grpcdatasource

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Published: Nov 10, 2025 License: MIT Imports: 27 Imported by: 1

Documentation

Overview

Package grpcdatasource provides a GraphQL datasource implementation for gRPC services. It allows GraphQL servers to connect to gRPC backends and execute RPC calls as part of GraphQL query resolution.

The package includes tools for parsing Protobuf definitions, building execution plans, and converting GraphQL queries into gRPC requests.

Index

Constants

View Source
const (
	// InvalidRef is a constant used to indicate that a reference is invalid.
	InvalidRef = -1
)

Variables

This section is empty.

Functions

This section is empty.

Types

type CallKind

type CallKind int

CallKind is the type of call operation to perform.

const (
	// CallKindStandard is a basic fetch operation.
	CallKindStandard CallKind = iota
	// CallKindEntity is a fetch operation for entities.
	CallKindEntity
	// CallKindResolve is a fetch operation for resolving field values.
	CallKindResolve
)

type DataSource

type DataSource struct {
	// contains filtered or unexported fields
}

DataSource implements the resolve.DataSource interface for gRPC services. It handles the conversion of GraphQL queries to gRPC requests and transforms the responses back to GraphQL format.

func NewDataSource

func NewDataSource(client grpc.ClientConnInterface, config DataSourceConfig) (*DataSource, error)

NewDataSource creates a new gRPC datasource

func (*DataSource) Load

func (d *DataSource) Load(ctx context.Context, input []byte, out *bytes.Buffer) (err error)

Load implements resolve.DataSource interface. It processes the input JSON data to make gRPC calls and writes the response to the output buffer.

The input is expected to contain the necessary information to make a gRPC call, including service name, method name, and request data.

func (*DataSource) LoadWithFiles

func (d *DataSource) LoadWithFiles(ctx context.Context, input []byte, files []*httpclient.FileUpload, out *bytes.Buffer) (err error)

LoadWithFiles implements resolve.DataSource interface. Similar to Load, but handles file uploads if needed.

Note: File uploads are typically not part of gRPC, so this method might not be applicable for most gRPC use cases.

Currently unimplemented.

type DataSourceConfig

type DataSourceConfig struct {
	Operation         *ast.Document
	Definition        *ast.Document
	Compiler          *RPCCompiler
	SubgraphName      string
	Mapping           *GRPCMapping
	FederationConfigs plan.FederationFieldConfigurations
	Disabled          bool
}

type DataType

type DataType string

DataType represents the different types of data that can be stored in a protobuf field.

const (
	DataTypeString  DataType = "string"    // String type
	DataTypeInt32   DataType = "int32"     // 32-bit integer type
	DataTypeInt64   DataType = "int64"     // 64-bit integer type
	DataTypeUint32  DataType = "uint32"    // 32-bit unsigned integer type
	DataTypeUint64  DataType = "uint64"    // 64-bit unsigned integer type
	DataTypeFloat   DataType = "float"     // 32-bit floating point type
	DataTypeDouble  DataType = "double"    // 64-bit floating point type
	DataTypeBool    DataType = "bool"      // Boolean type
	DataTypeEnum    DataType = "enum"      // Enumeration type
	DataTypeMessage DataType = "message"   // Nested message type
	DataTypeUnknown DataType = "<unknown>" // Represents an unknown or unsupported type
	DataTypeBytes   DataType = "bytes"     // Bytes type
)

Protobuf data types supported by the compiler.

func (DataType) IsValid

func (d DataType) IsValid() bool

IsValid checks if the DataType is a valid protobuf type.

func (DataType) String

func (d DataType) String() string

String returns the string representation of the DataType.

type DependencyGraph

type DependencyGraph struct {
	// contains filtered or unexported fields
}

DependencyGraph is a graph of the calls in the execution plan. It is used to determine the order in which to execute the calls.

func NewDependencyGraph

func NewDependencyGraph(executionPlan *RPCExecutionPlan) *DependencyGraph

func (*DependencyGraph) Fetch

func (g *DependencyGraph) Fetch(index int) (FetchItem, error)

Fetch returns the fetch item for a given index.

func (*DependencyGraph) FetchDependencies

func (g *DependencyGraph) FetchDependencies(fetch *FetchItem) ([]FetchItem, error)

FetchDependencies returns the dependencies for a given fetch item.

func (*DependencyGraph) SetFetchData

func (g *DependencyGraph) SetFetchData(index int, serviceCall *ServiceCall)

SetFetchData sets the service call for a given index.

func (*DependencyGraph) TopologicalSortResolve

func (g *DependencyGraph) TopologicalSortResolve(resolver func(nodes []FetchItem) error) error

TopologicalSortResolve sorts the calls in the execution plan in a topological order. In order to perform calls in the correct order, we need to determine the dependencies between the calls. We are using a depth-first search to determine the dependencies between the calls by building an index map of the call hierarchy. Each index in the index map corresponds to a call index in the execution plan. The map contains the level of the call in the hierarchy. The root call has a level of 0.

type Document

type Document struct {
	Package  string    // The package name of the protobuf document
	Imports  []string  // The imports of the protobuf document
	Services []Service // All services defined in the document
	Enums    []Enum    // All enums defined in the document
	Messages []Message // All messages defined in the document
	Methods  []Method  // All methods from all services in the document
	// contains filtered or unexported fields
}

Document represents a compiled protobuf document with all its services, messages, and methods.

func (*Document) EnumByName

func (d *Document) EnumByName(name string) (Enum, bool)

EnumByName returns an Enum by its name. Returns false if the enum does not exist.

func (*Document) MessageByName

func (d *Document) MessageByName(name string) (Message, bool)

MessageByName returns a Message by its name. Returns an empty Message if no message with the given name exists. We only expect this function to return false if either the message name was provided incorrectly, or the schema and mapping was not properly configured.

func (*Document) MessageByRef

func (d *Document) MessageByRef(ref int) Message

MessageByRef returns a Message by its reference index.

func (*Document) MessageRefByName

func (d *Document) MessageRefByName(name string) int

MessageRefByName returns the index of a Message in the Messages slice by its name. Returns -1 if no message with the given name exists.

func (*Document) ServiceByName

func (d *Document) ServiceByName(name string) *Service

ServiceByName returns a Service by its name. Returns an empty Service if no service with the given name exists.

type EntityRPCConfig

type EntityRPCConfig struct {
	// RPCConfig is the embedded configuration for the RPC operation
	RPCConfig

	// Key is a list of field names that uniquely identify the entity
	Key string
}

EntityRPCConfig defines the configuration for entity lookups

type Enum

type Enum struct {
	Name   string      // The name of the enum
	Values []EnumValue // The values in the enum
}

Enum represents a protobuf enum type with its values.

type EnumValue

type EnumValue struct {
	Name         string // The name of the enum value
	GraphqlValue string // The target value of the enum value
	Number       int32  // The numeric value of the enum value
}

EnumValue represents a single value in a protobuf enum.

type EnumValueMapping

type EnumValueMapping struct {
	Value       string // The GraphQL enum value
	TargetValue string // The gRPC enum value
}

EnumValueMapping defines the mapping between a GraphQL enum value and a gRPC enum value

type FetchItem

type FetchItem struct {
	ID               int
	Plan             *RPCCall
	ServiceCall      *ServiceCall
	DependentFetches []int
}

FetchItem is a single fetch item in the execution plan. It contains the call information, the service call, and a list of references to the dependent fetches.

type Field

type Field struct {
	Name       string   // The name of the field
	Type       DataType // The data type of the field
	Number     int32    // The field number in the protobuf message
	Ref        int      // Reference to the field (used for complex types)
	Repeated   bool     // Whether the field is a repeated field (array/list)
	Optional   bool     // Whether the field is optional
	MessageRef int      // If the field is a message type, this points to the message definition
}

Field represents a field in a protobuf message.

func (*Field) IsMessage

func (f *Field) IsMessage() bool

func (*Field) ResolveUnderlyingMessage

func (f *Field) ResolveUnderlyingMessage(doc *Document) *Message

type FieldArgumentMap

type FieldArgumentMap map[string]string

FieldArgumentMap defines the mapping between a GraphQL field argument and a gRPC field

type FieldMap

type FieldMap map[string]FieldMapData

FieldMap defines the mapping between a GraphQL field and a gRPC field The key is the field name in the GraphQL type. The value is the FieldMapData for that field which contains the target name and the argument mappings.

type FieldMapData

type FieldMapData struct {
	TargetName       string           // The name of the gRPC field
	ArgumentMappings FieldArgumentMap // The mapping between GraphQL field arguments and gRPC request arguments
}

FieldMapData defines the mapping between a GraphQL field and a gRPC field

type GRPCConfiguration

type GRPCConfiguration struct {
	Disabled bool         // Whether the RPC is disabled
	Mapping  *GRPCMapping // The mapping between GraphQL types and gRPC messages
	Compiler *RPCCompiler // The compiler for the RPC
}

GRPCConfiguration defines the configuration for a gRPC datasource

type GRPCMapping

type GRPCMapping struct {
	// Service is the name of the gRPC service to use
	Service string
	// QueryRPCs maps GraphQL query fields to the corresponding gRPC RPC configurations
	QueryRPCs RPCConfigMap[RPCConfig]
	// MutationRPCs maps GraphQL mutation fields to the corresponding gRPC RPC configurations
	MutationRPCs RPCConfigMap[RPCConfig]
	// SubscriptionRPCs maps GraphQL subscription fields to the corresponding gRPC RPC configurations
	SubscriptionRPCs RPCConfigMap[RPCConfig]
	// ResolveRPCs maps GraphQL resolve fields to the corresponding gRPC RPC configurations
	ResolveRPCs RPCConfigMap[ResolveRPCMapping]
	// EntityRPCs defines how GraphQL types are resolved as entities using specific RPCs
	// The key is the type name and the value is a list of EntityRPCConfig for that type
	EntityRPCs map[string][]EntityRPCConfig
	// Fields defines the field mappings between GraphQL types and gRPC messages
	// The key is the type name and the value is a map of field name to FieldMapData for that type
	Fields map[string]FieldMap
	// EnumValues defines the enum values for each enum type
	// The key is the enum type name and the value is a list of EnumValueMapping for that enum type
	EnumValues map[string][]EnumValueMapping
}

func (*GRPCMapping) FindEntityRPCConfig

func (g *GRPCMapping) FindEntityRPCConfig(typeName, key string) (RPCConfig, bool)

FindEntityRPCConfig finds the gRPC RPC config for a given GraphQL type and key

func (*GRPCMapping) FindEnumValueMapping

func (g *GRPCMapping) FindEnumValueMapping(enumName, enumValue string) (string, bool)

FindEnumValueMapping finds the gRPC enum value for a given GraphQL enum value

func (*GRPCMapping) FindFieldArgumentMapping

func (g *GRPCMapping) FindFieldArgumentMapping(typeName, fieldName, argumentName string) (string, bool)

FindFieldArgumentMapping finds the gRPC field name for a given GraphQL field name and argument name

func (*GRPCMapping) FindFieldMapping

func (g *GRPCMapping) FindFieldMapping(typeName string, fieldName string) (string, bool)

FindFieldMapping finds the gRPC field name for a given GraphQL field name and type

func (*GRPCMapping) FindResolveTypeFieldMapping

func (g *GRPCMapping) FindResolveTypeFieldMapping(typeName, fieldName string) *ResolveRPCTypeField

FindResolveTypeFieldMapping finds the gRPC field name for a given GraphQL field name and type

type LevelInfo

type LevelInfo struct {
	// Optional indicates if the field is optional
	Optional bool
}

LevelInfo contains the metadata for the list type

type ListMetadata

type ListMetadata struct {
	// NestingLevel is the nesting level of the list type
	NestingLevel int
	// LevelInfo contains the metadata for each nesting level of the list
	LevelInfo []LevelInfo
}

ListMetadata contains the metadata for the list type

type Message

type Message struct {
	Fields map[uint64]Field
	Name   string                     // The name of the message
	Desc   protoref.MessageDescriptor // The protobuf descriptor for the message
}

Message represents a protobuf message type with its fields.

func (*Message) AllocFields

func (m *Message) AllocFields(count int)

AllocFields allocates a new map of fields with the given count.

func (*Message) GetField

func (m *Message) GetField(name string) *Field

GetField returns a field by its name. Returns nil if no field with the given name exists.

func (*Message) SetField

func (m *Message) SetField(f Field)

type Method

type Method struct {
	Name       string // The name of the method
	InputName  string // The name of the input message type
	InputRef   int    // Reference to the input message in the Document.Messages slice
	OutputName string // The name of the output message type
	OutputRef  int    // Reference to the output message in the Document.Messages slice
}

Method represents a gRPC method with input and output message types.

type NodeKind

type NodeKind int
const (
	NodeKindMessage NodeKind = iota + 1
	NodeKindEnum
	NodeKindService
	NodeKindUnknown
)

type OneOfType

type OneOfType uint8

OneOfType represents the type of a oneof field in a protobuf message. It can be either an interface or a union type.

const (
	// OneOfTypeNone represents no oneof type (default/zero value)
	OneOfTypeNone OneOfType = iota
	// OneOfTypeInterface represents an interface type oneof field
	OneOfTypeInterface
	// OneOfTypeUnion represents a union type oneof field
	OneOfTypeUnion
)

OneOfType constants define the different types of oneof fields.

func (OneOfType) FieldName

func (o OneOfType) FieldName() string

FieldName returns the corresponding field name for the OneOfType. For interfaces, it returns "instance", for unions it returns "value". Returns an empty string for invalid or unknown types.

type PlanVisitor

type PlanVisitor interface {
	PlanOperation(operation, definition *ast.Document) (*RPCExecutionPlan, error)
}

func NewPlanner

func NewPlanner(subgraphName string, mapping *GRPCMapping, federationConfigs plan.FederationFieldConfigurations) (PlanVisitor, error)

NewPlanner returns a new PlanVisitor instance.

The planner is responsible for creating an RPCExecutionPlan from a given GraphQL operation. It is used by the engine to execute operations against gRPC services.

type ProtoConfig

type ProtoConfig struct {
	Schema string
}

type RPCCall

type RPCCall struct {
	// Kind of call, used to decide how to execute the call
	// This is used to identify the call type and execution behaviour.
	Kind CallKind
	// DependentCalls is a list of calls that must be executed before this call
	DependentCalls []int
	// ServiceName is the name of the gRPC service to call
	ServiceName string
	// MethodName is the name of the method on the service to call
	MethodName string
	// Request contains the message structure for the gRPC request
	Request RPCMessage
	// Response contains the message structure for the gRPC response
	Response RPCMessage
	// ResponsePath is the path to the response in the JSON response
	ResponsePath ast.Path
}

RPCCall represents a single call to a gRPC service method. It contains all the information needed to make the call and process the response.

type RPCCompiler

type RPCCompiler struct {
	Ancestor []Message
	// contains filtered or unexported fields
}

RPCCompiler compiles protobuf schema strings into a Document and can build protobuf messages from JSON data based on the schema.

func NewProtoCompiler

func NewProtoCompiler(schema string, mapping *GRPCMapping) (*RPCCompiler, error)

NewProtoCompiler compiles the protobuf schema into a Document structure. It extracts information about services, methods, messages, and enums from the protobuf schema.

func (*RPCCompiler) CompileFetches

func (p *RPCCompiler) CompileFetches(graph *DependencyGraph, fetches []FetchItem, inputData gjson.Result) ([]ServiceCall, error)

func (*RPCCompiler) CompileNode

func (p *RPCCompiler) CompileNode(graph *DependencyGraph, fetch FetchItem, inputData gjson.Result) (ServiceCall, error)

type RPCConfig

type RPCConfig struct {
	// RPC is the name of the RPC method to call
	RPC string
	// Request is the name of the request message type
	Request string
	// Response is the name of the response message type
	Response string
}

RPCConfig defines the configuration for a specific RPC operation

type RPCConfigMap

type RPCConfigMap[T RPCMapping] map[string]T

RPCConfigMap is a map of RPC names to RPC configurations The key is the field name in the GraphQL operation type (query, mutation, subscription). The value is the RPC configuration for that field.

type RPCExecutionPlan

type RPCExecutionPlan struct {
	// Calls is a list of gRPC calls that are executed in the same group
	Calls []RPCCall
}

RPCExecutionPlan represents a plan for executing one or more RPC calls to gRPC services. It defines the sequence of calls and their dependencies.

func (*RPCExecutionPlan) String

func (r *RPCExecutionPlan) String() string

type RPCField

type RPCField struct {
	// Alias can be used to rename the field in the request message
	// This is needed to make sure that during the json composition,
	// the field names match the GraphQL request naming.
	Alias string
	// Repeated indicates if the field is a repeated field (array/list)
	Repeated bool
	// Name is the name of the field as defined in the protobuf message
	Name string
	// ProtoTypeName is the name of the type of the field in the protobuf definition
	ProtoTypeName DataType
	// JSONPath either holds the path to the variable definition for the request message,
	// or defines the name of the response field in the message.
	JSONPath string
	// ResolvePath is used to resolve values from another message.
	ResolvePath ast.Path
	// EnumName is the name of the enum if the field is an enum type
	EnumName string
	// StaticValue is the static value of the field
	StaticValue string
	// Optional indicates if the field is optional
	Optional bool
	// IsListType indicates if the field is a list wrapper type
	IsListType bool
	// ListMetadata contains the metadata for the list type
	ListMetadata *ListMetadata
	// Message represents the nested message type definition for complex fields.
	// This enables recursive construction of nested protobuf message structures.
	Message *RPCMessage
}

RPCField represents a single field in a gRPC message. It contains all information required to extract data from GraphQL variables and construct the appropriate protobuf field.

func (*RPCField) AliasOrPath

func (r *RPCField) AliasOrPath() string

AliasOrPath returns the alias of the field if it exists, otherwise it returns the JSONPath.

func (*RPCField) IsOptionalScalar

func (r *RPCField) IsOptionalScalar() bool

IsOptionalScalar checks if the field is an optional scalar value.

func (*RPCField) ToOptionalTypeMessage

func (r *RPCField) ToOptionalTypeMessage(protoName string) *RPCMessage

ToOptionalTypeMessage returns a message that wraps the scalar value in a message as protobuf scalar types are not nullable.

type RPCFieldSelectionSet

type RPCFieldSelectionSet map[string]RPCFields

RPCFieldSelectionSet is a map of field selections based on inline fragments

func (RPCFieldSelectionSet) Add

func (r RPCFieldSelectionSet) Add(fragmentName string, field RPCField)

Add adds a field selection set to the map

func (RPCFieldSelectionSet) SelectFieldsForTypes

func (r RPCFieldSelectionSet) SelectFieldsForTypes(validTypes []string) RPCFields

SelectFieldsForTypes returns the fields for the given valid types. It also makes sure to deduplicate the fields.

type RPCFields

type RPCFields []RPCField

RPCFields is a list of RPCFields that provides helper methods for working with collections of fields.

func (RPCFields) ByName

func (r RPCFields) ByName(name string) *RPCField

ByName returns a field by its name from the collection of fields. Returns nil if no field with the given name exists.

func (RPCFields) Exists

func (r RPCFields) Exists(name, alias string) bool

Exists checks if a field with the given name and alias exists in the collection of fields.

type RPCMapping

type RPCMapping interface {
	RPCConfig | ResolveRPCMapping
}

LookupFieldMapDefinition defines the mapping between a GraphQL field and a gRPC field

type RPCMessage

type RPCMessage struct {
	// Name is the name of the message type in the protobuf definition
	Name string
	// Fields is a list of fields in the message
	Fields RPCFields
	// FieldSelectionSet are field selections based on inline fragments
	FieldSelectionSet RPCFieldSelectionSet
	// OneOfType indicates the type of the oneof field
	OneOfType OneOfType
	// MemberTypes provides the names of the types that are implemented by the Interface or Union
	MemberTypes []string
	// Message represents the nested message type definition for complex fields.
	// This enables recursive construction of nested protobuf message structures.
	Message *RPCMessage
}

RPCMessage represents a gRPC message structure for requests and responses. It defines the structure of the message including all its fields.

func (*RPCMessage) AppendTypeNameField

func (r *RPCMessage) AppendTypeNameField(typeName string)

AppendTypeNameField appends a typename field to the message.

func (*RPCMessage) IsOneOf

func (r *RPCMessage) IsOneOf() bool

IsOneOf checks if the message is a oneof field.

func (*RPCMessage) SelectValidTypes

func (r *RPCMessage) SelectValidTypes(typeName string) []string

SelectValidTypes returns the valid types for a given type name.

type ResolveRPCMapping

type ResolveRPCMapping map[string]ResolveRPCTypeField

ResolveRPCMapping defines the mapping between a GraphQL field resolver and a gRPC RPC configuration

type ResolveRPCTypeField

type ResolveRPCTypeField struct {
	FieldMappingData FieldMapData // The mapping between GraphQL field arguments and gRPC request arguments
	RPC              string       // The name of the RPC method to call
	Request          string       // The name of the request message type
	Response         string       // The name of the response message type
}

ResolveRPCTypeField defines the mapping between a GraphQL resolve field and a gRPC RPC configuration

type Service

type Service struct {
	Name        string // The name of the service
	FullName    string // The full name of the service
	MethodsRefs []int  // References to methods in the Document.Methods slice
}

Service represents a gRPC service with methods.

type ServiceCall

type ServiceCall struct {
	// ServiceName is the name of the gRPC service to call
	ServiceName string
	// MethodName is the name of the method on the service to call
	MethodName string
	// Input is the input message for the gRPC call
	Input protoref.Message
	// Output is the output message for the gRPC call
	Output protoref.Message
	// RPC is the call that was made to the gRPC service
	RPC *RPCCall
}

ServiceCall represents a single gRPC service call with its input and output messages.

func (*ServiceCall) MethodFullName

func (s *ServiceCall) MethodFullName() string

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