mapper

Documentation

Index

• Constants
• Variables
• func PrepareQuery(dialect string, rawSql []byte) (string, []interface{}, error)
• func RegisterEnums(enums map[string]map[string]int32)
• type Mapper
  • func New(name string, rows *db.Rows, protoResp interface{}) (*Mapper, error)
  • func (m *Mapper) GetValues(rows *db.Rows, respMap *ResponseMapping) error
  • func (m *Mapper) Log()
  • func (m *Mapper) MapResponse(respMap *ResponseMapping) error
  • func (m *Mapper) MapRow(rowValues []interface{}, sqlMap *SqlMap, sqlMapVals *SqlMapVals, ...)
  • func (m *Mapper) NewResponseMapping() *ResponseMapping
• type ProtoField
• type ResponseMapping
• type SqlMap
• type SqlMapVals
• type Value

Constants

const (
	TopLevelElement mapType = iota
	Association
	Collection
)

Map can either be, a top level element (proto response) Association, (nested field) or Collection, (repeated nested field)

Variables

var (
	EnumVals map[string]map[string]int32
)

Functions

func PrepareQuery

func PrepareQuery(dialect string, rawSql []byte) (string, []interface{}, error)

func RegisterEnums

func RegisterEnums(enums map[string]map[string]int32)

Types

type Mapper

type Mapper struct {
	SqlMap *SqlMap //Mapping of top level element, proto response message
	Name   string  //Name of the corresponding RPC
	Logs   map[string]bool
	Error  error
	// contains filtered or unexported fields
}

Representation of SQL response mapping to a proto response message protoc-gen-map generates service server methods which implement interfaces generated by protoc-gen-go each RPC and therefore SQL has corresponding Mapper

func New

func New(name string, rows *db.Rows, protoResp interface{}) (*Mapper, error)

Generates mapper instance based on proto response type and response of sql query This is done once after the first response is retrieved

func (*Mapper) GetValues

func (m *Mapper) GetValues(rows *db.Rows, respMap *ResponseMapping) error

Retrieves all values from the query

func (*Mapper) Log

func (m *Mapper) Log()

If non-breaking issues are found while mapping, this function prints them

func (*Mapper) MapResponse

func (m *Mapper) MapResponse(respMap *ResponseMapping) error

Begin mapping the proto response This is method is called for SQL query response

func (*Mapper) MapRow

func (m *Mapper) MapRow(rowValues []interface{}, sqlMap *SqlMap, sqlMapVals *SqlMapVals, protoMsg interface{}, uniqueId string)

Map a single row of the sql query This function starts with the top level element as input parameter, and is called recursively for each Association and Collection on the same row

func (*Mapper) NewResponseMapping

func (m *Mapper) NewResponseMapping() *ResponseMapping

Generates Response Mapping, an object which stores mapped SQL response values

type ProtoField

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

ProtoField represents one field in a proto struct generated by protoc-gen-go used to keep track of its location in the parent struct

type ResponseMapping

type ResponseMapping struct {
	// slice of Top Level Elements, pointers to response messages
	Responses []interface{}
	// contains filtered or unexported fields
}

Each RPC call generates ResponseMapping, this is responsible for storing data in structure matching the proto response

type SqlMap

type SqlMap struct {
	Name        mapName      // Name of the corresponging proto message
	MapType     mapType      //
	ProtoStruct reflect.Type // type of the corresponging proto message

	// ProtoStruct for Collections are slices of pointers,
	// if the SqlMap Type is a Collection, this field is the pointer of the underlyiogn struct
	// For top level element and association types, this field is nil
	ProtoSliceElem reflect.Type
	// For collections and association, this the i in reflect.Value.Field(i) where i is the ith field of the SqlMap
	// which corresponds to the Proto Message which holds this association or collection.
	ParentFieldId int

	// Column correspond to proto message field names that match sql columns
	Columns map[columnName]*ProtoField
	// Columns of the SQL response which are present in this proto message
	PresentColumns []string
	//  and those columns' values
	ProtoValues []interface{}

	// Associations are has-one relationships which correspond to nested proto messages
	Associations map[mapName]*SqlMap
	//Collections are has-many relationships which correspond to nested and repeated proto messages
	Collections map[mapName]*SqlMap

	Error error    // breaking issue
	Logs  []string // non-breaking issue
}

SqlMap stores types of proto messages and their corresponding column name if the proto message has repeated and/or nested fields, they are recursively stores in Associations and Collections

type SqlMapVals

type SqlMapVals struct {
	// Columns values of the SQL response which are present in this proto message
	// this field contained currently analysed values
	ProtoValues []interface{}

	// If all current ProtoValues are nil, isNil is set true and mapping of this element is omitted
	IsNill bool

	// Protoc-gen-map uses all present columns in a particular message to generate a unique id,
	// if successive rows have the same id, it identifies the same element
	// always include a uniquely identifiable column in your query
	//
	// interface{} in this map are pointers to response proto messages
	UniqueIds map[string]interface{}

	// Associations are has-one relationships which correspond to nested proto messages
	Associations map[mapName]*SqlMapVals
	//Collections are has-many relationships which correspond to nested and repeated proto messages
	Collections map[mapName]*SqlMapVals
}

SQL Values are values returned from the SQL query which belong to a particular proto message. Pointers to those messages are stored in UniqueIds

type Value

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