spanvalue

package module
v0.1.9 Latest Latest
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 Go to latest Published: Mar 27, 2026 License: MIT Imports: 17 Imported by: 1

README

spanvalue

This package includes spanner.GenericValueColumn related functionality.

Documentation

Index

Constants

This section is empty.

Variables

View Source 
var ErrFallthrough = errors.New("fallthrough")
View Source 
var FormatJSONObjectStruct = NewJSONObjectStructFormatter(nil)

FormatJSONObjectStruct formats struct fields as a JSON object with nil namer. Unnamed struct fields produce empty-string keys, matching Spanner's own representation.

View Source 
var FormatTypedStruct = FormatStruct{
	FormatStructParen: formatTypedStructParen,
	FormatStructField: formatSimpleStructField,
}
View Source 
var LiteralFormatConfig = &FormatConfig{
	NullString:     nullStringUpperCase,
	FormatArray:    FormatOptionallyTypedArray,
	FormatStruct:   FormatTypedStruct,
	FormatNullable: formatNullableValueLiteral,
	FormatComplexPlugins: []FormatComplexFunc{
		FormatProtoAsCast,
		FormatEnumAsCast,
	},
}
View Source 
var SimpleFormatConfig = FormatConfig{
	NullString:  nullStringClientLib,
	FormatArray: FormatUntypedArray,
	FormatStruct: FormatStruct{
		FormatStructField: FormatTypelessStructField,
		FormatStructParen: FormatTupleStruct,
	},
	FormatNullable: formatNullableValueSimple,
}
View Source 
var SpannerCLICompatibleFormatConfig = FormatConfig{
	NullString:  nullStringUpperCase,
	FormatArray: FormatUntypedArray,
	FormatStruct: FormatStruct{
		FormatStructField: FormatSimpleStructField,
		FormatStructParen: FormatBracketStruct,
	},
	FormatNullable: FormatNullableSpannerCLICompatible,
}

Functions

func FormatBracketStruct 

func FormatBracketStruct(typ *sppb.Type, toplevel bool, fieldStrings []string) string

func FormatColumnLiteral 

func FormatColumnLiteral(value spanner.GenericColumnValue) (string, error)

func FormatColumnSpannerCLICompatible 

func FormatColumnSpannerCLICompatible(value spanner.GenericColumnValue) (string, error)

func FormatCompactArray added in v0.1.9 

func FormatCompactArray(_ *sppb.Type, _ bool, elemStrings []string) string

FormatCompactArray formats array elements without spaces between separators. Output: [elem1,elem2,elem3]

func FormatEnumAsCast 

func FormatEnumAsCast(formatter Formatter, value spanner.GenericColumnValue, toplevel bool) (string, error)

func FormatJSONSimpleValue added in v0.1.9 

func FormatJSONSimpleValue(_ Formatter, value spanner.GenericColumnValue, _ bool) (string, error)

FormatJSONSimpleValue is a FormatComplexFunc that formats all non-ARRAY, non-STRUCT types as valid JSON values. It never returns ErrFallthrough.

For most types, structpb.Value.MarshalJSON() produces the correct JSON representation (BOOL→true/false, FLOAT→number, STRING→"quoted", NULL→null, NaN/Inf→"NaN"/"Infinity"). Only INT64, ENUM, and JSON columns need special handling:

  • INT64: Spanner encodes as StringValue("42"), MarshalJSON() would produce "42" (quoted), but we want 42 (unquoted number).
  • ENUM: Spanner stores proto enum values as INT64; same handling as INT64.
  • JSON: Spanner encodes as StringValue('{"key":"value"}'), MarshalJSON() would produce escaped quoted string, but we want the raw JSON value passed through.

func FormatNullableSpannerCLICompatible 

func FormatNullableSpannerCLICompatible(value NullableValue) (string, error)

func FormatOptionallyTypedArray 

func FormatOptionallyTypedArray(typ *sppb.Type, toplevel bool, elemStrings []string) string

func FormatProtoAsCast 

func FormatProtoAsCast(formatter Formatter, value spanner.GenericColumnValue, toplevel bool) (string, error)

func FormatRowJSONObject added in v0.1.9 

func FormatRowJSONObject(fc *FormatConfig, row *spanner.Row, namer UnnamedFieldNamer) (string, error)

FormatRowJSONObject formats a spanner.Row as a single JSON object string using the given FormatConfig for value formatting and column names as keys. The FormatConfig must produce standalone JSON values per column (e.g., JSONFormatConfig()). Using a non-JSON config produces syntactically invalid output. Empty column names (e.g., from expressions without aliases like SELECT 1+1) are assigned names by the provided namer function. If namer is nil, empty names are kept as empty-string JSON keys. Output: {"col1":val1,"col2":val2,...}

func FormatRowLiteral 

func FormatRowLiteral(value *spanner.Row) ([]string, error)

func FormatRowSpannerCLICompatible 

func FormatRowSpannerCLICompatible(row *spanner.Row) ([]string, error)

func FormatSimpleStructField 

func FormatSimpleStructField(fc *FormatConfig, field *sppb.StructType_Field, value *structpb.Value) (string, error)

func FormatTupleStruct 

func FormatTupleStruct(typ *sppb.Type, toplevel bool, fieldStrings []string) string

func FormatTypelessStructField 

func FormatTypelessStructField(fc *FormatConfig, field *sppb.StructType_Field, value *structpb.Value) (string, error)

func FormatUntypedArray 

func FormatUntypedArray(_ *sppb.Type, _ bool, elemStrings []string) string

func IndexedUnnamedFieldNamer added in v0.1.9 

func IndexedUnnamedFieldNamer(index int) string

IndexedUnnamedFieldNamer produces names like "_0", "_1", etc. The underscore prefix minimizes collision with user-defined names. Suitable for row columns (e.g., SELECT 1+1 produces "_0").

Types

type FormatArrayFunc 

type FormatArrayFunc func(typ *sppb.Type, toplevel bool, elemStrings []string) string

type FormatComplexFunc 

type FormatComplexFunc = func(formatter Formatter, value spanner.GenericColumnValue, toplevel bool) (string, error)

FormatComplexFunc is a function to format spanner.GenericColumnValue. If it returns ErrFallthrough, value will pass through to next step.

type FormatConfig 

type FormatConfig struct {
	NullString           string
	FormatArray          FormatArrayFunc
	FormatStruct         FormatStruct
	FormatComplexPlugins []FormatComplexFunc
	FormatNullable       FormatNullableFunc
}

func JSONFormatConfig added in v0.1.9 

func JSONFormatConfig() *FormatConfig

JSONFormatConfig returns a new FormatConfig that produces valid JSON value strings for each Spanner value. Each call returns a fresh instance that the caller may customize.

Each formatted string is a standalone JSON value:

  • NULL → null
  • BOOL → true / false
  • INT64 → 42 (unquoted number)
  • FLOAT32/FLOAT64 → 3.14 (NaN/Inf as quoted strings)
  • ENUM → 42 (unquoted number, Spanner stores proto enum values as INT64)
  • STRING, BYTES, TIMESTAMP, DATE, NUMERIC, PROTO, INTERVAL, UUID → "quoted string"
  • JSON column → raw JSON value (passed through)
  • ARRAY → [elem1,elem2,...]
  • STRUCT → {"field1":val1,"field2":val2,...}

func (*FormatConfig) FormatColumn 

func (fc *FormatConfig) FormatColumn(value spanner.GenericColumnValue, toplevel bool) (string, error)

func (*FormatConfig) FormatRow 

func (fc *FormatConfig) FormatRow(row *spanner.Row) ([]string, error)

func (*FormatConfig) FormatToplevelColumn 

func (fc *FormatConfig) FormatToplevelColumn(value spanner.GenericColumnValue) (string, error)

type FormatNullableFunc 

type FormatNullableFunc = func(value NullableValue) (string, error)

type FormatStruct 

type FormatStruct struct {
	FormatStructField FormatStructFieldFunc
	FormatStructParen FormatStructParenFunc
}

type FormatStructFieldFunc 

type FormatStructFieldFunc func(fc *FormatConfig, field *sppb.StructType_Field, value *structpb.Value) (string, error)

type FormatStructParenFunc 

type FormatStructParenFunc func(typ *sppb.Type, toplevel bool, fieldStrings []string) string

func NewJSONObjectStructFormatter added in v0.1.9 

func NewJSONObjectStructFormatter(namer UnnamedFieldNamer) FormatStructParenFunc

NewJSONObjectStructFormatter creates a FormatStructParenFunc that formats struct fields as a JSON object with field names as keys. Unnamed fields are assigned names by the provided namer function. If namer is nil, unnamed fields keep empty-string keys (which produces duplicate keys — valid per RFC 8259 but may cause issues with parsers that deduplicate keys). Panics if a non-nil namer returns the same name for different indices (contract violation). Output: {"field1":val1,"field2":val2,...}

type Formatter 

type Formatter interface {
	FormatColumn(value spanner.GenericColumnValue, toplevel bool) (string, error)
}

type NullBytes 

type NullBytes []byte

func (NullBytes) IsNull 

func (n NullBytes) IsNull() bool

func (NullBytes) String 

func (n NullBytes) String() string

type NullableValue 

type NullableValue interface {
	spanner.NullableValue
	fmt.Stringer
}

type UnnamedFieldNamer added in v0.1.9 

type UnnamedFieldNamer func(index int) string

UnnamedFieldNamer generates a name for an unnamed field or column. The index argument is a monotonically increasing counter (not necessarily the field's positional index) that may skip values due to collision avoidance. It must return distinct non-empty names for distinct indices. Functions that accept UnnamedFieldNamer (such as NewJSONObjectStructFormatter and FormatRowJSONObject) panic if the namer violates this contract. Pass nil instead of a namer to keep unnamed fields as empty-string keys.

Source Files

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