ddbpath

Documentation

Overview

Package ddbpath provides logic for building and parsing Dynamo document paths

Index

• Variables
• func Register(nb NameBuilder, fields map[string]FieldInfo)
• func SelectMapValues(v map[string]types.AttributeValue, paths ...string) (res map[string]types.AttributeValue, err error)
• func SelectValues(v types.AttributeValue, paths ...string) (res map[string]types.AttributeValue, err error)
• func Validate(nb NameBuilder, paths ...string) error
• type AnyPath
  • func (p AnyPath) TypeURL() expression.NameBuilder
  • func (p AnyPath) Value() expression.NameBuilder
  • func (p AnyPath) WithDynamoNameBuilder(n expression.NameBuilder) AnyPath
• type ErrFieldNotAllowed
  • func (e ErrFieldNotAllowed) Error() string
• type ErrIndexNotAllowed
  • func (e ErrIndexNotAllowed) Error() string
• type ErrTypeNotRegistered
  • func (e ErrTypeNotRegistered) Error() string
• type ErrUnknownField
  • func (e ErrUnknownField) Error() string
• type FieldInfo
  • func (fi FieldInfo) String() string
• type FieldKind
  • func (fi FieldKind) String() string
• type FieldMaskPath
  • func (p FieldMaskPath) Masks() List
  • func (p FieldMaskPath) WithDynamoNameBuilder(n expression.NameBuilder) FieldMaskPath
• type ItemList
  • func (p ItemList[T]) Index(i int) T
• type ItemMap
  • func (p ItemMap[T]) Key(k string) T
• type List
  • func (p List) Index(i int) expression.NameBuilder
• type Map
  • func (p Map) Key(k string) expression.NameBuilder
• type NameBuilder
• type PathElement
  • func AppendParsePath(p string, r []PathElement) ([]PathElement, error)
  • func ParsePath(p string) ([]PathElement, error)
• type Registry
  • func NewRegistry() Registry
  • func (r Registry) FieldsOf(nb NameBuilder) (fi map[string]FieldInfo, ok bool)
  • func (r Registry) Register(nb NameBuilder, fields map[string]FieldInfo)
  • func (r Registry) Traverse(nb NameBuilder, p string) (fi FieldInfo, flds map[string]FieldInfo, err error)
  • func (r Registry) Validate(nb NameBuilder, paths ...string) (err error)
• type ValuePath
  • func (p ValuePath) WithDynamoNameBuilder(n expression.NameBuilder) ValuePath

Variables

var NoInfo = FieldInfo{}

NoInfo is the FieldInfo zero value

Functions

func Register

func Register(nb NameBuilder, fields map[string]FieldInfo)

Register a generated name building struct with the default registry. It panics if the type is already registered.

func SelectMapValues

func SelectMapValues(v map[string]types.AttributeValue, paths ...string) (res map[string]types.AttributeValue, err error)

SelectMapValues is a convenient wrapper around SelectValues for the common scenario of selecting from map of attribute values.

func SelectValues

func SelectValues(v types.AttributeValue, paths ...string) (res map[string]types.AttributeValue, err error)

SelectValues will return a subset of a composite attribute value 'v' (maps or sets), specified by 'paths'. This is usefull when only part of a DynamoDB item is allowed or desired for an operation. For example when only the keys need to be selected, or a partial update is performed using a mask.

func Validate

func Validate(nb NameBuilder, paths ...string) error

Validate each path in 'paths' given the path naming struct 'nb' as the root message where the paths are started from agains the default registery.

Types

type AnyPath

type AnyPath struct{ expression.NameBuilder }

AnyPath is registered to support path validation into anypb structs

func (AnyPath) TypeURL

func (p AnyPath) TypeURL() expression.NameBuilder

TypeURL appends the path of the type url

func (AnyPath) Value

func (p AnyPath) Value() expression.NameBuilder

Value appends the path of the value

func (AnyPath) WithDynamoNameBuilder

func (p AnyPath) WithDynamoNameBuilder(n expression.NameBuilder) AnyPath

WithDynamoNameBuilder allows generic types to overwrite the path

type ErrFieldNotAllowed

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

func (ErrFieldNotAllowed) Error

func (e ErrFieldNotAllowed) Error() string

type ErrIndexNotAllowed

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

func (ErrIndexNotAllowed) Error

func (e ErrIndexNotAllowed) Error() string

type ErrTypeNotRegistered

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

ErrTypeNotRegistered is returned when a type is not registered in the registry being used

func (ErrTypeNotRegistered) Error

func (e ErrTypeNotRegistered) Error() string

type ErrUnknownField

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

func (ErrUnknownField) Error

func (e ErrUnknownField) Error() string

type FieldInfo

type FieldInfo struct {
	Kind    FieldKind    // list, map, basic, any etc
	Message reflect.Type // field holds a non-basic type, or nil if its a basic type
}

FieldInfo of a field on a message

func (FieldInfo) String

func (fi FieldInfo) String() string

String returns a human readable form of the field info

type FieldKind

type FieldKind int

FieldKind describes the kind of field

const (
	// FieldKindUndefined means the kind was unknown
	FieldKindUndefined FieldKind = iota
	// FiledKindSingle represents a single instance of something
	FieldKindSingle
	// FieldKindList means a list of something
	FieldKindList
	// FieldKindMap means a map of something
	FieldKindMap
)

func (FieldKind) String

func (fi FieldKind) String() string

String provides human readable form for the kind

type FieldMaskPath

type FieldMaskPath struct{ expression.NameBuilder }

FieldMaskPath is registered to support path validation of fieldmask

func (FieldMaskPath) Masks

func (p FieldMaskPath) Masks() List

Masks appends the path of the value

func (FieldMaskPath) WithDynamoNameBuilder

func (p FieldMaskPath) WithDynamoNameBuilder(n expression.NameBuilder) FieldMaskPath

WithDynamoNameBuilder allows generic types to overwrite the path

type ItemList

type ItemList[T interface {
	WithDynamoNameBuilder(expression.NameBuilder) T
}] struct{ expression.NameBuilder }

ItemList is a list of nested items

func (ItemList[T]) Index

func (p ItemList[T]) Index(i int) T

Index into a list of items

type ItemMap

type ItemMap[T interface {
	WithDynamoNameBuilder(expression.NameBuilder) T
}] struct{ expression.NameBuilder }

ItemMap is a list of nested items

func (ItemMap[T]) Key

func (p ItemMap[T]) Key(k string) T

Key into a list of items

type List

type List struct{ expression.NameBuilder }

List of basic type(s)

func (List) Index

func (p List) Index(i int) expression.NameBuilder

Index into a list of basic types

type Map

type Map struct{ expression.NameBuilder }

Map of basic type(s)

func (Map) Key

func (p Map) Key(k string) expression.NameBuilder

Key into a map of basic types

type NameBuilder

type NameBuilder interface {
	AppendName(field expression.NameBuilder) expression.NameBuilder
}

NameBuilder inteface is implemented by generated name building structs

type PathElement

type PathElement struct {
	Field string
	Index int
}

PathElement describes a part of the path. It is either an numeric index into a list (or set) or it is a string key into the field.

func AppendParsePath

func AppendParsePath(p string, r []PathElement) ([]PathElement, error)

AppendParsePath will parse path 'p' and append elements to 'r'. If 'r' is already allocated with enough space to hold all the parts of 'p' it will not allocate any additional memory on the heap.

func ParsePath

func ParsePath(p string) ([]PathElement, error)

ParsePath will parse 'p' in its elements and return them.

type Registry

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

Registry holds type information so validation of string paths can happen efficiently

func NewRegistry

func NewRegistry() Registry

NewRegistry inits an empty registry

func (Registry) FieldsOf

func (r Registry) FieldsOf(nb NameBuilder) (fi map[string]FieldInfo, ok bool)

FieldsOf returns field information of a name builder implementation

func (Registry) Register

func (r Registry) Register(nb NameBuilder, fields map[string]FieldInfo)

Register a name builder with the registry for efficient validation. It panics if the typ is already registered.

func (Registry) Traverse

func (r Registry) Traverse(nb NameBuilder, p string) (fi FieldInfo, flds map[string]FieldInfo, err error)

Traverse a message name builder 'nb' via path 'p' and return field info and any fields.

func (Registry) Validate

func (r Registry) Validate(nb NameBuilder, paths ...string) (err error)

Validate given the types in the registry

type ValuePath

type ValuePath struct{ expression.NameBuilder }

ValuePath is registered to support path validation into structpb's value fields. It has no fields but is special in that it will accept any path into it.

func (ValuePath) WithDynamoNameBuilder

func (p ValuePath) WithDynamoNameBuilder(n expression.NameBuilder) ValuePath

WithDynamoNameBuilder allows generic types to overwrite the path