add host.id to resource auto-detection (#3812)

* add platform specific hostIDReaders

* add WithHostID option to Resource

* add changelog entry

* Apply suggestions from code review

Co-authored-by: Tyler Yahn <MrAlias@users.noreply.github.com>

* linting

* combine platform specific readers and tests

This allows us to run tests for the BSD, Darwin, and Linux readers
on all platforms.

* add todo to use assert.AnError after resource.Detect error handling is updated

* move HostID test utilities to host_id_test

* return assert.AnError from mockHostIDProviderWithError

* use assert.ErrorIs

Co-authored-by: Tyler Yahn <MrAlias@users.noreply.github.com>

---------

Co-authored-by: Tyler Yahn <MrAlias@users.noreply.github.com>
Co-authored-by: Aaron Clawson <3766680+MadVikingGod@users.noreply.github.com>

CHANGELOG.md

@@ -10,6 +10,7 @@ This project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.htm
 
 ### Added
 
+- The `WithHostID` option to `go.opentelemetry.io/otel/sdk/resource`. (#3812)
 - The `WithoutTimestamps` option to `go.opentelemetry.io/otel/exporters/stdout/stdoutmetric` to sets all timestamps to zero. (#3828)
 - The new `Exemplar` type is added to `go.opentelemetry.io/otel/sdk/metric/metricdata`.
   Both the `DataPoint` and `HistogramDataPoint` types from that package have a new field of `Exemplars` containing the sampled exemplars for their timeseries. (#3849)

sdk/resource/config.go

@@ -71,6 +71,11 @@ func WithHost() Option {
 	return WithDetectors(host{})
 }
 
+// WithHostID adds host ID information to the configured resource.
+func WithHostID() Option {
+	return WithDetectors(hostIDDetector{})
+}
+
 // WithTelemetrySDK adds TelemetrySDK version info to the configured resource.
 func WithTelemetrySDK() Option {
 	return WithDetectors(telemetrySDK{})

sdk/resource/host_id.go

@@ -0,0 +1,142 @@
+// 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.
+
+package resource // import "go.opentelemetry.io/otel/sdk/resource"
+
+import (
+	"context"
+	"errors"
+	"os"
+	"os/exec"
+	"strings"
+
+	semconv "go.opentelemetry.io/otel/semconv/v1.17.0"
+)
+
+type hostIDProvider func() (string, error)
+
+var defaultHostIDProvider hostIDProvider = platformHostIDReader.read
+
+var hostID = defaultHostIDProvider
+
+type hostIDReader interface {
+	read() (string, error)
+}
+
+type fileReader func(string) (string, error)
+
+type commandExecutor func(string, ...string) (string, error)
+
+func readFile(filename string) (string, error) {
+	b, err := os.ReadFile(filename)
+	if err != nil {
+		return "", nil
+	}
+
+	return string(b), nil
+}
+
+// nolint: unused  // This is used by the hostReaderBSD, gated by build tags.
+func execCommand(name string, arg ...string) (string, error) {
+	cmd := exec.Command(name, arg...)
+	b, err := cmd.Output()
+	if err != nil {
+		return "", err
+	}
+
+	return string(b), nil
+}
+
+// hostIDReaderBSD implements hostIDReader.
+type hostIDReaderBSD struct {
+	execCommand commandExecutor
+	readFile    fileReader
+}
+
+// read attempts to read the machine-id from /etc/hostid. If not found it will
+// execute `kenv -q smbios.system.uuid`. If neither location yields an id an
+// error will be returned.
+func (r *hostIDReaderBSD) read() (string, error) {
+	if result, err := r.readFile("/etc/hostid"); err == nil {
+		return strings.TrimSpace(result), nil
+	}
+
+	if result, err := r.execCommand("kenv", "-q", "smbios.system.uuid"); err == nil {
+		return strings.TrimSpace(result), nil
+	}
+
+	return "", errors.New("host id not found in: /etc/hostid or kenv")
+}
+
+// hostIDReaderDarwin implements hostIDReader.
+type hostIDReaderDarwin struct {
+	execCommand commandExecutor
+}
+
+// read executes `ioreg -rd1 -c "IOPlatformExpertDevice"` and parses host id
+// from the IOPlatformUUID line. If the command fails or the uuid cannot be
+// parsed an error will be returned.
+func (r *hostIDReaderDarwin) read() (string, error) {
+	result, err := r.execCommand("ioreg", "-rd1", "-c", "IOPlatformExpertDevice")
+	if err != nil {
+		return "", err
+	}
+
+	lines := strings.Split(result, "\n")
+	for _, line := range lines {
+		if strings.Contains(line, "IOPlatformUUID") {
+			parts := strings.Split(line, " = ")
+			if len(parts) == 2 {
+				return strings.Trim(parts[1], "\""), nil
+			}
+			break
+		}
+	}
+
+	return "", errors.New("could not parse IOPlatformUUID")
+}
+
+type hostIDReaderLinux struct {
+	readFile fileReader
+}
+
+// read attempts to read the machine-id from /etc/machine-id followed by
+// /var/lib/dbus/machine-id. If neither location yields an ID an error will
+// be returned.
+func (r *hostIDReaderLinux) read() (string, error) {
+	if result, err := r.readFile("/etc/machine-id"); err == nil {
+		return strings.TrimSpace(result), nil
+	}
+
+	if result, err := r.readFile("/var/lib/dbus/machine-id"); err == nil {
+		return strings.TrimSpace(result), nil
+	}
+
+	return "", errors.New("host id not found in: /etc/machine-id or /var/lib/dbus/machine-id")
+}
+
+type hostIDDetector struct{}
+
+// Detect returns a *Resource containing the platform specific host id.
+func (hostIDDetector) Detect(ctx context.Context) (*Resource, error) {
+	hostID, err := hostID()
+	if err != nil {
+		return nil, err
+	}
+
+	return NewWithAttributes(
+		semconv.SchemaURL,
+		semconv.HostID(hostID),
+	), nil
+}

sdk/resource/host_id_bsd.go

@@ -0,0 +1,28 @@
+// 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.
+
+//go:build dragonfly || freebsd || netbsd || openbsd || solaris
+// +build dragonfly freebsd netbsd openbsd solaris
+
+package resource // import "go.opentelemetry.io/otel/sdk/resource"
+
+import (
+	"errors"
+	"strings"
+)
+
+var platformHostIDReader hostIDReader = &hostIDReaderBSD{
+	execCommand: execCommand,
+	readFile:    readFile,
+}

sdk/resource/host_id_darwin.go

@@ -0,0 +1,19 @@
+// 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.
+
+package resource // import "go.opentelemetry.io/otel/sdk/resource"
+
+var platformHostIDReader hostIDReader = &hostIDReaderDarwin{
+	execCommand: execCommand,
+}

sdk/resource/host_id_export_test.go

@@ -0,0 +1,37 @@
+// 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.
+
+package resource_test
+
+import (
+	"github.com/stretchr/testify/assert"
+
+	"go.opentelemetry.io/otel/sdk/resource"
+)
+
+func mockHostIDProvider() {
+	resource.SetHostIDProvider(
+		func() (string, error) { return "f2c668b579780554f70f72a063dc0864", nil },
+	)
+}
+
+func mockHostIDProviderWithError() {
+	resource.SetHostIDProvider(
+		func() (string, error) { return "", assert.AnError },
+	)
+}
+
+func restoreHostIDProvider() {
+	resource.SetDefaultHostIDProvider()
+}

sdk/resource/host_id_linux.go

@@ -0,0 +1,22 @@
+// 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.
+
+//go:build linux
+// +build linux
+
+package resource // import "go.opentelemetry.io/otel/sdk/resource"
+
+var platformHostIDReader hostIDReader = &hostIDReaderLinux{
+	readFile: readFile,
+}