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dp_decoder

0.2.5
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Collection of decoders for different metric protocols

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dp_decoder src dp_decoder.erl
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src/dp_decoder.erl 

-module(dp_decoder).



-ifdef(TEST).

-include_lib("eunit/include/eunit.hrl").

-endif.



-export([recombine_tags/1, to_number/1, protocol/1, parse/2]).

-export_type([metric/0, protocol/0]).



-type metric() :: #{

              metric => [binary()],

              key => [binary()],

              tags => [{binary(), binary(), binary()}],

              time => pos_integer(),

              value => integer()

             }.



-type protocol() :: dp_line_proto.



-callback parse(In::binary()) ->

    {ok, [dp_decoder:metric()]} | {error, term()} | undefined.



-callback protocol() ->

    dp_decoder:protocol().



recombine_tags(Tags) ->

    [<<K/binary, "=", V/binary>> || {_,K,V} <- Tags].



to_number(X) ->

    try

        binary_to_float(fix_num(X, <<>>))

    catch

        error:badarg ->

            binary_to_integer(X)

    end.



-spec parse(Decoder::module(), In::binary()) ->

                   {ok, [dp_decoder:metric()]} | {error, term()} | undefined.

parse(Decoder, In) ->

    Decoder:parse(In).



-spec protocol(Decoder :: module()) ->

    dp_decoder:protocol().

protocol(Decoder) ->

    Decoder:protocol().



fix_num(<<>>, Acc) ->

    Acc;

fix_num(<<"e", R/binary>>, Acc) ->

    <<Acc/binary, ".0e", R/binary>>;

fix_num(<<".", R/binary>>, Acc) ->

    <<Acc/binary, ".", R/binary>>;

fix_num(<<C, R/binary>>, Acc) ->

    fix_num(R, <<Acc/binary, C>>).





-ifdef(TEST).

to_number_test_() ->

    [?_assertEqual(to_number(<<"21.12">>), 21.12),

     ?_assertEqual(to_number(<<"21">>), 21),

     ?_assertEqual(to_number(<<"1.2e-2">>), 0.012),

     ?_assertEqual(to_number(<<"12e-2">>), 0.12)].

-endif.