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https://github.com/sile/otp_passage
OpenTracing instrumentation library for the Erlang/OTP standard modules
https://github.com/sile/otp_passage
erlang opentracing
Last synced: 2 months ago
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OpenTracing instrumentation library for the Erlang/OTP standard modules
- Host: GitHub
- URL: https://github.com/sile/otp_passage
- Owner: sile
- License: mit
- Created: 2017-10-27T20:16:18.000Z (about 7 years ago)
- Default Branch: master
- Last Pushed: 2018-12-25T14:22:03.000Z (about 6 years ago)
- Last Synced: 2024-09-16T17:46:37.760Z (3 months ago)
- Topics: erlang, opentracing
- Language: Erlang
- Homepage:
- Size: 185 KB
- Stars: 6
- Watchers: 4
- Forks: 2
- Open Issues: 0
-
Metadata Files:
- Readme: README.md
- License: LICENSE
Awesome Lists containing this project
README
otp_passage
===========
[](https://hex.pm/packages/otp_passage)
[](https://travis-ci.org/sile/otp_passage)
[](https://codecov.io/gh/sile/otp_passage/branch/master)
[](LICENSE)
[OpenTracing](http://opentracing.io/) instrumentation library for the Erlang/OTP standard modules.
This uses [passage](https://github.com/sile/passage) as OpenTracing API library.
[Documentation](https://hexdocs.pm/otp_passage/)
A Running Example
-----------------
This example uses following simple echo server.
```erlang
-module(echo_server).
-compile({parse_transform, passage_transform}). % Enables `passage_trace` attribute
-behaviour(gen_server).
-export([start_link/0, echo/1]).
-export([init/1, handle_call/3, handle_cast/2, handle_info/2, terminate/2, code_change/3]).
%% Exported Functions
start_link() ->
%% Uses `gen_server_passage` instead of `gen_server`
gen_server_passage:start_link({local, ?MODULE}, ?MODULE, [], []).
echo(Message) ->
%% Uses `gen_server_passage` instead of `gen_server`
gen_server_passage:call(?MODULE, {echo, Message}).
%% `gen_server` Callbacks
init(_) -> {ok, []}.
handle_call({echo, Message}, _, State) ->
log(Message),
{reply, Message, State}.
handle_cast(_, State) -> {noreply, State}.
handle_info(_, State) -> {noreply, State}.
terminate(_, _) -> ok.
code_change(_, State, _) -> {ok, State}.
%% Internal Functions
-passage_trace([]). % Annotation for tracing.
log(Message) ->
io:format("Received: ~p\n", [Message]),
ok.
```
By using [jaeger](https://uber.github.io/jaeger/) and [jaeger_passage](https://github.com/sile/jaeger_passage), you can easily trace and visualize the behaviour of the above server.
As the first step, you need to start jaeger daemons.
```console
$ docker run -d -p6831:6831/udp -p6832:6832/udp -p16686:16686 jaegertracing/all-in-one:latest
```
Next, start Erlang shell and execute following commands.
```erlang
% Starts `example_tracer`
> Sampler = passage_sampler_all:new().
> ok = jaeger_passage:start_tracer(example_tracer, Sampler).
% Starts `echo_server`
> {ok, _} = echo_server:start_link().
% Traces an echo request
> passage_pd:with_span(echo, [{tracer, example_tracer}],
fun () -> echo_server:echo(hello) end).
```
You can see the tracing result by your favorite browser (in this example, firefox).
```console
$ firefox http://localhost:16686/
```
