Line data    Source code

       1              : // Licensed under the Apache License, Version 2.0
       2              : // Copyright 2025, Michael Bushe, All rights reserved.
       3              : 
       4              : library;
       5              : 
       6              : import 'package:dartastic_opentelemetry/src/otel.dart';
       7              : import 'package:dartastic_opentelemetry_api/dartastic_opentelemetry_api.dart';
       8              : import 'package:meta/meta.dart';
       9              : 
      10              : part 'resource_create.dart';
      11              : 
      12              : /// Represents a resource, which captures identifying information about the entities
      13              : /// for which signals (stats, traces, and logs) are reported.
      14              : ///
      15              : /// A Resource is an immutable collection of attributes that provide information
      16              : /// about the entity producing telemetry. Resources are a core concept of OpenTelemetry's
      17              : /// identity model.
      18              : ///
      19              : /// More information:
      20              : /// https://opentelemetry.io/docs/specs/otel/resource/sdk/
      21              : ///
      22              : /// Note: Per [OTEP 0265](https://github.com/open-telemetry/opentelemetry-specification/blob/main/oteps/0265-event-vision.md),
      23              : /// span events are being deprecated and will be replaced by the Logging API.
      24              : @immutable
      25              : class Resource {
      26              :   final Attributes _attributes;
      27              :   final String? _schemaUrl;
      28              : 
      29              :   /// An empty resource with no attributes.
      30              :   ///
      31              :   /// This is a convenience constant for when no resource attributes are needed.
      32          225 :   static final Resource empty = Resource._(OTel.attributesFromMap({}));
      33              : 
      34              :   /// Gets the attributes describing this resource.
      35          146 :   Attributes get attributes => _attributes;
      36              : 
      37              :   /// Gets the schema URL for this resource's attributes, if any.
      38            2 :   String? get schemaUrl => _schemaUrl;
      39              : 
      40              :   /// Private constructor for creating Resource instances.
      41              :   ///
      42              :   /// Resources should be created through the [OTel.resource] method
      43              :   /// or [ResourceCreate.create] method, not directly.
      44           73 :   Resource._(Attributes attributes, [String? schemaUrl])
      45              :       : _attributes = attributes,
      46              :         _schemaUrl = schemaUrl;
      47              : 
      48              :   /// Merges this resource with another resource.
      49              :   ///
      50              :   /// The resulting resource contains the combined attributes of both resources.
      51              :   /// If there are attributes with the same key, the attributes from the other
      52              :   /// resource will take precedence.
      53              :   ///
      54              :   /// For schema URLs, the following rules apply:
      55              :   /// - If one schema URL is empty, use the non-empty one
      56              :   /// - If both schema URLs are the same, use that schema URL
      57              :   /// - If both schema URLs are different and non-empty, use the other resource's schema URL
      58              :   ///
      59              :   /// @param other The resource to merge with this resource
      60              :   /// @return A new resource with the merged attributes
      61           45 :   Resource merge(Resource other) {
      62           45 :     final mergedMap = <String, Object>{};
      63              : 
      64              :     // Add current attributes
      65          180 :     _attributes.toMap().forEach((key, value) {
      66           90 :       mergedMap[key] = value.value;
      67              :     });
      68              : 
      69              :     // Add other resource's attributes (they take precedence)
      70          180 :     other._attributes.toMap().forEach((key, value) {
      71           90 :       mergedMap[key] = value.value;
      72              :     });
      73              : 
      74              :     // Handle schema URL merging according to spec
      75              :     String? mergedSchemaUrl;
      76           45 :     if (_schemaUrl == null || _schemaUrl!.isEmpty) {
      77           45 :       mergedSchemaUrl = other._schemaUrl;
      78            0 :     } else if (other._schemaUrl == null || other._schemaUrl!.isEmpty) {
      79            0 :       mergedSchemaUrl = _schemaUrl;
      80            0 :     } else if (_schemaUrl == other._schemaUrl) {
      81            0 :       mergedSchemaUrl = _schemaUrl;
      82              :     } else {
      83              :       // Schema URLs are different and non-empty - this is a merging error
      84              :       // The spec says the result is implementation-specific
      85              :       // We'll choose to use the updating resource's schema URL
      86            0 :       mergedSchemaUrl = other._schemaUrl;
      87              :     }
      88              : 
      89              :     final result =
      90           90 :         Resource._(OTel.attributesFromMap(mergedMap), mergedSchemaUrl);
      91              : 
      92           45 :     if (OTelLog.isDebug()) {
      93           45 :       OTelLog.debug('Resource merge result attributes:');
      94          180 :       result._attributes.toList().forEach((attr) {
      95          180 :         if (attr.key == 'tenant_id' || attr.key == 'service.name') {
      96          180 :           OTelLog.debug('  ${attr.key}: ${attr.value}');
      97              :         }
      98              :       });
      99              :     }
     100              : 
     101              :     return result;
     102              :   }
     103              : }