2 Thrift IDL Support.

8.12

2 Thrift IDL Support.🔗ℹ

Support for Thrift format definitions

Examples:

> (require thrift
           thrift/idl/language)
> (define-thrift-namespace parquet)
> (define-thrift-enum
    parquet-type 0
    (boolean
     int32
     int64
     int96
     float
     double
     byte-array
     fixed-len-byte-arrary))
> (define-thrift-struct file-metadata
    ([1 version required type-int32]
     [2 schema required list-of schema-element]
     [3 num-rows required type-int64]
     [4 row-groups required list-of row-group]
     [5 key-value-metadata optional list-of key-value]
     [6 created-by optional type-string]
     [7 column-orders optional list-of column-order]))

2.1 Type System🔗ℹ

(require thrift/idl/common)

package: thrift

2.1.1 Core Types🔗ℹ

procedure
(type? v) → boolean?
v : any/c

value
type-stop : type?
value
type-void : type?
value
type-bool : type?
value
type-byte : type?
value
type-int8 : type?
value
type-double : type?
value
type-int16 : type?
value
type-int32 : type?
value
type-int64 : type?
value
type-string : type?
value
type-binary : type?
value
type-utf-7 : type?
value
type-struct : type?
value
type-map : type?
value
type-list : type?
value
type-set : type?
value
type-utf-8 : type?
value
type-utf-16 : type?

TBD

procedure
(integer->type n) → type?
n : exact-nonnegative-integer?
procedure
(type/decode d) → type?
d : decoder?
procedure
(type/names) → (listof string?)

TBD

2.1.2 Field Type Information🔗ℹ

procedure
(required-type? v) → boolean?
v : any/c

value
required-type-required : required-type?
value
required-type-optional : required-type?
value
required-type-default : required-type?

TBD

procedure
(integer->required-type n) → required-type?
n : exact-nonnegative-integer?
procedure
(required-type/decode d) → required-type?
d : decoder?
procedure
(required-type/names) → (listof string?)

TBD

procedure
(container-type? v) → boolean?
v : any/c

value
container-type-list-of : container-type?
value
container-type-set-of : container-type?
value
container-type-map-of : container-type?
value
container-type-none : container-type?

TBD

procedure
(integer->container-type n) → container-type?
n : exact-nonnegative-integer?
procedure
(container-type/decode d) → container-type?
d : decoder?
procedure
(container-type/names) → (listof string?)

TBD

struct
(struct thrift-field ( id
name
required
container
major-type
minor-type
position)
    #:mutable)
  id : identifier?
  name : string?
  required : symbol?
  container : symbol?
  major-type : symbol?
  minor-type : symbol?
  position : exact-nonnegative-integer?

TBD

2.2 IDL Language🔗ℹ

(require thrift/idl/language)

package: thrift

syntax
(define-thrift-namespace namespace)

namespace : string?

TBD

syntax
(define-thrift-enum id maybe-start value ...)

id = string?

maybe-start =
| exact-nonnegative-integer?

value-expr = identifier?
| [identifier? exact-nonnegative-integer?]

TBD

syntax
(define-thrift-struct [id string?] field ...)

field = (index name maybe-req maybe-con elem-type)
| (index name maybe-req map-of elem-type key-type)

maybe-required =
| required-type?

maybe-container =
| container-type?

   index : exact-nonnegative-integer?
   name : identifier?
   elem-type : identifier?
   key-type : identifier?

TBD

2.3 Code Generator🔗ℹ

(require thrift/idl/generator)

package: thrift

procedure
(process-file [ file-path
module-prefix
over-write?]) → void?
  file-path : string? = "."
  module-prefix : string? = ""
  over-write? : boolean? = #f

TBD

2.3.1 Command-Line Launcher🔗ℹ

The parquet/idl/generator module is also used to create a launcher, rthrift that wraps process-file to generate bindings for an IDL file from a Racket description.

rthrift [ <option> ... ] <file-path>

where <option> is one of

-v, --verbose : Compile with verbose messages

-V, --very-verbose : Compile with very verbose messages

-o <path>, --output-path <path> : Directory to write the output into

-m <module>, --module-prefix <module> : Prefix generated modules with a module path

-f, --force-overwrite : Over-write any existing files

--help, -h : Show this help

-- : Do not treat any remaining argument as a switch (at this level)

Multiple single-letter switches can be combined after one `-'; for

example: `-h-' is the same as `-h --'

To generate the files used in the module parquet, we use the following command.

$ rthrift -o parquet/generated -m parquet/generated parquet/format.rkt

This generates the following files, in the parquet/generated directory.

parquet.rkt - The core types, expanded, used by the following.
parquet-encode.rkt - All the encoder functions for the types above.
parquet-decode.rkt - All the decoder functions for the types above.
parquet.scrbl - Documentation for the three modules above.

1	Thrift for Racket Architecture
2	Thrift IDL Support.
3	Thrift Transport Support.
4	Thrift Protocol Support
5	Thrift Processor Support
6	License