├── .gitignore ├── LICENSE ├── README.md ├── rebar.config ├── rebar.lock └── src ├── tracelog.app.src └── tracelog.erl /.gitignore: -------------------------------------------------------------------------------- 1 | .rebar3 2 | _* 3 | .eunit 4 | *.o 5 | *.beam 6 | *.plt 7 | *.swp 8 | *.swo 9 | .erlang.cookie 10 | ebin 11 | log 12 | erl_crash.dump 13 | .rebar 14 | logs 15 | _build 16 | .idea 17 | *.iml 18 | rebar3.crashdump 19 | *~ 20 | -------------------------------------------------------------------------------- /LICENSE: -------------------------------------------------------------------------------- 1 | Apache License 2 | Version 2.0, January 2004 3 | http://www.apache.org/licenses/ 4 | 5 | TERMS AND CONDITIONS FOR USE, REPRODUCTION, AND DISTRIBUTION 6 | 7 | 1. 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In no event and under no legal theory, 154 | whether in tort (including negligence), contract, or otherwise, 155 | unless required by applicable law (such as deliberate and grossly 156 | negligent acts) or agreed to in writing, shall any Contributor be 157 | liable to You for damages, including any direct, indirect, special, 158 | incidental, or consequential damages of any character arising as a 159 | result of this License or out of the use or inability to use the 160 | Work (including but not limited to damages for loss of goodwill, 161 | work stoppage, computer failure or malfunction, or any and all 162 | other commercial damages or losses), even if such Contributor 163 | has been advised of the possibility of such damages. 164 | 165 | 9. Accepting Warranty or Additional Liability. While redistributing 166 | the Work or Derivative Works thereof, You may choose to offer, 167 | and charge a fee for, acceptance of support, warranty, indemnity, 168 | or other liability obligations and/or rights consistent with this 169 | License. However, in accepting such obligations, You may act only 170 | on Your own behalf and on Your sole responsibility, not on behalf 171 | of any other Contributor, and only if You agree to indemnify, 172 | defend, and hold each Contributor harmless for any liability 173 | incurred by, or claims asserted against, such Contributor by reason 174 | of your accepting any such warranty or additional liability. 175 | 176 | END OF TERMS AND CONDITIONS 177 | 178 | Copyright 2018, Fred Hebert . 179 | 180 | Licensed under the Apache License, Version 2.0 (the "License"); 181 | you may not use this file except in compliance with the License. 182 | You may obtain a copy of the License at 183 | 184 | http://www.apache.org/licenses/LICENSE-2.0 185 | 186 | Unless required by applicable law or agreed to in writing, software 187 | distributed under the License is distributed on an "AS IS" BASIS, 188 | WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 189 | See the License for the specific language governing permissions and 190 | limitations under the License. 191 | 192 | -------------------------------------------------------------------------------- /README.md: -------------------------------------------------------------------------------- 1 | tracelog 2 | ===== 3 | 4 | A logging handler that can transforms structured logs into opencensus distributed tracing spans 5 | 6 | Configuration 7 | ------------- 8 | 9 | This library only works with logs that can be paired up with one that 'starts' and one that 'stops' a given event. For example, the following configuration: 10 | 11 | ```erlang 12 | [ 13 | {kernel, [ 14 | {logger, [ 15 | {handler, opencensus, tracelog, 16 | #{open_close_pairs => [ 17 | % {key name, {open val, close val}} 18 | {type, {command, event}}, 19 | {part, {request, response}}, 20 | {trace, {start, stop}} 21 | ], 22 | name_keys => [what, span] 23 | } 24 | } 25 | ]}, 26 | {logger_level, info} 27 | ]}, 28 | ... 29 | ]. 30 | ``` 31 | 32 | This means that any log that has any of the keys/values below will work: 33 | 34 | ```erlang 35 | %% any log level works 36 | ?LOG_INFO(#{... type => command, ...}) % opens the span 37 | ?LOG_INFO(#{... type => event, ...}) % closes the span 38 | 39 | ?LOG_INFO(#{... part => request, ...}) % opens the span 40 | ?LOG_INFO(#{... part => response, ...}) % closes the span 41 | 42 | ?LOG_INFO(#{... trace => start, ...}) % opens the span 43 | ?LOG_INFO(#{... trace => stop, ...}) % closes the span 44 | ``` 45 | 46 | By default, only `{trace, {start, stop}}` is configured. The list of trace types given is scanned in order, so the most frequently expected keys should be put first. 47 | 48 | The name of the span will be defined by any of the `name_keys` arguments, in the precedence given by the list. If no matching label fits, the handler defaults to using the calling function name defined by the `mfa` meta value inserted by the `logger` library. If no such label nor `mfa` value is available, the name `undefined` is used by the span. 49 | 50 | Notes 51 | ----- 52 | 53 | This log handler does not output any log lines, it only forwards calls to opencensus. You still have to carry the opencensus trace context across processes of services yourself; this handler only makes it easier to reuse logs as spans to provide detailed tracing views. 54 | -------------------------------------------------------------------------------- /rebar.config: -------------------------------------------------------------------------------- 1 | {erl_opts, [debug_info]}. 2 | {deps, [opencensus]}. 3 | -------------------------------------------------------------------------------- /rebar.lock: -------------------------------------------------------------------------------- 1 | {"1.1.0", 2 | [{<<"counters">>,{pkg,<<"counters">>,<<"0.2.1">>},1}, 3 | {<<"ctx">>,{pkg,<<"ctx">>,<<"0.5.0">>},1}, 4 | {<<"jsx">>,{pkg,<<"jsx">>,<<"2.9.0">>},1}, 5 | {<<"opencensus">>,{pkg,<<"opencensus">>,<<"0.7.0">>},0}, 6 | {<<"rfc3339">>,{pkg,<<"rfc3339">>,<<"0.9.0">>},2}, 7 | {<<"wts">>,{pkg,<<"wts">>,<<"0.3.0">>},1}]}. 8 | [ 9 | {pkg_hash,[ 10 | {<<"counters">>, <<"AA3D97E88F92573488987193D0F48EFCE0F3B2CD1443BF4EE760BC7F99322F0C">>}, 11 | {<<"ctx">>, <<"78E0F16712E12D707A7F34277381B8E193D7C71EAA24D37330DC02477C09EDA5">>}, 12 | {<<"jsx">>, <<"D2F6E5F069C00266CAD52FB15D87C428579EA4D7D73A33669E12679E203329DD">>}, 13 | {<<"opencensus">>, <<"B4C5F6A96F2BA2154570F24BB08B65D6EE0FF5B61518ACF706CA760B7696A4E1">>}, 14 | {<<"rfc3339">>, <<"2075653DC9407541C84B1E15F8BDA2ABE95FB17C9694025E079583F2D19C1060">>}, 15 | {<<"wts">>, <<"5CDF22C775CB1EBAE24C326A5DB6074D753C42F4BD12A9AA47CC62D3E2C71AD1">>}]} 16 | ]. 17 | -------------------------------------------------------------------------------- /src/tracelog.app.src: -------------------------------------------------------------------------------- 1 | {application, tracelog, 2 | [{description, "A log handler for structured logs that plays with opencensus"}, 3 | {vsn, "0.1.0"}, 4 | {registered, []}, 5 | {applications, 6 | [kernel, 7 | stdlib, 8 | opencensus 9 | ]}, 10 | {env,[]}, 11 | {modules, []}, 12 | 13 | {maintainers, ["Fred Hebert"]}, 14 | {licenses, ["Apache 2.0"]}, 15 | {links, []} 16 | ]}. 17 | -------------------------------------------------------------------------------- /src/tracelog.erl: -------------------------------------------------------------------------------- 1 | -module(tracelog). 2 | -export([adding_handler/1, removing_handler/1, log/2]). 3 | 4 | adding_handler(Config = #{}) -> 5 | PKList = maps:get(open_close_pairs, Config, [{trace, {start, stop}}]), 6 | Cfg = #{ 7 | pair_keys => [K || {K, _} <- PKList], % preserve user-supplied order 8 | pairs => maps:from_list(PKList), 9 | name_keys => maps:get(name_keys, Config, [name]) 10 | }, 11 | NewConfig = maps:without( 12 | [open_close_pairs, name_keys], 13 | Config 14 | ), 15 | {ok, NewConfig#{config => Cfg}}. 16 | 17 | removing_handler(_Config) -> 18 | ok. 19 | 20 | log(#{meta := Meta, msg := {report, Msg}}, 21 | #{config := #{pair_keys := Ks, pairs := Ps, name_keys := Ns}}) -> 22 | case matching_keywords(Ks, Ps, Msg) of 23 | {K, {Start, Stop}} -> 24 | case Msg of 25 | #{K := Start} -> 26 | Span = span_name(Ns, Msg, Meta), 27 | put({?MODULE, command, Span}, {seen, Stop}), 28 | ocp:with_child_span(Span); 29 | #{K := End} -> 30 | Span = span_name(Ns, Msg, Meta), 31 | case get({?MODULE, command, Span}) of 32 | undefined -> 33 | ignore; 34 | {seen, End} -> 35 | erase({?MODULE, command, Span}), 36 | ocp:finish_span() 37 | end; 38 | _ -> 39 | ok 40 | end; 41 | undefined -> 42 | ok 43 | end; 44 | log(_, _) -> 45 | ignore. 46 | 47 | matching_keywords([], _, _) -> 48 | undefined; 49 | matching_keywords([H|T], Pairs, Msg) -> 50 | case Msg of 51 | #{H := _} -> 52 | {H, maps:get(H, Pairs)}; 53 | _ -> 54 | matching_keywords(T, Pairs, Msg) 55 | end. 56 | 57 | span_name([], _, #{mfa := MFA}) -> to_bin(MFA); 58 | span_name([], _, _) -> <<"undefined">>; 59 | span_name([H|T], Msg, Meta) -> 60 | case Msg of 61 | #{H := V} -> to_bin(V); 62 | _ -> span_name(T, Msg, Meta) 63 | end. 64 | 65 | to_bin({M,F,A0}) -> 66 | A = if is_integer(A0) -> A0; 67 | is_list(A0) -> length(A0) 68 | end, 69 | <<(atom_to_binary(M, utf8))/binary, ":", 70 | (atom_to_binary(F, utf8))/binary, "/", 71 | (integer_to_binary(A))/binary>>; 72 | to_bin(Str) when is_list(Str) -> 73 | unicode:characters_to_binary(Str); 74 | to_bin(Atom) when is_atom(Atom) -> 75 | atom_to_binary(Atom, utf8). 76 | --------------------------------------------------------------------------------