Nevinitsin Yury > MR-Tarantool > MR::Tarantool::Box

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NAME ^

MR::Tarantool::Box - A driver for an efficient Tarantool/Box NoSQL in-memory storage.

SYNOPSIS ^

    my $box = MR::Tarantool::Box->new({
        servers => "127.0.0.1:33013",
        name    => "My Box",              # mostly used for debug purposes
        spaces => [ {
            indexes => [ {
                index_name   => 'idx1',
                keys         => [0],
            }, {
                index_name   => 'idx2',
                keys         => [1,2],
            }, ],
            space         => 1,               # space id, as set in Tarantool/Box config
            name          => "primary",       # self-descriptive space-id
            format        => "QqLlSsCc&$",    # pack()-compatible, Qq must be supported by perl itself,
                                              # & stands for byte-string, $ stands for utf8 string.
            default_index => 'idx1',
            fields        => [qw/ id f2 field3 f4 f5 f6 f7 f8 misc_string /], # turn each tuple into hash, field names according to format
        }, {
            #...
        } ],
        default_space => "primary",

        timeout   => 1.0,                 # seconds
        retry     => 3,
        debug     => 9,                   # output to STDERR some debugging info
        raise     => 0,                   # dont raise an exception in case of error
    });

    my $bool  = $box->Insert(1, 2,3, 4,5,6,7,8,"asdf")                            or die $box->ErrorStr;
    my $bool  = $box->Insert(2, 2,4, 4,5,6,7,8,"asdf",{space => "primary"})       or die $box->ErrorStr;
    my $tuple = $box->Insert(3, 3,3, 4,5,6,7,8,"asdf",{want_inserted_tuple => 1}) or die $box->ErrorStr;

    # Select by single-field key
    my $tuple  = $box->Select(1);                                                 # scalar context - scalar result: $tuple
    my @tuples = $box->Select(1,2,3);                                             # list   context - list   result: ($tuple, $tuple, ...)
    my $tuples = $box->Select([1,2,3],{space => "primary", use_index => "idx1"}); #                arrayref result: [$tuple, $tuple, ...]

    # Select by multi-field key
    my $tuples = $box->Select([[2,3]],{use_index => "idx2"}); # by full key
    my $tuples = $box->Select([[2]]  ,{use_index => "idx2"}); # by partial key

    my $bool  = $box->UpdateMulti(1,[ f4 => add => 3 ]);
    my $bool  = $box->UpdateMulti(2,[ f4 => add => 3 ],{space => "primary"});
    my $tuple = $box->UpdateMulti(3,[ f4 => add => 3 ],{want_updated_tuple => 1});

    my $bool  = $box->Delete(1);
    my $tuple = $box->Delete(2, {want_deleted_tuple => 1});

DESCRIPTION ^

METHODS

new

    my $box = $class->new(\%args);

%args:

spaces => [ \%space, ... ]

%space:

space => $space_id_uint32

Space id as set in Tarantool/Box config.

name => $space_name_string

Self-descriptive space id, which will be mapped into space.

format => $format_string

pack()-compatible tuple format string, allowed formats: QqLlSsC(c&$)*, where & stands for bytestring, $ stands for "utf8" string. Qq usable only if perl supports int64 itself. Tuples' fields are packed/unpacked according to this format. * at the end of format enables "LongTuple".

hashify => $coderef

Specify a callback to turn each tuple into a good-looking hash. It receives space id and resultset as arguments. No return value needed.

    $coderef = sub {
        my ($space_id, $resultset) = @_;
        $_ = { FieldName1 => $_->[0], FieldName2 => $_->[1], ... } for @$resultset;
    };
fields => $arrayref

Specify an arrayref of fields names according to format to turn each tuple into a good-looking hash. Names must begin with [A-Za-z]. If "LongTuple" enabled, last field will be used to fold tailing fields.

long_fields => $arrayref

Specify an arrayref of fields names according to (xxx)* to turn tailing fields into a good-looking array of hashes. Names must begin with [A-Za-z]. Works with "LongTuple" enabled only.

indexes => [ \%index, ... ]

%index:

id => $index_id_uint32

Index id as set in Tarantool/Box config within current space. If not set, order position in indexes is theated as id.

name => $index_name_string

Self-descriptive index id, which will be mapped into index_id.

keys => [ $field_no_uint32, ... ]

Properly ordered arrayref of fields' numbers which are indexed.

default_index => $default_index_name_string_or_id_uint32

Index id or name to be used by default for the current space in select operations. Must be set if there are more than one \%indexes.

primary_key_index => $primary_key_name_string_or_id_uint32

Index id or name to be used by default for the current space in update operations. It is set to default_index by default.

default_space => $default_space_name_string_or_id_uint32

Space space or name to be used by default. Must be set if there are more than one \%spaces.

timeout => $timeout_fractional_seconds_float || 23

A common timeout for network operations.

select_timeout => $select_timeout_fractional_seconds_float || 2

Select queries timeout for network operations. See "select_retry".

retry => $retry_int || 1

A common retries number for network operations.

select_retry => $select_retry_int || 3

Select queries retries number for network operations.

Sometimes we need short timeout for select's and long timeout for critical update's, because in case of timeout we don't know if the update has succeeded. For the same reason we can't retry update operation.

So increasing timeout and setting retry => 1 for updates lowers possibility of such situations (but, of course, does not exclude them at all), and guarantees that we dont do the same more then once.

soft_retry => $soft_retry_int || 3

A common retries number for Tarantool/Box temporary errors (these marked by 1 in the lowest byte of error_code). In that case we know for sure that the request was declined by Tarantool/Box for some reason (a tuple was locked for another update, for example), and we can try it again.

This is also limited by retry/select_retry (depending on query type).

retry_delay => $retry_delay_fractional_seconds_float || 1

Specify a delay between retries for network operations.

raise => $raise_bool || 1

Should we raise an exceptions? If so, exceptions are raised when no more retries left and all tries failed (with timeout, fatal, or temporary error).

debug => $debug_level_int || 0

Debug level, 0 - print nothing, 9 - print everything

name => $name

A string used for self-description. Mainly used for debugging purposes.

Error

Last error code, or 'fail' for some network reason, oftenly a timeout.

    $box->Insert(@tuple) or die sprintf "Error %X", $box->Error; # die "Error 202"

ErrorStr

Last error code and description in a single string.

    $box->Insert(@tuple) or die $box->ErrorStr;                  # die "Error 00000202: Illegal Parameters"

Call

Call a stored procedure. Returns an arrayref of the result tuple(s) upon success.

    my $results = $box->Call('stored_procedure_name', \@procedure_params, \%options) or die $box->ErrorStr; # Call failed
    my $result_tuple = @$results && $results->[0] or warn "Call succeeded, but returned nothing";
@procedure_params

An array of bytestrings to be passed as is to the procecedure.

%options
unpack_format

Format to unpack the result tuple, the same as format option for new()

Add, Insert, Replace

    $box->Add(@tuple) or die $box->ErrorStr;         # only store a new tuple
    $box->Replace(@tuple, { space => "secondary" }); # only store an existing tuple
    $box->Insert(@tuple, { space => "main" });       # store anyway

Insert a @tuple into the storage into $options{space} or default_space space. All of them return true upon success.

All of them have the same parameters:

@tuple

A tuple to insert. All fields must be defined. All fields will be pack()ed according to format (see "new")

%options
space => $space_id_uint32_or_name_string

Specify storage space to work on.

The difference between them is the behaviour concerning tuple with the same primary key:

Select

Select tuple(s) from storage

    my $key = $id;
    my $key = [ $firstname, $lastname ];
    my @keys = ($key, ...);

    my $tuple  = $box->Select($key)              or $box->Error && die $box->ErrorStr;
    my $tuple  = $box->Select($key, \%options)   or $box->Error && die $box->ErrorStr;

    my @tuples = $box->Select(@keys)             or $box->Error && die $box->ErrorStr;
    my @tuples = $box->Select(@keys, \%options)  or $box->Error && die $box->ErrorStr;

    my $tuples = $box->Select(\@keys)            or die $box->ErrorStr;
    my $tuples = $box->Select(\@keys, \%options) or die $box->ErrorStr;
$key, @keys, \@keys

Specify keys to select. All keys must be defined.

Contextual behaviour:

  • In scalar context, you can select one $key, and the resulting tuple will be returned. Check $box->Error to see if there was an error or there is just no such key in the storage
  • In list context, you can select several @keys, and the resulting tuples will be returned. Check $box->Error to see if there was an error or there is just no such keys in the storage
  • If you select \@keys then \@tuples will be returned upon success. @tuples will be empty if there are no such keys, and false will be returned in case of error.

Other notes:

  • If you select using index on multiple fields each $key should be given as a key-tuple $key = [ $key_field1, $key_field2, ... ].
%options
space => $space_id_uint32_or_name_string

Specify storage (by id or name) space to select from.

use_index => $index_id_uint32_or_name_string

Specify index (by id or name) to use.

limit => $limit_uint32

Max tuples to select. It is set to MAX_INT32 by default.

raw => $bool

Don't hashify (see "new"), disable "utf8" processing.

hash_by => $by

Return a hashref of the resultset. If you hashify the result set, then $by must be a field name of the hash you return, otherwise it must be a number of field of the tuple. False will be returned in case of error.

Delete

Delete tuple from storage. Return false upon error.

    my $n_deleted = $box->Delete($key) or die $box->ErrorStr;
    my $n_deleted = $box->Delete($key, \%options) or die $box->ErrorStr;
    warn "Nothing was deleted" unless int $n_deleted;

    my $deleted_tuple_set = $box->Delete($key, { want_deleted_tuples => 1 }) or die $box->ErrorStr;
    warn "Nothing was deleted" unless @$deleted_tuple_set;
%options
space => $space_id_uint32_or_name_string

Specify storage space (by id or name) to work on.

want_deleted_tuple => $bool

if $bool then return deleted tuple.

UpdateMulti

Apply several update operations to a tuple.

    my @op = ([ f1 => add => 10 ], [ f1 => and => 0xFF], [ f2 => set => time() ], [ misc_string => cutend => 3 ]);

    my $n_updated = $box->UpdateMulti($key, @op) or die $box->ErrorStr;
    my $n_updated = $box->UpdateMulti($key, @op, \%options) or die $box->ErrorStr;
    warn "Nothing was updated" unless int $n_updated;

    my $updated_tuple_set = $box->UpdateMulti($key, @op, { want_result => 1 }) or die $box->ErrorStr;
    warn "Nothing was updated" unless @$updated_tuple_set;

Different fields can be updated at one shot. The same field can be updated more than once. All update operations are done atomically. Returns false upon error.

@op = ([ $field => $op => $value ], ...)
$field

Field-to-update number or name (see "fields", "LongTuple").

$op
set

Set $field to $value

add, and, xor, or

Apply an arithmetic operation to $field with argument $value Currently arithmetic operations are supported only for int32 (4-byte length) fields (and $values too)

splice, substr

Apply a perl-like splice operation to $field. $value = [$OFFSET, $LENGTH, $REPLACE_WITH]. substr is just an alias.

append, prepend

Append or prepend $field with $value string.

cutbeg, cutend

Cut $value bytes from beginning or end of $field.

%options
space => $space_id_uint32_or_name_string

Specify storage space (by id or name) to work on.

want_updated_tuple => $bool

if $bool then return updated tuple.

AnyEvent

Insert, UpdateMulti, Select, Delete, Call methods can be given the following options:

callback => sub { my ($data, $error) = @_; }

Do an async request using AnyEvent. $data contains unpacked and processed according to request options data. $error contains a message string in case of error. Set up raise => 0 to use this option.

"Continuations"

Select methods can be given the following options:

return_fh => 1

The request does only send operation on network, and returns { fh => $IO_Handle, continue => $code } or false if send operation failed. $code reads data from network, unpacks, processes according to options and returns it.

You should handle timeouts and retries manually (using select() call for example). Usage example:

    my $continuation = $box->Select(13,{ return_fh => 1 });
    ok $continuation, "select/continuation";

    my $rin = '';
    vec($rin,$continuation->{fh}->fileno,1) = 1;
    my $ein = $rin;
    ok 0 <= select($rin,undef,$ein,2), "select/continuation/select";

    my $res = $continuation->{continue}->();
    use Data::Dumper;
    is_deeply $res, [13, 'some_email@test.mail.ru', 1, 2, 3, 4, '123456789'], "select/continuation/result";

LongTuple

If format given to "new", or unpack_format given to "Call" ends with a star (*) long tuple is enabled. Last field or group of fields of format represent variable-length tail of the tuple. long_fields option given to "new" will fold the tail into array of hashes.

    $box->Insert(1,"2",3);         #1
    $box->Insert(3,"2",3,4,5);     #2
    $box->Insert(5,"2",3,4,5,6,7); #3

If we set up

    format => "L&CL*",
    fields => [qw/ a b c d /], # d is the folding field here
    # no long_fields - no folding into hash

we'll get:

    $result = $box->Select([1,2,3,4,5]);
    $result = [
        { a => 1, b => "2", c => 3, d => [] },        #1
        { a => 3, b => "2", c => 3, d => [4,5] },     #2
        { a => 5, b => "2", c => 3, d => [4,5,6,7] }, #3
    ];

And if we set up

    format => "L&C(LL)*",
    fields => [qw/ a b c d /], # d is the folding field here
    long_fields => [qw/ d1 d2 /],

we'll get:

    $result = [
        { a => 1, b => "2", c => 3, d => [] },                               #1
        { a => 3, b => "2", c => 3, d => [{d1=>4, d2=>5}] },                 #2
        { a => 5, b => "2", c => 3, d => [{d1=>4, d2=>5}, {d1=>6, d2=>7}] }, #3
    ];

"UpdateMulti" can be given a field number in several ways:

$linear_index_int
    $box->UpdateMulti(5, [ 5 => set => $val ]) #3: set 6 to $val
an arrayref of [$index_of_folded_subtuple_int, $long_field_name_str_or_index_int]
    $box->UpdateMulti(5, [ [1,0]    => set => $val ]) #3: set 6 to $val
    $box->UpdateMulti(5, [ [1,'d1'] => set => $val ]) #3: set 6 to $val

utf8

Utf8 strings are supported very simply. When pushing any data to tarantool (with any query, read or write), the utf8 flag is set off, so all data is pushed as bytestring. When reading response, for fields marked a dollar sign $ (see "new") (including such in "LongTuple" tail) utf8 flag is set on. That's all. Validity is on your own.

LICENCE AND COPYRIGHT ^

This is free software; you can redistribute it and/or modify it under the same terms as the Perl 5 programming language system itself.

SEE ALSO ^

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