main Ceph-CSI go.mod, it is
easier to identify if a reported CVE affects Ceph-CSI, or only the
testing (like most of the Kubernetes CVEs).

Signed-off-by: Niels de Vos <ndevos@ibm.com>

e2e/vendor/go.opentelemetry.io/auto/sdk/internal/telemetry/attr.go

@@ -0,0 +1,58 @@
+// Copyright The OpenTelemetry Authors
+// SPDX-License-Identifier: Apache-2.0
+
+package telemetry
+
+// Attr is a key-value pair.
+type Attr struct {
+	Key   string `json:"key,omitempty"`
+	Value Value  `json:"value,omitempty"`
+}
+
+// String returns an Attr for a string value.
+func String(key, value string) Attr {
+	return Attr{key, StringValue(value)}
+}
+
+// Int64 returns an Attr for an int64 value.
+func Int64(key string, value int64) Attr {
+	return Attr{key, Int64Value(value)}
+}
+
+// Int returns an Attr for an int value.
+func Int(key string, value int) Attr {
+	return Int64(key, int64(value))
+}
+
+// Float64 returns an Attr for a float64 value.
+func Float64(key string, value float64) Attr {
+	return Attr{key, Float64Value(value)}
+}
+
+// Bool returns an Attr for a bool value.
+func Bool(key string, value bool) Attr {
+	return Attr{key, BoolValue(value)}
+}
+
+// Bytes returns an Attr for a []byte value.
+// The passed slice must not be changed after it is passed.
+func Bytes(key string, value []byte) Attr {
+	return Attr{key, BytesValue(value)}
+}
+
+// Slice returns an Attr for a []Value value.
+// The passed slice must not be changed after it is passed.
+func Slice(key string, value ...Value) Attr {
+	return Attr{key, SliceValue(value...)}
+}
+
+// Map returns an Attr for a map value.
+// The passed slice must not be changed after it is passed.
+func Map(key string, value ...Attr) Attr {
+	return Attr{key, MapValue(value...)}
+}
+
+// Equal returns if a is equal to b.
+func (a Attr) Equal(b Attr) bool {
+	return a.Key == b.Key && a.Value.Equal(b.Value)
+}

e2e/vendor/go.opentelemetry.io/auto/sdk/internal/telemetry/doc.go

@@ -0,0 +1,8 @@
+// Copyright The OpenTelemetry Authors
+// SPDX-License-Identifier: Apache-2.0
+
+/*
+Package telemetry provides a lightweight representations of OpenTelemetry
+telemetry that is compatible with the OTLP JSON protobuf encoding.
+*/
+package telemetry

e2e/vendor/go.opentelemetry.io/auto/sdk/internal/telemetry/id.go

@@ -0,0 +1,103 @@
+// Copyright The OpenTelemetry Authors
+// SPDX-License-Identifier: Apache-2.0
+
+package telemetry
+
+import (
+	"encoding/hex"
+	"errors"
+	"fmt"
+)
+
+const (
+	traceIDSize = 16
+	spanIDSize  = 8
+)
+
+// TraceID is a custom data type that is used for all trace IDs.
+type TraceID [traceIDSize]byte
+
+// String returns the hex string representation form of a TraceID.
+func (tid TraceID) String() string {
+	return hex.EncodeToString(tid[:])
+}
+
+// IsEmpty returns false if id contains at least one non-zero byte.
+func (tid TraceID) IsEmpty() bool {
+	return tid == [traceIDSize]byte{}
+}
+
+// MarshalJSON converts the trace ID into a hex string enclosed in quotes.
+func (tid TraceID) MarshalJSON() ([]byte, error) {
+	if tid.IsEmpty() {
+		return []byte(`""`), nil
+	}
+	return marshalJSON(tid[:])
+}
+
+// UnmarshalJSON inflates the trace ID from hex string, possibly enclosed in
+// quotes.
+func (tid *TraceID) UnmarshalJSON(data []byte) error {
+	*tid = [traceIDSize]byte{}
+	return unmarshalJSON(tid[:], data)
+}
+
+// SpanID is a custom data type that is used for all span IDs.
+type SpanID [spanIDSize]byte
+
+// String returns the hex string representation form of a SpanID.
+func (sid SpanID) String() string {
+	return hex.EncodeToString(sid[:])
+}
+
+// IsEmpty returns true if the span ID contains at least one non-zero byte.
+func (sid SpanID) IsEmpty() bool {
+	return sid == [spanIDSize]byte{}
+}
+
+// MarshalJSON converts span ID into a hex string enclosed in quotes.
+func (sid SpanID) MarshalJSON() ([]byte, error) {
+	if sid.IsEmpty() {
+		return []byte(`""`), nil
+	}
+	return marshalJSON(sid[:])
+}
+
+// UnmarshalJSON decodes span ID from hex string, possibly enclosed in quotes.
+func (sid *SpanID) UnmarshalJSON(data []byte) error {
+	*sid = [spanIDSize]byte{}
+	return unmarshalJSON(sid[:], data)
+}
+
+// marshalJSON converts id into a hex string enclosed in quotes.
+func marshalJSON(id []byte) ([]byte, error) {
+	// Plus 2 quote chars at the start and end.
+	hexLen := hex.EncodedLen(len(id)) + 2
+
+	b := make([]byte, hexLen)
+	hex.Encode(b[1:hexLen-1], id)
+	b[0], b[hexLen-1] = '"', '"'
+
+	return b, nil
+}
+
+// unmarshalJSON inflates trace id from hex string, possibly enclosed in quotes.
+func unmarshalJSON(dst []byte, src []byte) error {
+	if l := len(src); l >= 2 && src[0] == '"' && src[l-1] == '"' {
+		src = src[1 : l-1]
+	}
+	nLen := len(src)
+	if nLen == 0 {
+		return nil
+	}
+
+	if len(dst) != hex.DecodedLen(nLen) {
+		return errors.New("invalid length for ID")
+	}
+
+	_, err := hex.Decode(dst, src)
+	if err != nil {
+		return fmt.Errorf("cannot unmarshal ID from string '%s': %w", string(src), err)
+	}
+	return nil
+}

e2e/vendor/go.opentelemetry.io/auto/sdk/internal/telemetry/number.go

@@ -0,0 +1,67 @@
+// Copyright The OpenTelemetry Authors
+// SPDX-License-Identifier: Apache-2.0
+
+package telemetry
+
+import (
+	"encoding/json"
+	"strconv"
+)
+
+// protoInt64 represents the protobuf encoding of integers which can be either
+// strings or integers.
+type protoInt64 int64
+
+// Int64 returns the protoInt64 as an int64.
+func (i *protoInt64) Int64() int64 { return int64(*i) }
+
+// UnmarshalJSON decodes both strings and integers.
+func (i *protoInt64) UnmarshalJSON(data []byte) error {
+	if data[0] == '"' {
+		var str string
+		if err := json.Unmarshal(data, &str); err != nil {
+			return err
+		}
+		parsedInt, err := strconv.ParseInt(str, 10, 64)
+		if err != nil {
+			return err
+		}
+		*i = protoInt64(parsedInt)
+	} else {
+		var parsedInt int64
+		if err := json.Unmarshal(data, &parsedInt); err != nil {
+			return err
+		}
+		*i = protoInt64(parsedInt)
+	}
+	return nil
+}
+
+// protoUint64 represents the protobuf encoding of integers which can be either
+// strings or integers.
+type protoUint64 uint64
+
+// Int64 returns the protoUint64 as a uint64.
+func (i *protoUint64) Uint64() uint64 { return uint64(*i) }
+
+// UnmarshalJSON decodes both strings and integers.
+func (i *protoUint64) UnmarshalJSON(data []byte) error {
+	if data[0] == '"' {
+		var str string
+		if err := json.Unmarshal(data, &str); err != nil {
+			return err
+		}
+		parsedUint, err := strconv.ParseUint(str, 10, 64)
+		if err != nil {
+			return err
+		}
+		*i = protoUint64(parsedUint)
+	} else {
+		var parsedUint uint64
+		if err := json.Unmarshal(data, &parsedUint); err != nil {
+			return err
+		}
+		*i = protoUint64(parsedUint)
+	}
+	return nil
+}

e2e/vendor/go.opentelemetry.io/auto/sdk/internal/telemetry/resource.go

@@ -0,0 +1,66 @@
+// Copyright The OpenTelemetry Authors
+// SPDX-License-Identifier: Apache-2.0
+
+package telemetry
+
+import (
+	"bytes"
+	"encoding/json"
+	"errors"
+	"fmt"
+	"io"
+)
+
+// Resource information.
+type Resource struct {
+	// Attrs are the set of attributes that describe the resource. Attribute
+	// keys MUST be unique (it is not allowed to have more than one attribute
+	// with the same key).
+	Attrs []Attr `json:"attributes,omitempty"`
+	// DroppedAttrs is the number of dropped attributes. If the value
+	// is 0, then no attributes were dropped.
+	DroppedAttrs uint32 `json:"droppedAttributesCount,omitempty"`
+}
+
+// UnmarshalJSON decodes the OTLP formatted JSON contained in data into r.
+func (r *Resource) UnmarshalJSON(data []byte) error {
+	decoder := json.NewDecoder(bytes.NewReader(data))
+
+	t, err := decoder.Token()
+	if err != nil {
+		return err
+	}
+	if t != json.Delim('{') {
+		return errors.New("invalid Resource type")
+	}
+
+	for decoder.More() {
+		keyIface, err := decoder.Token()
+		if err != nil {
+			if errors.Is(err, io.EOF) {
+				// Empty.
+				return nil
+			}
+			return err
+		}
+
+		key, ok := keyIface.(string)
+		if !ok {
+			return fmt.Errorf("invalid Resource field: %#v", keyIface)
+		}
+
+		switch key {
+		case "attributes":
+			err = decoder.Decode(&r.Attrs)
+		case "droppedAttributesCount", "dropped_attributes_count":
+			err = decoder.Decode(&r.DroppedAttrs)
+		default:
+			// Skip unknown.
+		}
+
+		if err != nil {
+			return err
+		}
+	}
+	return nil
+}

e2e/vendor/go.opentelemetry.io/auto/sdk/internal/telemetry/scope.go

@@ -0,0 +1,67 @@
+// Copyright The OpenTelemetry Authors
+// SPDX-License-Identifier: Apache-2.0
+
+package telemetry
+
+import (
+	"bytes"
+	"encoding/json"
+	"errors"
+	"fmt"
+	"io"
+)
+
+// Scope is the identifying values of the instrumentation scope.
+type Scope struct {
+	Name         string `json:"name,omitempty"`
+	Version      string `json:"version,omitempty"`
+	Attrs        []Attr `json:"attributes,omitempty"`
+	DroppedAttrs uint32 `json:"droppedAttributesCount,omitempty"`
+}
+
+// UnmarshalJSON decodes the OTLP formatted JSON contained in data into r.
+func (s *Scope) UnmarshalJSON(data []byte) error {
+	decoder := json.NewDecoder(bytes.NewReader(data))
+
+	t, err := decoder.Token()
+	if err != nil {
+		return err
+	}
+	if t != json.Delim('{') {
+		return errors.New("invalid Scope type")
+	}
+
+	for decoder.More() {
+		keyIface, err := decoder.Token()
+		if err != nil {
+			if errors.Is(err, io.EOF) {
+				// Empty.
+				return nil
+			}
+			return err
+		}
+
+		key, ok := keyIface.(string)
+		if !ok {
+			return fmt.Errorf("invalid Scope field: %#v", keyIface)
+		}
+
+		switch key {
+		case "name":
+			err = decoder.Decode(&s.Name)
+		case "version":
+			err = decoder.Decode(&s.Version)
+		case "attributes":
+			err = decoder.Decode(&s.Attrs)
+		case "droppedAttributesCount", "dropped_attributes_count":
+			err = decoder.Decode(&s.DroppedAttrs)
+		default:
+			// Skip unknown.
+		}
+
+		if err != nil {
+			return err
+		}
+	}
+	return nil
+}

e2e/vendor/go.opentelemetry.io/auto/sdk/internal/telemetry/span.go

@@ -0,0 +1,456 @@
+// Copyright The OpenTelemetry Authors
+// SPDX-License-Identifier: Apache-2.0
+
+package telemetry
+
+import (
+	"bytes"
+	"encoding/hex"
+	"encoding/json"
+	"errors"
+	"fmt"
+	"io"
+	"time"
+)
+
+// A Span represents a single operation performed by a single component of the
+// system.
+type Span struct {
+	// A unique identifier for a trace. All spans from the same trace share
+	// the same `trace_id`. The ID is a 16-byte array. An ID with all zeroes OR
+	// of length other than 16 bytes is considered invalid (empty string in OTLP/JSON
+	// is zero-length and thus is also invalid).
+	//
+	// This field is required.
+	TraceID TraceID `json:"traceId,omitempty"`
+	// A unique identifier for a span within a trace, assigned when the span
+	// is created. The ID is an 8-byte array. An ID with all zeroes OR of length
+	// other than 8 bytes is considered invalid (empty string in OTLP/JSON
+	// is zero-length and thus is also invalid).
+	//
+	// This field is required.
+	SpanID SpanID `json:"spanId,omitempty"`
+	// trace_state conveys information about request position in multiple distributed tracing graphs.
+	// It is a trace_state in w3c-trace-context format: https://www.w3.org/TR/trace-context/#tracestate-header
+	// See also https://github.com/w3c/distributed-tracing for more details about this field.
+	TraceState string `json:"traceState,omitempty"`
+	// The `span_id` of this span's parent span. If this is a root span, then this
+	// field must be empty. The ID is an 8-byte array.
+	ParentSpanID SpanID `json:"parentSpanId,omitempty"`
+	// Flags, a bit field.
+	//
+	// Bits 0-7 (8 least significant bits) are the trace flags as defined in W3C Trace
+	// Context specification. To read the 8-bit W3C trace flag, use
+	// `flags & SPAN_FLAGS_TRACE_FLAGS_MASK`.
+	//
+	// See https://www.w3.org/TR/trace-context-2/#trace-flags for the flag definitions.
+	//
+	// Bits 8 and 9 represent the 3 states of whether a span's parent
+	// is remote. The states are (unknown, is not remote, is remote).
+	// To read whether the value is known, use `(flags & SPAN_FLAGS_CONTEXT_HAS_IS_REMOTE_MASK) != 0`.
+	// To read whether the span is remote, use `(flags & SPAN_FLAGS_CONTEXT_IS_REMOTE_MASK) != 0`.
+	//
+	// When creating span messages, if the message is logically forwarded from another source
+	// with an equivalent flags fields (i.e., usually another OTLP span message), the field SHOULD
+	// be copied as-is. If creating from a source that does not have an equivalent flags field
+	// (such as a runtime representation of an OpenTelemetry span), the high 22 bits MUST
+	// be set to zero.
+	// Readers MUST NOT assume that bits 10-31 (22 most significant bits) will be zero.
+	//
+	// [Optional].
+	Flags uint32 `json:"flags,omitempty"`
+	// A description of the span's operation.
+	//
+	// For example, the name can be a qualified method name or a file name
+	// and a line number where the operation is called. A best practice is to use
+	// the same display name at the same call point in an application.
+	// This makes it easier to correlate spans in different traces.
+	//
+	// This field is semantically required to be set to non-empty string.
+	// Empty value is equivalent to an unknown span name.
+	//
+	// This field is required.
+	Name string `json:"name"`
+	// Distinguishes between spans generated in a particular context. For example,
+	// two spans with the same name may be distinguished using `CLIENT` (caller)
+	// and `SERVER` (callee) to identify queueing latency associated with the span.
+	Kind SpanKind `json:"kind,omitempty"`
+	// start_time_unix_nano is the start time of the span. On the client side, this is the time
+	// kept by the local machine where the span execution starts. On the server side, this
+	// is the time when the server's application handler starts running.
+	// Value is UNIX Epoch time in nanoseconds since 00:00:00 UTC on 1 January 1970.
+	//
+	// This field is semantically required and it is expected that end_time >= start_time.
+	StartTime time.Time `json:"startTimeUnixNano,omitempty"`
+	// end_time_unix_nano is the end time of the span. On the client side, this is the time
+	// kept by the local machine where the span execution ends. On the server side, this
+	// is the time when the server application handler stops running.
+	// Value is UNIX Epoch time in nanoseconds since 00:00:00 UTC on 1 January 1970.
+	//
+	// This field is semantically required and it is expected that end_time >= start_time.
+	EndTime time.Time `json:"endTimeUnixNano,omitempty"`
+	// attributes is a collection of key/value pairs. Note, global attributes
+	// like server name can be set using the resource API. Examples of attributes:
+	//
+	//     "/http/user_agent": "Mozilla/5.0 (Macintosh; Intel Mac OS X 10_14_2) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/71.0.3578.98 Safari/537.36"
+	//     "/http/server_latency": 300
+	//     "example.com/myattribute": true
+	//     "example.com/score": 10.239
+	//
+	// The OpenTelemetry API specification further restricts the allowed value types:
+	// https://github.com/open-telemetry/opentelemetry-specification/blob/main/specification/common/README.md#attribute
+	// Attribute keys MUST be unique (it is not allowed to have more than one
+	// attribute with the same key).
+	Attrs []Attr `json:"attributes,omitempty"`
+	// dropped_attributes_count is the number of attributes that were discarded. Attributes
+	// can be discarded because their keys are too long or because there are too many
+	// attributes. If this value is 0, then no attributes were dropped.
+	DroppedAttrs uint32 `json:"droppedAttributesCount,omitempty"`
+	// events is a collection of Event items.
+	Events []*SpanEvent `json:"events,omitempty"`
+	// dropped_events_count is the number of dropped events. If the value is 0, then no
+	// events were dropped.
+	DroppedEvents uint32 `json:"droppedEventsCount,omitempty"`
+	// links is a collection of Links, which are references from this span to a span
+	// in the same or different trace.
+	Links []*SpanLink `json:"links,omitempty"`
+	// dropped_links_count is the number of dropped links after the maximum size was
+	// enforced. If this value is 0, then no links were dropped.
+	DroppedLinks uint32 `json:"droppedLinksCount,omitempty"`
+	// An optional final status for this span. Semantically when Status isn't set, it means
+	// span's status code is unset, i.e. assume STATUS_CODE_UNSET (code = 0).
+	Status *Status `json:"status,omitempty"`
+}
+
+// MarshalJSON encodes s into OTLP formatted JSON.
+func (s Span) MarshalJSON() ([]byte, error) {
+	startT := s.StartTime.UnixNano()
+	if s.StartTime.IsZero() || startT < 0 {
+		startT = 0
+	}
+
+	endT := s.EndTime.UnixNano()
+	if s.EndTime.IsZero() || endT < 0 {
+		endT = 0
+	}
+
+	// Override non-empty default SpanID marshal and omitempty.
+	var parentSpanId string
+	if !s.ParentSpanID.IsEmpty() {
+		b := make([]byte, hex.EncodedLen(spanIDSize))
+		hex.Encode(b, s.ParentSpanID[:])
+		parentSpanId = string(b)
+	}
+
+	type Alias Span
+	return json.Marshal(struct {
+		Alias
+		ParentSpanID string `json:"parentSpanId,omitempty"`
+		StartTime    uint64 `json:"startTimeUnixNano,omitempty"`
+		EndTime      uint64 `json:"endTimeUnixNano,omitempty"`
+	}{
+		Alias:        Alias(s),
+		ParentSpanID: parentSpanId,
+		StartTime:    uint64(startT),
+		EndTime:      uint64(endT),
+	})
+}
+
+// UnmarshalJSON decodes the OTLP formatted JSON contained in data into s.
+func (s *Span) UnmarshalJSON(data []byte) error {
+	decoder := json.NewDecoder(bytes.NewReader(data))
+
+	t, err := decoder.Token()
+	if err != nil {
+		return err
+	}
+	if t != json.Delim('{') {
+		return errors.New("invalid Span type")
+	}
+
+	for decoder.More() {
+		keyIface, err := decoder.Token()
+		if err != nil {
+			if errors.Is(err, io.EOF) {
+				// Empty.
+				return nil
+			}
+			return err
+		}
+
+		key, ok := keyIface.(string)
+		if !ok {
+			return fmt.Errorf("invalid Span field: %#v", keyIface)
+		}
+
+		switch key {
+		case "traceId", "trace_id":
+			err = decoder.Decode(&s.TraceID)
+		case "spanId", "span_id":
+			err = decoder.Decode(&s.SpanID)
+		case "traceState", "trace_state":
+			err = decoder.Decode(&s.TraceState)
+		case "parentSpanId", "parent_span_id":
+			err = decoder.Decode(&s.ParentSpanID)
+		case "flags":
+			err = decoder.Decode(&s.Flags)
+		case "name":
+			err = decoder.Decode(&s.Name)
+		case "kind":
+			err = decoder.Decode(&s.Kind)
+		case "startTimeUnixNano", "start_time_unix_nano":
+			var val protoUint64
+			err = decoder.Decode(&val)
+			s.StartTime = time.Unix(0, int64(val.Uint64()))
+		case "endTimeUnixNano", "end_time_unix_nano":
+			var val protoUint64
+			err = decoder.Decode(&val)
+			s.EndTime = time.Unix(0, int64(val.Uint64()))
+		case "attributes":
+			err = decoder.Decode(&s.Attrs)
+		case "droppedAttributesCount", "dropped_attributes_count":
+			err = decoder.Decode(&s.DroppedAttrs)
+		case "events":
+			err = decoder.Decode(&s.Events)
+		case "droppedEventsCount", "dropped_events_count":
+			err = decoder.Decode(&s.DroppedEvents)
+		case "links":
+			err = decoder.Decode(&s.Links)
+		case "droppedLinksCount", "dropped_links_count":
+			err = decoder.Decode(&s.DroppedLinks)
+		case "status":
+			err = decoder.Decode(&s.Status)
+		default:
+			// Skip unknown.
+		}
+
+		if err != nil {
+			return err
+		}
+	}
+	return nil
+}
+
+// SpanFlags represents constants used to interpret the
+// Span.flags field, which is protobuf 'fixed32' type and is to
+// be used as bit-fields. Each non-zero value defined in this enum is
+// a bit-mask.  To extract the bit-field, for example, use an
+// expression like:
+//
+//	(span.flags & SPAN_FLAGS_TRACE_FLAGS_MASK)
+//
+// See https://www.w3.org/TR/trace-context-2/#trace-flags for the flag definitions.
+//
+// Note that Span flags were introduced in version 1.1 of the
+// OpenTelemetry protocol.  Older Span producers do not set this
+// field, consequently consumers should not rely on the absence of a
+// particular flag bit to indicate the presence of a particular feature.
+type SpanFlags int32
+
+const (
+	// Bits 0-7 are used for trace flags.
+	SpanFlagsTraceFlagsMask SpanFlags = 255
+	// Bits 8 and 9 are used to indicate that the parent span or link span is remote.
+	// Bit 8 (`HAS_IS_REMOTE`) indicates whether the value is known.
+	// Bit 9 (`IS_REMOTE`) indicates whether the span or link is remote.
+	SpanFlagsContextHasIsRemoteMask SpanFlags = 256
+	// SpanFlagsContextHasIsRemoteMask indicates the Span is remote.
+	SpanFlagsContextIsRemoteMask SpanFlags = 512
+)
+
+// SpanKind is the type of span. Can be used to specify additional relationships between spans
+// in addition to a parent/child relationship.
+type SpanKind int32
+
+const (
+	// Indicates that the span represents an internal operation within an application,
+	// as opposed to an operation happening at the boundaries. Default value.
+	SpanKindInternal SpanKind = 1
+	// Indicates that the span covers server-side handling of an RPC or other
+	// remote network request.
+	SpanKindServer SpanKind = 2
+	// Indicates that the span describes a request to some remote service.
+	SpanKindClient SpanKind = 3
+	// Indicates that the span describes a producer sending a message to a broker.
+	// Unlike CLIENT and SERVER, there is often no direct critical path latency relationship
+	// between producer and consumer spans. A PRODUCER span ends when the message was accepted
+	// by the broker while the logical processing of the message might span a much longer time.
+	SpanKindProducer SpanKind = 4
+	// Indicates that the span describes consumer receiving a message from a broker.
+	// Like the PRODUCER kind, there is often no direct critical path latency relationship
+	// between producer and consumer spans.
+	SpanKindConsumer SpanKind = 5
+)
+
+// Event is a time-stamped annotation of the span, consisting of user-supplied
+// text description and key-value pairs.
+type SpanEvent struct {
+	// time_unix_nano is the time the event occurred.
+	Time time.Time `json:"timeUnixNano,omitempty"`
+	// name of the event.
+	// This field is semantically required to be set to non-empty string.
+	Name string `json:"name,omitempty"`
+	// attributes is a collection of attribute key/value pairs on the event.
+	// Attribute keys MUST be unique (it is not allowed to have more than one
+	// attribute with the same key).
+	Attrs []Attr `json:"attributes,omitempty"`
+	// dropped_attributes_count is the number of dropped attributes. If the value is 0,
+	// then no attributes were dropped.
+	DroppedAttrs uint32 `json:"droppedAttributesCount,omitempty"`
+}
+
+// MarshalJSON encodes e into OTLP formatted JSON.
+func (e SpanEvent) MarshalJSON() ([]byte, error) {
+	t := e.Time.UnixNano()
+	if e.Time.IsZero() || t < 0 {
+		t = 0
+	}
+
+	type Alias SpanEvent
+	return json.Marshal(struct {
+		Alias
+		Time uint64 `json:"timeUnixNano,omitempty"`
+	}{
+		Alias: Alias(e),
+		Time:  uint64(t),
+	})
+}
+
+// UnmarshalJSON decodes the OTLP formatted JSON contained in data into se.
+func (se *SpanEvent) UnmarshalJSON(data []byte) error {
+	decoder := json.NewDecoder(bytes.NewReader(data))
+
+	t, err := decoder.Token()
+	if err != nil {
+		return err
+	}
+	if t != json.Delim('{') {
+		return errors.New("invalid SpanEvent type")
+	}
+
+	for decoder.More() {
+		keyIface, err := decoder.Token()
+		if err != nil {
+			if errors.Is(err, io.EOF) {
+				// Empty.
+				return nil
+			}
+			return err
+		}
+
+		key, ok := keyIface.(string)
+		if !ok {
+			return fmt.Errorf("invalid SpanEvent field: %#v", keyIface)
+		}
+
+		switch key {
+		case "timeUnixNano", "time_unix_nano":
+			var val protoUint64
+			err = decoder.Decode(&val)
+			se.Time = time.Unix(0, int64(val.Uint64()))
+		case "name":
+			err = decoder.Decode(&se.Name)
+		case "attributes":
+			err = decoder.Decode(&se.Attrs)
+		case "droppedAttributesCount", "dropped_attributes_count":
+			err = decoder.Decode(&se.DroppedAttrs)
+		default:
+			// Skip unknown.
+		}
+
+		if err != nil {
+			return err
+		}
+	}
+	return nil
+}
+
+// A pointer from the current span to another span in the same trace or in a
+// different trace. For example, this can be used in batching operations,
+// where a single batch handler processes multiple requests from different
+// traces or when the handler receives a request from a different project.
+type SpanLink struct {
+	// A unique identifier of a trace that this linked span is part of. The ID is a
+	// 16-byte array.
+	TraceID TraceID `json:"traceId,omitempty"`
+	// A unique identifier for the linked span. The ID is an 8-byte array.
+	SpanID SpanID `json:"spanId,omitempty"`
+	// The trace_state associated with the link.
+	TraceState string `json:"traceState,omitempty"`
+	// attributes is a collection of attribute key/value pairs on the link.
+	// Attribute keys MUST be unique (it is not allowed to have more than one
+	// attribute with the same key).
+	Attrs []Attr `json:"attributes,omitempty"`
+	// dropped_attributes_count is the number of dropped attributes. If the value is 0,
+	// then no attributes were dropped.
+	DroppedAttrs uint32 `json:"droppedAttributesCount,omitempty"`
+	// Flags, a bit field.
+	//
+	// Bits 0-7 (8 least significant bits) are the trace flags as defined in W3C Trace
+	// Context specification. To read the 8-bit W3C trace flag, use
+	// `flags & SPAN_FLAGS_TRACE_FLAGS_MASK`.
+	//
+	// See https://www.w3.org/TR/trace-context-2/#trace-flags for the flag definitions.
+	//
+	// Bits 8 and 9 represent the 3 states of whether the link is remote.
+	// The states are (unknown, is not remote, is remote).
+	// To read whether the value is known, use `(flags & SPAN_FLAGS_CONTEXT_HAS_IS_REMOTE_MASK) != 0`.
+	// To read whether the link is remote, use `(flags & SPAN_FLAGS_CONTEXT_IS_REMOTE_MASK) != 0`.
+	//
+	// Readers MUST NOT assume that bits 10-31 (22 most significant bits) will be zero.
+	// When creating new spans, bits 10-31 (most-significant 22-bits) MUST be zero.
+	//
+	// [Optional].
+	Flags uint32 `json:"flags,omitempty"`
+}
+
+// UnmarshalJSON decodes the OTLP formatted JSON contained in data into sl.
+func (sl *SpanLink) UnmarshalJSON(data []byte) error {
+	decoder := json.NewDecoder(bytes.NewReader(data))
+
+	t, err := decoder.Token()
+	if err != nil {
+		return err
+	}
+	if t != json.Delim('{') {
+		return errors.New("invalid SpanLink type")
+	}
+
+	for decoder.More() {
+		keyIface, err := decoder.Token()
+		if err != nil {
+			if errors.Is(err, io.EOF) {
+				// Empty.
+				return nil
+			}
+			return err
+		}
+
+		key, ok := keyIface.(string)
+		if !ok {
+			return fmt.Errorf("invalid SpanLink field: %#v", keyIface)
+		}
+
+		switch key {
+		case "traceId", "trace_id":
+			err = decoder.Decode(&sl.TraceID)
+		case "spanId", "span_id":
+			err = decoder.Decode(&sl.SpanID)
+		case "traceState", "trace_state":
+			err = decoder.Decode(&sl.TraceState)
+		case "attributes":
+			err = decoder.Decode(&sl.Attrs)
+		case "droppedAttributesCount", "dropped_attributes_count":
+			err = decoder.Decode(&sl.DroppedAttrs)
+		case "flags":
+			err = decoder.Decode(&sl.Flags)
+		default:
+			// Skip unknown.
+		}
+
+		if err != nil {
+			return err
+		}
+	}
+	return nil
+}

e2e/vendor/go.opentelemetry.io/auto/sdk/internal/telemetry/status.go

@@ -0,0 +1,40 @@
+// Copyright The OpenTelemetry Authors
+// SPDX-License-Identifier: Apache-2.0
+
+package telemetry
+
+// For the semantics of status codes see
+// https://github.com/open-telemetry/opentelemetry-specification/blob/main/specification/trace/api.md#set-status
+type StatusCode int32
+
+const (
+	// The default status.
+	StatusCodeUnset StatusCode = 0
+	// The Span has been validated by an Application developer or Operator to
+	// have completed successfully.
+	StatusCodeOK StatusCode = 1
+	// The Span contains an error.
+	StatusCodeError StatusCode = 2
+)
+
+var statusCodeStrings = []string{
+	"Unset",
+	"OK",
+	"Error",
+}
+
+func (s StatusCode) String() string {
+	if s >= 0 && int(s) < len(statusCodeStrings) {
+		return statusCodeStrings[s]
+	}
+	return "<unknown telemetry.StatusCode>"
+}
+
+// The Status type defines a logical error model that is suitable for different
+// programming environments, including REST APIs and RPC APIs.
+type Status struct {
+	// A developer-facing human readable error message.
+	Message string `json:"message,omitempty"`
+	// The status code.
+	Code StatusCode `json:"code,omitempty"`
+}

e2e/vendor/go.opentelemetry.io/auto/sdk/internal/telemetry/traces.go

@@ -0,0 +1,189 @@
+// Copyright The OpenTelemetry Authors
+// SPDX-License-Identifier: Apache-2.0
+
+package telemetry
+
+import (
+	"bytes"
+	"encoding/json"
+	"errors"
+	"fmt"
+	"io"
+)
+
+// Traces represents the traces data that can be stored in a persistent storage,
+// OR can be embedded by other protocols that transfer OTLP traces data but do
+// not implement the OTLP protocol.
+//
+// The main difference between this message and collector protocol is that
+// in this message there will not be any "control" or "metadata" specific to
+// OTLP protocol.
+//
+// When new fields are added into this message, the OTLP request MUST be updated
+// as well.
+type Traces struct {
+	// An array of ResourceSpans.
+	// For data coming from a single resource this array will typically contain
+	// one element. Intermediary nodes that receive data from multiple origins
+	// typically batch the data before forwarding further and in that case this
+	// array will contain multiple elements.
+	ResourceSpans []*ResourceSpans `json:"resourceSpans,omitempty"`
+}
+
+// UnmarshalJSON decodes the OTLP formatted JSON contained in data into td.
+func (td *Traces) UnmarshalJSON(data []byte) error {
+	decoder := json.NewDecoder(bytes.NewReader(data))
+
+	t, err := decoder.Token()
+	if err != nil {
+		return err
+	}
+	if t != json.Delim('{') {
+		return errors.New("invalid TracesData type")
+	}
+
+	for decoder.More() {
+		keyIface, err := decoder.Token()
+		if err != nil {
+			if errors.Is(err, io.EOF) {
+				// Empty.
+				return nil
+			}
+			return err
+		}
+
+		key, ok := keyIface.(string)
+		if !ok {
+			return fmt.Errorf("invalid TracesData field: %#v", keyIface)
+		}
+
+		switch key {
+		case "resourceSpans", "resource_spans":
+			err = decoder.Decode(&td.ResourceSpans)
+		default:
+			// Skip unknown.
+		}
+
+		if err != nil {
+			return err
+		}
+	}
+	return nil
+}
+
+// A collection of ScopeSpans from a Resource.
+type ResourceSpans struct {
+	// The resource for the spans in this message.
+	// If this field is not set then no resource info is known.
+	Resource Resource `json:"resource"`
+	// A list of ScopeSpans that originate from a resource.
+	ScopeSpans []*ScopeSpans `json:"scopeSpans,omitempty"`
+	// This schema_url applies to the data in the "resource" field. It does not apply
+	// to the data in the "scope_spans" field which have their own schema_url field.
+	SchemaURL string `json:"schemaUrl,omitempty"`
+}
+
+// UnmarshalJSON decodes the OTLP formatted JSON contained in data into rs.
+func (rs *ResourceSpans) UnmarshalJSON(data []byte) error {
+	decoder := json.NewDecoder(bytes.NewReader(data))
+
+	t, err := decoder.Token()
+	if err != nil {
+		return err
+	}
+	if t != json.Delim('{') {
+		return errors.New("invalid ResourceSpans type")
+	}
+
+	for decoder.More() {
+		keyIface, err := decoder.Token()
+		if err != nil {
+			if errors.Is(err, io.EOF) {
+				// Empty.
+				return nil
+			}
+			return err
+		}
+
+		key, ok := keyIface.(string)
+		if !ok {
+			return fmt.Errorf("invalid ResourceSpans field: %#v", keyIface)
+		}
+
+		switch key {
+		case "resource":
+			err = decoder.Decode(&rs.Resource)
+		case "scopeSpans", "scope_spans":
+			err = decoder.Decode(&rs.ScopeSpans)
+		case "schemaUrl", "schema_url":
+			err = decoder.Decode(&rs.SchemaURL)
+		default:
+			// Skip unknown.
+		}
+
+		if err != nil {
+			return err
+		}
+	}
+	return nil
+}
+
+// A collection of Spans produced by an InstrumentationScope.
+type ScopeSpans struct {
+	// The instrumentation scope information for the spans in this message.
+	// Semantically when InstrumentationScope isn't set, it is equivalent with
+	// an empty instrumentation scope name (unknown).
+	Scope *Scope `json:"scope"`
+	// A list of Spans that originate from an instrumentation scope.
+	Spans []*Span `json:"spans,omitempty"`
+	// The Schema URL, if known. This is the identifier of the Schema that the span data
+	// is recorded in. To learn more about Schema URL see
+	// https://opentelemetry.io/docs/specs/otel/schemas/#schema-url
+	// This schema_url applies to all spans and span events in the "spans" field.
+	SchemaURL string `json:"schemaUrl,omitempty"`
+}
+
+// UnmarshalJSON decodes the OTLP formatted JSON contained in data into ss.
+func (ss *ScopeSpans) UnmarshalJSON(data []byte) error {
+	decoder := json.NewDecoder(bytes.NewReader(data))
+
+	t, err := decoder.Token()
+	if err != nil {
+		return err
+	}
+	if t != json.Delim('{') {
+		return errors.New("invalid ScopeSpans type")
+	}
+
+	for decoder.More() {
+		keyIface, err := decoder.Token()
+		if err != nil {
+			if errors.Is(err, io.EOF) {
+				// Empty.
+				return nil
+			}
+			return err
+		}
+
+		key, ok := keyIface.(string)
+		if !ok {
+			return fmt.Errorf("invalid ScopeSpans field: %#v", keyIface)
+		}
+
+		switch key {
+		case "scope":
+			err = decoder.Decode(&ss.Scope)
+		case "spans":
+			err = decoder.Decode(&ss.Spans)
+		case "schemaUrl", "schema_url":
+			err = decoder.Decode(&ss.SchemaURL)
+		default:
+			// Skip unknown.
+		}
+
+		if err != nil {
+			return err
+		}
+	}
+	return nil
+}

e2e/vendor/go.opentelemetry.io/auto/sdk/internal/telemetry/value.go

@@ -0,0 +1,452 @@
+// Copyright The OpenTelemetry Authors
+// SPDX-License-Identifier: Apache-2.0
+
+//go:generate stringer -type=ValueKind -trimprefix=ValueKind
+
+package telemetry
+
+import (
+	"bytes"
+	"cmp"
+	"encoding/base64"
+	"encoding/json"
+	"errors"
+	"fmt"
+	"io"
+	"math"
+	"slices"
+	"strconv"
+	"unsafe"
+)
+
+// A Value represents a structured value.
+// A zero value is valid and represents an empty value.
+type Value struct {
+	// Ensure forward compatibility by explicitly making this not comparable.
+	noCmp [0]func() //nolint: unused  // This is indeed used.
+
+	// num holds the value for Int64, Float64, and Bool. It holds the length
+	// for String, Bytes, Slice, Map.
+	num uint64
+	// any holds either the KindBool, KindInt64, KindFloat64, stringptr,
+	// bytesptr, sliceptr, or mapptr. If KindBool, KindInt64, or KindFloat64
+	// then the value of Value is in num as described above. Otherwise, it
+	// contains the value wrapped in the appropriate type.
+	any any
+}
+
+type (
+	// sliceptr represents a value in Value.any for KindString Values.
+	stringptr *byte
+	// bytesptr represents a value in Value.any for KindBytes Values.
+	bytesptr *byte
+	// sliceptr represents a value in Value.any for KindSlice Values.
+	sliceptr *Value
+	// mapptr represents a value in Value.any for KindMap Values.
+	mapptr *Attr
+)
+
+// ValueKind is the kind of a [Value].
+type ValueKind int
+
+// ValueKind values.
+const (
+	ValueKindEmpty ValueKind = iota
+	ValueKindBool
+	ValueKindFloat64
+	ValueKindInt64
+	ValueKindString
+	ValueKindBytes
+	ValueKindSlice
+	ValueKindMap
+)
+
+var valueKindStrings = []string{
+	"Empty",
+	"Bool",
+	"Float64",
+	"Int64",
+	"String",
+	"Bytes",
+	"Slice",
+	"Map",
+}
+
+func (k ValueKind) String() string {
+	if k >= 0 && int(k) < len(valueKindStrings) {
+		return valueKindStrings[k]
+	}
+	return "<unknown telemetry.ValueKind>"
+}
+
+// StringValue returns a new [Value] for a string.
+func StringValue(v string) Value {
+	return Value{
+		num: uint64(len(v)),
+		any: stringptr(unsafe.StringData(v)),
+	}
+}
+
+// IntValue returns a [Value] for an int.
+func IntValue(v int) Value { return Int64Value(int64(v)) }
+
+// Int64Value returns a [Value] for an int64.
+func Int64Value(v int64) Value {
+	return Value{num: uint64(v), any: ValueKindInt64}
+}
+
+// Float64Value returns a [Value] for a float64.
+func Float64Value(v float64) Value {
+	return Value{num: math.Float64bits(v), any: ValueKindFloat64}
+}
+
+// BoolValue returns a [Value] for a bool.
+func BoolValue(v bool) Value { //nolint:revive // Not a control flag.
+	var n uint64
+	if v {
+		n = 1
+	}
+	return Value{num: n, any: ValueKindBool}
+}
+
+// BytesValue returns a [Value] for a byte slice. The passed slice must not be
+// changed after it is passed.
+func BytesValue(v []byte) Value {
+	return Value{
+		num: uint64(len(v)),
+		any: bytesptr(unsafe.SliceData(v)),
+	}
+}
+
+// SliceValue returns a [Value] for a slice of [Value]. The passed slice must
+// not be changed after it is passed.
+func SliceValue(vs ...Value) Value {
+	return Value{
+		num: uint64(len(vs)),
+		any: sliceptr(unsafe.SliceData(vs)),
+	}
+}
+
+// MapValue returns a new [Value] for a slice of key-value pairs. The passed
+// slice must not be changed after it is passed.
+func MapValue(kvs ...Attr) Value {
+	return Value{
+		num: uint64(len(kvs)),
+		any: mapptr(unsafe.SliceData(kvs)),
+	}
+}
+
+// AsString returns the value held by v as a string.
+func (v Value) AsString() string {
+	if sp, ok := v.any.(stringptr); ok {
+		return unsafe.String(sp, v.num)
+	}
+	// TODO: error handle
+	return ""
+}
+
+// asString returns the value held by v as a string. It will panic if the Value
+// is not KindString.
+func (v Value) asString() string {
+	return unsafe.String(v.any.(stringptr), v.num)
+}
+
+// AsInt64 returns the value held by v as an int64.
+func (v Value) AsInt64() int64 {
+	if v.Kind() != ValueKindInt64 {
+		// TODO: error handle
+		return 0
+	}
+	return v.asInt64()
+}
+
+// asInt64 returns the value held by v as an int64. If v is not of KindInt64,
+// this will return garbage.
+func (v Value) asInt64() int64 {
+	// Assumes v.num was a valid int64 (overflow not checked).
+	return int64(v.num) // nolint: gosec
+}
+
+// AsBool returns the value held by v as a bool.
+func (v Value) AsBool() bool {
+	if v.Kind() != ValueKindBool {
+		// TODO: error handle
+		return false
+	}
+	return v.asBool()
+}
+
+// asBool returns the value held by v as a bool. If v is not of KindBool, this
+// will return garbage.
+func (v Value) asBool() bool { return v.num == 1 }
+
+// AsFloat64 returns the value held by v as a float64.
+func (v Value) AsFloat64() float64 {
+	if v.Kind() != ValueKindFloat64 {
+		// TODO: error handle
+		return 0
+	}
+	return v.asFloat64()
+}
+
+// asFloat64 returns the value held by v as a float64. If v is not of
+// KindFloat64, this will return garbage.
+func (v Value) asFloat64() float64 { return math.Float64frombits(v.num) }
+
+// AsBytes returns the value held by v as a []byte.
+func (v Value) AsBytes() []byte {
+	if sp, ok := v.any.(bytesptr); ok {
+		return unsafe.Slice((*byte)(sp), v.num)
+	}
+	// TODO: error handle
+	return nil
+}
+
+// asBytes returns the value held by v as a []byte. It will panic if the Value
+// is not KindBytes.
+func (v Value) asBytes() []byte {
+	return unsafe.Slice((*byte)(v.any.(bytesptr)), v.num)
+}
+
+// AsSlice returns the value held by v as a []Value.
+func (v Value) AsSlice() []Value {
+	if sp, ok := v.any.(sliceptr); ok {
+		return unsafe.Slice((*Value)(sp), v.num)
+	}
+	// TODO: error handle
+	return nil
+}
+
+// asSlice returns the value held by v as a []Value. It will panic if the Value
+// is not KindSlice.
+func (v Value) asSlice() []Value {
+	return unsafe.Slice((*Value)(v.any.(sliceptr)), v.num)
+}
+
+// AsMap returns the value held by v as a []Attr.
+func (v Value) AsMap() []Attr {
+	if sp, ok := v.any.(mapptr); ok {
+		return unsafe.Slice((*Attr)(sp), v.num)
+	}
+	// TODO: error handle
+	return nil
+}
+
+// asMap returns the value held by v as a []Attr. It will panic if the
+// Value is not KindMap.
+func (v Value) asMap() []Attr {
+	return unsafe.Slice((*Attr)(v.any.(mapptr)), v.num)
+}
+
+// Kind returns the Kind of v.
+func (v Value) Kind() ValueKind {
+	switch x := v.any.(type) {
+	case ValueKind:
+		return x
+	case stringptr:
+		return ValueKindString
+	case bytesptr:
+		return ValueKindBytes
+	case sliceptr:
+		return ValueKindSlice
+	case mapptr:
+		return ValueKindMap
+	default:
+		return ValueKindEmpty
+	}
+}
+
+// Empty returns if v does not hold any value.
+func (v Value) Empty() bool { return v.Kind() == ValueKindEmpty }
+
+// Equal returns if v is equal to w.
+func (v Value) Equal(w Value) bool {
+	k1 := v.Kind()
+	k2 := w.Kind()
+	if k1 != k2 {
+		return false
+	}
+	switch k1 {
+	case ValueKindInt64, ValueKindBool:
+		return v.num == w.num
+	case ValueKindString:
+		return v.asString() == w.asString()
+	case ValueKindFloat64:
+		return v.asFloat64() == w.asFloat64()
+	case ValueKindSlice:
+		return slices.EqualFunc(v.asSlice(), w.asSlice(), Value.Equal)
+	case ValueKindMap:
+		sv := sortMap(v.asMap())
+		sw := sortMap(w.asMap())
+		return slices.EqualFunc(sv, sw, Attr.Equal)
+	case ValueKindBytes:
+		return bytes.Equal(v.asBytes(), w.asBytes())
+	case ValueKindEmpty:
+		return true
+	default:
+		// TODO: error handle
+		return false
+	}
+}
+
+func sortMap(m []Attr) []Attr {
+	sm := make([]Attr, len(m))
+	copy(sm, m)
+	slices.SortFunc(sm, func(a, b Attr) int {
+		return cmp.Compare(a.Key, b.Key)
+	})
+
+	return sm
+}
+
+// String returns Value's value as a string, formatted like [fmt.Sprint].
+//
+// The returned string is meant for debugging;
+// the string representation is not stable.
+func (v Value) String() string {
+	switch v.Kind() {
+	case ValueKindString:
+		return v.asString()
+	case ValueKindInt64:
+		// Assumes v.num was a valid int64 (overflow not checked).
+		return strconv.FormatInt(int64(v.num), 10) // nolint: gosec
+	case ValueKindFloat64:
+		return strconv.FormatFloat(v.asFloat64(), 'g', -1, 64)
+	case ValueKindBool:
+		return strconv.FormatBool(v.asBool())
+	case ValueKindBytes:
+		return fmt.Sprint(v.asBytes())
+	case ValueKindMap:
+		return fmt.Sprint(v.asMap())
+	case ValueKindSlice:
+		return fmt.Sprint(v.asSlice())
+	case ValueKindEmpty:
+		return "<nil>"
+	default:
+		// Try to handle this as gracefully as possible.
+		//
+		// Don't panic here. The goal here is to have developers find this
+		// first if a slog.Kind is is not handled. It is
+		// preferable to have user's open issue asking why their attributes
+		// have a "unhandled: " prefix than say that their code is panicking.
+		return fmt.Sprintf("<unhandled telemetry.ValueKind: %s>", v.Kind())
+	}
+}
+
+// MarshalJSON encodes v into OTLP formatted JSON.
+func (v *Value) MarshalJSON() ([]byte, error) {
+	switch v.Kind() {
+	case ValueKindString:
+		return json.Marshal(struct {
+			Value string `json:"stringValue"`
+		}{v.asString()})
+	case ValueKindInt64:
+		return json.Marshal(struct {
+			Value string `json:"intValue"`
+		}{strconv.FormatInt(int64(v.num), 10)})
+	case ValueKindFloat64:
+		return json.Marshal(struct {
+			Value float64 `json:"doubleValue"`
+		}{v.asFloat64()})
+	case ValueKindBool:
+		return json.Marshal(struct {
+			Value bool `json:"boolValue"`
+		}{v.asBool()})
+	case ValueKindBytes:
+		return json.Marshal(struct {
+			Value []byte `json:"bytesValue"`
+		}{v.asBytes()})
+	case ValueKindMap:
+		return json.Marshal(struct {
+			Value struct {
+				Values []Attr `json:"values"`
+			} `json:"kvlistValue"`
+		}{struct {
+			Values []Attr `json:"values"`
+		}{v.asMap()}})
+	case ValueKindSlice:
+		return json.Marshal(struct {
+			Value struct {
+				Values []Value `json:"values"`
+			} `json:"arrayValue"`
+		}{struct {
+			Values []Value `json:"values"`
+		}{v.asSlice()}})
+	case ValueKindEmpty:
+		return nil, nil
+	default:
+		return nil, fmt.Errorf("unknown Value kind: %s", v.Kind().String())
+	}
+}
+
+// UnmarshalJSON decodes the OTLP formatted JSON contained in data into v.
+func (v *Value) UnmarshalJSON(data []byte) error {
+	decoder := json.NewDecoder(bytes.NewReader(data))
+
+	t, err := decoder.Token()
+	if err != nil {
+		return err
+	}
+	if t != json.Delim('{') {
+		return errors.New("invalid Value type")
+	}
+
+	for decoder.More() {
+		keyIface, err := decoder.Token()
+		if err != nil {
+			if errors.Is(err, io.EOF) {
+				// Empty.
+				return nil
+			}
+			return err
+		}
+
+		key, ok := keyIface.(string)
+		if !ok {
+			return fmt.Errorf("invalid Value key: %#v", keyIface)
+		}
+
+		switch key {
+		case "stringValue", "string_value":
+			var val string
+			err = decoder.Decode(&val)
+			*v = StringValue(val)
+		case "boolValue", "bool_value":
+			var val bool
+			err = decoder.Decode(&val)
+			*v = BoolValue(val)
+		case "intValue", "int_value":
+			var val protoInt64
+			err = decoder.Decode(&val)
+			*v = Int64Value(val.Int64())
+		case "doubleValue", "double_value":
+			var val float64
+			err = decoder.Decode(&val)
+			*v = Float64Value(val)
+		case "bytesValue", "bytes_value":
+			var val64 string
+			if err := decoder.Decode(&val64); err != nil {
+				return err
+			}
+			var val []byte
+			val, err = base64.StdEncoding.DecodeString(val64)
+			*v = BytesValue(val)
+		case "arrayValue", "array_value":
+			var val struct{ Values []Value }
+			err = decoder.Decode(&val)
+			*v = SliceValue(val.Values...)
+		case "kvlistValue", "kvlist_value":
+			var val struct{ Values []Attr }
+			err = decoder.Decode(&val)
+			*v = MapValue(val.Values...)
+		default:
+			// Skip unknown.
+			continue
+		}
+		// Use first valid. Ignore the rest.
+		return err
+	}
+
+	// Only unknown fields. Return nil without unmarshaling any value.
+	return nil
+}