add config parsing module

.github/dependabot.yml

@@ -109,6 +109,15 @@ updates:
     schedule:
       interval: weekly
       day: sunday
+  - package-ecosystem: gomod
+    directory: /config
+    labels:
+      - dependencies
+      - go
+      - Skip Changelog
+    schedule:
+      interval: weekly
+      day: sunday
   - package-ecosystem: gomod
     directory: /detectors/aws/ec2
     labels:

CHANGELOG.md

@@ -14,6 +14,7 @@ This project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.htm
 - Set the description for the `rpc.server.duration` metric in `go.opentelemetry.io/contrib/instrumentation/google.golang.org/grpc/otelgrpc`. (#4302)
 - Add `NewServerHandler` and `NewClientHandler` that return a `grpc.StatsHandler` used for gRPC instrumentation in `go.opentelemetry.io/contrib/instrumentation/google.golang.org/grpc/otelgrpc`. (#3002)
 - Add new Prometheus bridge module in `go.opentelemetry.io/contrib/bridges/prometheus`. (#4227)
+- Add module to parse configuration as per opentelemetry-config schema. (#4228)
 
 ### Changed
 

Makefile

@@ -74,6 +74,9 @@ $(GOTMPL): PACKAGE=go.opentelemetry.io/build-tools/gotmpl
 GORELEASE = $(TOOLS)/gorelease
 $(GORELEASE): PACKAGE=golang.org/x/exp/cmd/gorelease
 
+GOJSONSCHEMA = $(TOOLS)/go-jsonschema
+$(GOJSONSCHEMA): PACKAGE=github.com/atombender/go-jsonschema/cmd/gojsonschema
+
 tools: $(GOLANGCI_LINT) $(MISSPELL) $(GOCOVMERGE) $(STRINGER) $(PORTO) $(MULTIMOD) $(DBOTCONF) $(CROSSLINK) $(GOTMPL) $(GORELEASE)
 
 # Generate
@@ -283,3 +286,31 @@ COMMIT ?= "HEAD"
 add-tags: | $(MULTIMOD)
 	@[ "${MODSET}" ] || ( echo ">> env var MODSET is not set"; exit 1 )
 	$(MULTIMOD) verify && $(MULTIMOD) tag -m ${MODSET} -c ${COMMIT}
+
+# The source directory for opentelemetry-configuration schema.
+OPENTELEMETRY_CONFIGURATION_JSONSCHEMA_SRC_DIR=tmp/opentelememetry-configuration
+
+# The SHA matching the current version of the opentelemetry-configuration schema to use
+OPENTELEMETRY_CONFIGURATION_JSONSCHEMA_VERSION=main
+
+# Cleanup temporary directory
+genjsonschema-cleanup:
+	rm -Rf ${OPENTELEMETRY_CONFIGURATION_JSONSCHEMA_SRC_DIR}
+
+GENERATED_CONFIG=./config/generated_config.go
+
+# Generate structs for configuration from opentelemetry-configuration schema
+genjsonschema: genjsonschema-cleanup $(GOJSONSCHEMA)
+	mkdir -p ${OPENTELEMETRY_CONFIGURATION_JSONSCHEMA_SRC_DIR}
+	curl -sSL https://api.github.com/repos/open-telemetry/opentelemetry-configuration/tarball/${OPENTELEMETRY_CONFIGURATION_JSONSCHEMA_VERSION} | tar xz --strip 1 -C ${OPENTELEMETRY_CONFIGURATION_JSONSCHEMA_SRC_DIR}
+	$(GOJSONSCHEMA) \
+		--package config \
+		--tags mapstructure \
+		--output ${GENERATED_CONFIG} \
+		--schema-package=https://opentelemetry.io/otelconfig/opentelemetry_configuration.json=github.com/open-telemetry/opentelemetry-collector/schema \
+    	${OPENTELEMETRY_CONFIGURATION_JSONSCHEMA_SRC_DIR}/schema/opentelemetry_configuration.json
+	@echo Modify jsonschema generated files.
+	sed -f ./config/jsonschema_patch.sed ${GENERATED_CONFIG} > ${GENERATED_CONFIG}.tmp
+	mv ${GENERATED_CONFIG}.tmp ${GENERATED_CONFIG}
+	$(MAKE) lint
+	$(MAKE) genjsonschema-cleanup

config/config.go

@@ -0,0 +1,188 @@
+// Copyright The OpenTelemetry Authors
+// SPDX-License-Identifier: Apache-2.0
+
+package config // import "go.opentelemetry.io/contrib/config"
+
+import (
+	"fmt"
+	"net/url"
+	"strings"
+)
+
+const (
+	// Supported protocols for OTLP exporter.
+	protocolProtobufHTTP = "http/protobuf"
+	protocolProtobufGRPC = "grpc/protobuf"
+)
+
+var (
+	errInvalidExporterConfiguration = fmt.Errorf("invalid exporter configuration")
+	errUnsupportedSpanProcessorType = fmt.Errorf("unsupported span processor type")
+	errUnsupportedMetricReaderType  = fmt.Errorf("unsupported metric reader type")
+)
+
+// Validate checks for a valid batch processor for the SpanProcessor.
+func (sp *SpanProcessor) Validate() error {
+	if sp.Batch != nil {
+		return sp.Batch.Exporter.Validate()
+	}
+	return errUnsupportedSpanProcessorType
+}
+
+// Validate checks for valid exporters to be configured for the SpanExporter.
+func (se *SpanExporter) Validate() error {
+	if se.Console == nil && se.Otlp == nil {
+		return errInvalidExporterConfiguration
+	}
+	return nil
+}
+
+// Validate checks the configuration for Prometheus exporter.
+func (p *Prometheus) Validate() error {
+	if p.Host == nil {
+		return fmt.Errorf("host must be specified")
+	}
+	if p.Port == nil {
+		return fmt.Errorf("port must be specified")
+	}
+	return nil
+}
+
+// Validate checks the configuration for OtlpMetric exporter.
+func (om *OtlpMetric) Validate() error {
+	switch om.Protocol {
+	case protocolProtobufHTTP:
+	case protocolProtobufGRPC:
+	default:
+		return fmt.Errorf("unsupported protocol %s", om.Protocol)
+	}
+
+	if len(om.Endpoint) > 0 {
+		_, err := url.ParseRequestURI(normalizeEndpoint(om.Endpoint))
+		if err != nil {
+			return err
+		}
+	}
+	if om.Compression != nil {
+		switch *om.Compression {
+		case "gzip":
+		case "none":
+		default:
+			return fmt.Errorf("unsupported compression %q", *om.Compression)
+		}
+	}
+	return nil
+}
+
+// Validate checks for either a valid pull or periodic exporter for the MetricReader.
+func (mr *MetricReader) Validate() error {
+	if mr.Pull != nil {
+		return mr.Pull.Validate()
+	}
+	if mr.Periodic != nil {
+		return mr.Periodic.Validate()
+	}
+
+	return errUnsupportedMetricReaderType
+}
+
+// Validate checks for valid exporters to be configured for the PullMetricReader.
+func (pmr *PullMetricReader) Validate() error {
+	if pmr.Exporter.Prometheus == nil {
+		return errInvalidExporterConfiguration
+	}
+	return pmr.Exporter.Validate()
+}
+
+// Validate calls the configured exporter's Validate method.
+func (me *MetricExporter) Validate() error {
+	if me.Otlp != nil {
+		return me.Otlp.Validate()
+	}
+	if me.Console != nil {
+		return nil
+	}
+	if me.Prometheus != nil {
+		return me.Prometheus.Validate()
+	}
+	return errInvalidExporterConfiguration
+}
+
+// Validate checks for valid exporters to be configured for the PeriodicMetricReader.
+func (pmr *PeriodicMetricReader) Validate() error {
+	if pmr.Exporter.Otlp == nil && pmr.Exporter.Console == nil {
+		return errInvalidExporterConfiguration
+	}
+	return pmr.Exporter.Validate()
+}
+
+// Validate checks for a valid Selector or Stream to be configured for the View.
+func (v *View) Validate() error {
+	if v.Selector == nil || v.Stream == nil {
+		return fmt.Errorf("invalid view configuration")
+	}
+	return nil
+}
+
+func (s *ViewSelector) instrumentNameStr() string {
+	if s.InstrumentName == nil {
+		return ""
+	}
+	return *s.InstrumentName
+}
+
+func (s *ViewSelector) meterNameStr() string {
+	if s.MeterName == nil {
+		return ""
+	}
+	return *s.MeterName
+}
+
+func (s *ViewSelector) meterVersionStr() string {
+	if s.MeterVersion == nil {
+		return ""
+	}
+	return *s.MeterVersion
+}
+
+func (s *ViewSelector) meterSchemaURLStr() string {
+	if s.MeterSchemaUrl == nil {
+		return ""
+	}
+	return *s.MeterSchemaUrl
+}
+
+func (s *ViewSelector) unitStr() string {
+	if s.Unit == nil {
+		return ""
+	}
+	return *s.Unit
+}
+
+func (s *ViewStream) nameStr() string {
+	if s.Name == nil {
+		return ""
+	}
+	return *s.Name
+}
+
+func (s *ViewStream) descriptionStr() string {
+	if s.Description == nil {
+		return ""
+	}
+	return *s.Description
+}
+
+func (e *ViewStreamAggregationExplicitBucketHistogram) recordMinMaxBool() bool {
+	if e.RecordMinMax == nil {
+		return false
+	}
+	return *e.RecordMinMax
+}
+
+func normalizeEndpoint(endpoint string) string {
+	if !strings.HasPrefix(endpoint, "https://") && !strings.HasPrefix(endpoint, "http://") {
+		return fmt.Sprintf("http://%s", endpoint)
+	}
+	return endpoint
+}