Phase 2: Implement Execution Environment Abstraction (v0.3.0)

This commit implements Phase 2 of the CHORUS Task Execution Engine development plan,
providing a comprehensive execution environment abstraction layer with Docker
container sandboxing support.

## New Features

### Core Sandbox Interface
- Comprehensive ExecutionSandbox interface with isolated task execution
- Support for command execution, file I/O, environment management
- Resource usage monitoring and sandbox lifecycle management
- Standardized error handling with SandboxError types and categories

### Docker Container Sandbox Implementation
- Full Docker API integration with secure container creation
- Transparent repository mounting with configurable read/write access
- Advanced security policies with capability dropping and privilege controls
- Comprehensive resource limits (CPU, memory, disk, processes, file handles)
- Support for tmpfs mounts, masked paths, and read-only bind mounts
- Container lifecycle management with proper cleanup and health monitoring

### Security & Resource Management
- Configurable security policies with SELinux, AppArmor, and Seccomp support
- Fine-grained capability management with secure defaults
- Network isolation options with configurable DNS and proxy settings
- Resource monitoring with real-time CPU, memory, and network usage tracking
- Comprehensive ulimits configuration for process and file handle limits

### Repository Integration
- Seamless repository mounting from local paths to container workspaces
- Git configuration support with user credentials and global settings
- File inclusion/exclusion patterns for selective repository access
- Configurable permissions and ownership for mounted repositories

### Testing Infrastructure
- Comprehensive test suite with 60+ test cases covering all functionality
- Docker integration tests with Alpine Linux containers (skipped in short mode)
- Mock sandbox implementation for unit testing without Docker dependencies
- Security policy validation tests with read-only filesystem enforcement
- Resource usage monitoring and cleanup verification tests

## Technical Details

### Dependencies Added
- github.com/docker/docker v28.4.0+incompatible - Docker API client
- github.com/docker/go-connections v0.6.0 - Docker connection utilities
- github.com/docker/go-units v0.5.0 - Docker units and formatting
- Associated Docker API dependencies for complete container management

### Architecture
- Interface-driven design enabling multiple sandbox implementations
- Comprehensive configuration structures for all sandbox aspects
- Resource usage tracking with detailed metrics collection
- Error handling with retryable error classification
- Proper cleanup and resource management throughout sandbox lifecycle

### Compatibility
- Maintains backward compatibility with existing CHORUS architecture
- Designed for future integration with Phase 3 Core Task Execution Engine
- Extensible design supporting additional sandbox implementations (VM, process)

This Phase 2 implementation provides the foundation for secure, isolated task
execution that will be integrated with the AI model providers from Phase 1
in the upcoming Phase 3 development.

🤖 Generated with [Claude Code](https://claude.ai/code)

Co-Authored-By: Claude <noreply@anthropic.com>

vendor/go.opentelemetry.io/otel/internal/global/meter.go

@@ -1,23 +1,13 @@
 // Copyright The OpenTelemetry Authors
-//
-// 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.
+// SPDX-License-Identifier: Apache-2.0
 
 package global // import "go.opentelemetry.io/otel/internal/global"
 
 import (
 	"container/list"
+	"context"
+	"reflect"
 	"sync"
-	"sync/atomic"
 
 	"go.opentelemetry.io/otel/metric"
 	"go.opentelemetry.io/otel/metric/embedded"
@@ -76,6 +66,8 @@ func (p *meterProvider) Meter(name string, opts ...metric.MeterOption) metric.Me
 	key := il{
 		name:    name,
 		version: c.InstrumentationVersion(),
+		schema:  c.SchemaURL(),
+		attrs:   c.InstrumentationAttributes(),
 	}
 
 	if p.meters == nil {
@@ -86,7 +78,7 @@ func (p *meterProvider) Meter(name string, opts ...metric.MeterOption) metric.Me
 		return val
 	}
 
-	t := &meter{name: name, opts: opts}
+	t := &meter{name: name, opts: opts, instruments: make(map[instID]delegatedInstrument)}
 	p.meters[key] = t
 	return t
 }
@@ -102,17 +94,29 @@ type meter struct {
 	opts []metric.MeterOption
 
 	mtx         sync.Mutex
-	instruments []delegatedInstrument
+	instruments map[instID]delegatedInstrument
 
 	registry list.List
 
-	delegate atomic.Value // metric.Meter
+	delegate metric.Meter
 }
 
 type delegatedInstrument interface {
 	setDelegate(metric.Meter)
 }
 
+// instID are the identifying properties of a instrument.
+type instID struct {
+	// name is the name of the stream.
+	name string
+	// description is the description of the stream.
+	description string
+	// kind defines the functional group of the instrument.
+	kind reflect.Type
+	// unit is the unit of the stream.
+	unit string
+}
+
 // setDelegate configures m to delegate all Meter functionality to Meters
 // created by provider.
 //
@@ -120,19 +124,21 @@ type delegatedInstrument interface {
 //
 // It is guaranteed by the caller that this happens only once.
 func (m *meter) setDelegate(provider metric.MeterProvider) {
-	meter := provider.Meter(m.name, m.opts...)
-	m.delegate.Store(meter)
-
 	m.mtx.Lock()
 	defer m.mtx.Unlock()
 
+	meter := provider.Meter(m.name, m.opts...)
+	m.delegate = meter
+
 	for _, inst := range m.instruments {
 		inst.setDelegate(meter)
 	}
 
-	for e := m.registry.Front(); e != nil; e = e.Next() {
+	var n *list.Element
+	for e := m.registry.Front(); e != nil; e = n {
 		r := e.Value.(*registration)
 		r.setDelegate(meter)
+		n = e.Next()
 		m.registry.Remove(e)
 	}
 
@@ -141,147 +147,363 @@ func (m *meter) setDelegate(provider metric.MeterProvider) {
 }
 
 func (m *meter) Int64Counter(name string, options ...metric.Int64CounterOption) (metric.Int64Counter, error) {
-	if del, ok := m.delegate.Load().(metric.Meter); ok {
-		return del.Int64Counter(name, options...)
-	}
 	m.mtx.Lock()
 	defer m.mtx.Unlock()
+
+	if m.delegate != nil {
+		return m.delegate.Int64Counter(name, options...)
+	}
+
+	cfg := metric.NewInt64CounterConfig(options...)
+	id := instID{
+		name:        name,
+		kind:        reflect.TypeOf((*siCounter)(nil)),
+		description: cfg.Description(),
+		unit:        cfg.Unit(),
+	}
+	if f, ok := m.instruments[id]; ok {
+		return f.(metric.Int64Counter), nil
+	}
 	i := &siCounter{name: name, opts: options}
-	m.instruments = append(m.instruments, i)
+	m.instruments[id] = i
 	return i, nil
 }
 
-func (m *meter) Int64UpDownCounter(name string, options ...metric.Int64UpDownCounterOption) (metric.Int64UpDownCounter, error) {
-	if del, ok := m.delegate.Load().(metric.Meter); ok {
-		return del.Int64UpDownCounter(name, options...)
-	}
+func (m *meter) Int64UpDownCounter(
+	name string,
+	options ...metric.Int64UpDownCounterOption,
+) (metric.Int64UpDownCounter, error) {
 	m.mtx.Lock()
 	defer m.mtx.Unlock()
+
+	if m.delegate != nil {
+		return m.delegate.Int64UpDownCounter(name, options...)
+	}
+
+	cfg := metric.NewInt64UpDownCounterConfig(options...)
+	id := instID{
+		name:        name,
+		kind:        reflect.TypeOf((*siUpDownCounter)(nil)),
+		description: cfg.Description(),
+		unit:        cfg.Unit(),
+	}
+	if f, ok := m.instruments[id]; ok {
+		return f.(metric.Int64UpDownCounter), nil
+	}
 	i := &siUpDownCounter{name: name, opts: options}
-	m.instruments = append(m.instruments, i)
+	m.instruments[id] = i
 	return i, nil
 }
 
 func (m *meter) Int64Histogram(name string, options ...metric.Int64HistogramOption) (metric.Int64Histogram, error) {
-	if del, ok := m.delegate.Load().(metric.Meter); ok {
-		return del.Int64Histogram(name, options...)
-	}
 	m.mtx.Lock()
 	defer m.mtx.Unlock()
+
+	if m.delegate != nil {
+		return m.delegate.Int64Histogram(name, options...)
+	}
+
+	cfg := metric.NewInt64HistogramConfig(options...)
+	id := instID{
+		name:        name,
+		kind:        reflect.TypeOf((*siHistogram)(nil)),
+		description: cfg.Description(),
+		unit:        cfg.Unit(),
+	}
+	if f, ok := m.instruments[id]; ok {
+		return f.(metric.Int64Histogram), nil
+	}
 	i := &siHistogram{name: name, opts: options}
-	m.instruments = append(m.instruments, i)
+	m.instruments[id] = i
 	return i, nil
 }
 
-func (m *meter) Int64ObservableCounter(name string, options ...metric.Int64ObservableCounterOption) (metric.Int64ObservableCounter, error) {
-	if del, ok := m.delegate.Load().(metric.Meter); ok {
-		return del.Int64ObservableCounter(name, options...)
-	}
+func (m *meter) Int64Gauge(name string, options ...metric.Int64GaugeOption) (metric.Int64Gauge, error) {
 	m.mtx.Lock()
 	defer m.mtx.Unlock()
+
+	if m.delegate != nil {
+		return m.delegate.Int64Gauge(name, options...)
+	}
+
+	cfg := metric.NewInt64GaugeConfig(options...)
+	id := instID{
+		name:        name,
+		kind:        reflect.TypeOf((*siGauge)(nil)),
+		description: cfg.Description(),
+		unit:        cfg.Unit(),
+	}
+	if f, ok := m.instruments[id]; ok {
+		return f.(metric.Int64Gauge), nil
+	}
+	i := &siGauge{name: name, opts: options}
+	m.instruments[id] = i
+	return i, nil
+}
+
+func (m *meter) Int64ObservableCounter(
+	name string,
+	options ...metric.Int64ObservableCounterOption,
+) (metric.Int64ObservableCounter, error) {
+	m.mtx.Lock()
+	defer m.mtx.Unlock()
+
+	if m.delegate != nil {
+		return m.delegate.Int64ObservableCounter(name, options...)
+	}
+
+	cfg := metric.NewInt64ObservableCounterConfig(options...)
+	id := instID{
+		name:        name,
+		kind:        reflect.TypeOf((*aiCounter)(nil)),
+		description: cfg.Description(),
+		unit:        cfg.Unit(),
+	}
+	if f, ok := m.instruments[id]; ok {
+		return f.(metric.Int64ObservableCounter), nil
+	}
 	i := &aiCounter{name: name, opts: options}
-	m.instruments = append(m.instruments, i)
+	m.instruments[id] = i
 	return i, nil
 }
 
-func (m *meter) Int64ObservableUpDownCounter(name string, options ...metric.Int64ObservableUpDownCounterOption) (metric.Int64ObservableUpDownCounter, error) {
-	if del, ok := m.delegate.Load().(metric.Meter); ok {
-		return del.Int64ObservableUpDownCounter(name, options...)
-	}
+func (m *meter) Int64ObservableUpDownCounter(
+	name string,
+	options ...metric.Int64ObservableUpDownCounterOption,
+) (metric.Int64ObservableUpDownCounter, error) {
 	m.mtx.Lock()
 	defer m.mtx.Unlock()
+
+	if m.delegate != nil {
+		return m.delegate.Int64ObservableUpDownCounter(name, options...)
+	}
+
+	cfg := metric.NewInt64ObservableUpDownCounterConfig(options...)
+	id := instID{
+		name:        name,
+		kind:        reflect.TypeOf((*aiUpDownCounter)(nil)),
+		description: cfg.Description(),
+		unit:        cfg.Unit(),
+	}
+	if f, ok := m.instruments[id]; ok {
+		return f.(metric.Int64ObservableUpDownCounter), nil
+	}
 	i := &aiUpDownCounter{name: name, opts: options}
-	m.instruments = append(m.instruments, i)
+	m.instruments[id] = i
 	return i, nil
 }
 
-func (m *meter) Int64ObservableGauge(name string, options ...metric.Int64ObservableGaugeOption) (metric.Int64ObservableGauge, error) {
-	if del, ok := m.delegate.Load().(metric.Meter); ok {
-		return del.Int64ObservableGauge(name, options...)
-	}
+func (m *meter) Int64ObservableGauge(
+	name string,
+	options ...metric.Int64ObservableGaugeOption,
+) (metric.Int64ObservableGauge, error) {
 	m.mtx.Lock()
 	defer m.mtx.Unlock()
+
+	if m.delegate != nil {
+		return m.delegate.Int64ObservableGauge(name, options...)
+	}
+
+	cfg := metric.NewInt64ObservableGaugeConfig(options...)
+	id := instID{
+		name:        name,
+		kind:        reflect.TypeOf((*aiGauge)(nil)),
+		description: cfg.Description(),
+		unit:        cfg.Unit(),
+	}
+	if f, ok := m.instruments[id]; ok {
+		return f.(metric.Int64ObservableGauge), nil
+	}
 	i := &aiGauge{name: name, opts: options}
-	m.instruments = append(m.instruments, i)
+	m.instruments[id] = i
 	return i, nil
 }
 
 func (m *meter) Float64Counter(name string, options ...metric.Float64CounterOption) (metric.Float64Counter, error) {
-	if del, ok := m.delegate.Load().(metric.Meter); ok {
-		return del.Float64Counter(name, options...)
-	}
 	m.mtx.Lock()
 	defer m.mtx.Unlock()
+
+	if m.delegate != nil {
+		return m.delegate.Float64Counter(name, options...)
+	}
+
+	cfg := metric.NewFloat64CounterConfig(options...)
+	id := instID{
+		name:        name,
+		kind:        reflect.TypeOf((*sfCounter)(nil)),
+		description: cfg.Description(),
+		unit:        cfg.Unit(),
+	}
+	if f, ok := m.instruments[id]; ok {
+		return f.(metric.Float64Counter), nil
+	}
 	i := &sfCounter{name: name, opts: options}
-	m.instruments = append(m.instruments, i)
+	m.instruments[id] = i
 	return i, nil
 }
 
-func (m *meter) Float64UpDownCounter(name string, options ...metric.Float64UpDownCounterOption) (metric.Float64UpDownCounter, error) {
-	if del, ok := m.delegate.Load().(metric.Meter); ok {
-		return del.Float64UpDownCounter(name, options...)
-	}
+func (m *meter) Float64UpDownCounter(
+	name string,
+	options ...metric.Float64UpDownCounterOption,
+) (metric.Float64UpDownCounter, error) {
 	m.mtx.Lock()
 	defer m.mtx.Unlock()
+
+	if m.delegate != nil {
+		return m.delegate.Float64UpDownCounter(name, options...)
+	}
+
+	cfg := metric.NewFloat64UpDownCounterConfig(options...)
+	id := instID{
+		name:        name,
+		kind:        reflect.TypeOf((*sfUpDownCounter)(nil)),
+		description: cfg.Description(),
+		unit:        cfg.Unit(),
+	}
+	if f, ok := m.instruments[id]; ok {
+		return f.(metric.Float64UpDownCounter), nil
+	}
 	i := &sfUpDownCounter{name: name, opts: options}
-	m.instruments = append(m.instruments, i)
+	m.instruments[id] = i
 	return i, nil
 }
 
-func (m *meter) Float64Histogram(name string, options ...metric.Float64HistogramOption) (metric.Float64Histogram, error) {
-	if del, ok := m.delegate.Load().(metric.Meter); ok {
-		return del.Float64Histogram(name, options...)
-	}
+func (m *meter) Float64Histogram(
+	name string,
+	options ...metric.Float64HistogramOption,
+) (metric.Float64Histogram, error) {
 	m.mtx.Lock()
 	defer m.mtx.Unlock()
+
+	if m.delegate != nil {
+		return m.delegate.Float64Histogram(name, options...)
+	}
+
+	cfg := metric.NewFloat64HistogramConfig(options...)
+	id := instID{
+		name:        name,
+		kind:        reflect.TypeOf((*sfHistogram)(nil)),
+		description: cfg.Description(),
+		unit:        cfg.Unit(),
+	}
+	if f, ok := m.instruments[id]; ok {
+		return f.(metric.Float64Histogram), nil
+	}
 	i := &sfHistogram{name: name, opts: options}
-	m.instruments = append(m.instruments, i)
+	m.instruments[id] = i
 	return i, nil
 }
 
-func (m *meter) Float64ObservableCounter(name string, options ...metric.Float64ObservableCounterOption) (metric.Float64ObservableCounter, error) {
-	if del, ok := m.delegate.Load().(metric.Meter); ok {
-		return del.Float64ObservableCounter(name, options...)
-	}
+func (m *meter) Float64Gauge(name string, options ...metric.Float64GaugeOption) (metric.Float64Gauge, error) {
 	m.mtx.Lock()
 	defer m.mtx.Unlock()
+
+	if m.delegate != nil {
+		return m.delegate.Float64Gauge(name, options...)
+	}
+
+	cfg := metric.NewFloat64GaugeConfig(options...)
+	id := instID{
+		name:        name,
+		kind:        reflect.TypeOf((*sfGauge)(nil)),
+		description: cfg.Description(),
+		unit:        cfg.Unit(),
+	}
+	if f, ok := m.instruments[id]; ok {
+		return f.(metric.Float64Gauge), nil
+	}
+	i := &sfGauge{name: name, opts: options}
+	m.instruments[id] = i
+	return i, nil
+}
+
+func (m *meter) Float64ObservableCounter(
+	name string,
+	options ...metric.Float64ObservableCounterOption,
+) (metric.Float64ObservableCounter, error) {
+	m.mtx.Lock()
+	defer m.mtx.Unlock()
+
+	if m.delegate != nil {
+		return m.delegate.Float64ObservableCounter(name, options...)
+	}
+
+	cfg := metric.NewFloat64ObservableCounterConfig(options...)
+	id := instID{
+		name:        name,
+		kind:        reflect.TypeOf((*afCounter)(nil)),
+		description: cfg.Description(),
+		unit:        cfg.Unit(),
+	}
+	if f, ok := m.instruments[id]; ok {
+		return f.(metric.Float64ObservableCounter), nil
+	}
 	i := &afCounter{name: name, opts: options}
-	m.instruments = append(m.instruments, i)
+	m.instruments[id] = i
 	return i, nil
 }
 
-func (m *meter) Float64ObservableUpDownCounter(name string, options ...metric.Float64ObservableUpDownCounterOption) (metric.Float64ObservableUpDownCounter, error) {
-	if del, ok := m.delegate.Load().(metric.Meter); ok {
-		return del.Float64ObservableUpDownCounter(name, options...)
-	}
+func (m *meter) Float64ObservableUpDownCounter(
+	name string,
+	options ...metric.Float64ObservableUpDownCounterOption,
+) (metric.Float64ObservableUpDownCounter, error) {
 	m.mtx.Lock()
 	defer m.mtx.Unlock()
+
+	if m.delegate != nil {
+		return m.delegate.Float64ObservableUpDownCounter(name, options...)
+	}
+
+	cfg := metric.NewFloat64ObservableUpDownCounterConfig(options...)
+	id := instID{
+		name:        name,
+		kind:        reflect.TypeOf((*afUpDownCounter)(nil)),
+		description: cfg.Description(),
+		unit:        cfg.Unit(),
+	}
+	if f, ok := m.instruments[id]; ok {
+		return f.(metric.Float64ObservableUpDownCounter), nil
+	}
 	i := &afUpDownCounter{name: name, opts: options}
-	m.instruments = append(m.instruments, i)
+	m.instruments[id] = i
 	return i, nil
 }
 
-func (m *meter) Float64ObservableGauge(name string, options ...metric.Float64ObservableGaugeOption) (metric.Float64ObservableGauge, error) {
-	if del, ok := m.delegate.Load().(metric.Meter); ok {
-		return del.Float64ObservableGauge(name, options...)
-	}
+func (m *meter) Float64ObservableGauge(
+	name string,
+	options ...metric.Float64ObservableGaugeOption,
+) (metric.Float64ObservableGauge, error) {
 	m.mtx.Lock()
 	defer m.mtx.Unlock()
+
+	if m.delegate != nil {
+		return m.delegate.Float64ObservableGauge(name, options...)
+	}
+
+	cfg := metric.NewFloat64ObservableGaugeConfig(options...)
+	id := instID{
+		name:        name,
+		kind:        reflect.TypeOf((*afGauge)(nil)),
+		description: cfg.Description(),
+		unit:        cfg.Unit(),
+	}
+	if f, ok := m.instruments[id]; ok {
+		return f.(metric.Float64ObservableGauge), nil
+	}
 	i := &afGauge{name: name, opts: options}
-	m.instruments = append(m.instruments, i)
+	m.instruments[id] = i
 	return i, nil
 }
 
 // RegisterCallback captures the function that will be called during Collect.
 func (m *meter) RegisterCallback(f metric.Callback, insts ...metric.Observable) (metric.Registration, error) {
-	if del, ok := m.delegate.Load().(metric.Meter); ok {
-		insts = unwrapInstruments(insts)
-		return del.RegisterCallback(f, insts...)
-	}
-
 	m.mtx.Lock()
 	defer m.mtx.Unlock()
 
+	if m.delegate != nil {
+		return m.delegate.RegisterCallback(unwrapCallback(f), unwrapInstruments(insts)...)
+	}
+
 	reg := &registration{instruments: insts, function: f}
 	e := m.registry.PushBack(reg)
 	reg.unreg = func() error {
@@ -293,15 +515,11 @@ func (m *meter) RegisterCallback(f metric.Callback, insts ...metric.Observable)
 	return reg, nil
 }
 
-type wrapped interface {
-	unwrap() metric.Observable
-}
-
 func unwrapInstruments(instruments []metric.Observable) []metric.Observable {
 	out := make([]metric.Observable, 0, len(instruments))
 
 	for _, inst := range instruments {
-		if in, ok := inst.(wrapped); ok {
+		if in, ok := inst.(unwrapper); ok {
 			out = append(out, in.unwrap())
 		} else {
 			out = append(out, inst)
@@ -321,9 +539,61 @@ type registration struct {
 	unregMu sync.Mutex
 }
 
-func (c *registration) setDelegate(m metric.Meter) {
-	insts := unwrapInstruments(c.instruments)
+type unwrapObs struct {
+	embedded.Observer
+	obs metric.Observer
+}
 
+// unwrapFloat64Observable returns an expected metric.Float64Observable after
+// unwrapping the global object.
+func unwrapFloat64Observable(inst metric.Float64Observable) metric.Float64Observable {
+	if unwrapped, ok := inst.(unwrapper); ok {
+		if floatObs, ok := unwrapped.unwrap().(metric.Float64Observable); ok {
+			// Note: if the unwrapped object does not
+			// unwrap as an observable for either of the
+			// predicates here, it means an internal bug in
+			// this package.  We avoid logging an error in
+			// this case, because the SDK has to try its
+			// own type conversion on the object.  The SDK
+			// will see this and be forced to respond with
+			// its own error.
+			//
+			// This code uses a double-nested if statement
+			// to avoid creating a branch that is
+			// impossible to cover.
+			inst = floatObs
+		}
+	}
+	return inst
+}
+
+// unwrapInt64Observable returns an expected metric.Int64Observable after
+// unwrapping the global object.
+func unwrapInt64Observable(inst metric.Int64Observable) metric.Int64Observable {
+	if unwrapped, ok := inst.(unwrapper); ok {
+		if unint, ok := unwrapped.unwrap().(metric.Int64Observable); ok {
+			// See the comment in unwrapFloat64Observable().
+			inst = unint
+		}
+	}
+	return inst
+}
+
+func (uo *unwrapObs) ObserveFloat64(inst metric.Float64Observable, value float64, opts ...metric.ObserveOption) {
+	uo.obs.ObserveFloat64(unwrapFloat64Observable(inst), value, opts...)
+}
+
+func (uo *unwrapObs) ObserveInt64(inst metric.Int64Observable, value int64, opts ...metric.ObserveOption) {
+	uo.obs.ObserveInt64(unwrapInt64Observable(inst), value, opts...)
+}
+
+func unwrapCallback(f metric.Callback) metric.Callback {
+	return func(ctx context.Context, obs metric.Observer) error {
+		return f(ctx, &unwrapObs{obs: obs})
+	}
+}
+
+func (c *registration) setDelegate(m metric.Meter) {
 	c.unregMu.Lock()
 	defer c.unregMu.Unlock()
 
@@ -332,9 +602,10 @@ func (c *registration) setDelegate(m metric.Meter) {
 		return
 	}
 
-	reg, err := m.RegisterCallback(c.function, insts...)
+	reg, err := m.RegisterCallback(unwrapCallback(c.function), unwrapInstruments(c.instruments)...)
 	if err != nil {
 		GetErrorHandler().Handle(err)
+		return
 	}
 
 	c.unreg = reg.Unregister