Opentelemetry instrumentation http (#186)

* Add opentelemetry_instrumentation_http utility library

* Update utilities/opentelemetry_instrumentation_http/src/opentelemetry_instrumentation_http.erl

Co-authored-by: Tristan Sloughter <t@crashfast.com>

* Fix dialyzer

* Update changelog

---------

Co-authored-by: Tristan Sloughter <t@crashfast.com>

.github/labeler.yml

@@ -82,3 +82,6 @@ opentelemetry_tesla:
 
 opentelemetry_xray:
   - utilities/opentelemetry_xray/**/*
+
+opentelemetry_instrumentation_http:
+  - utilities/opentelemetry_instrumentation_http/**/*

.github/workflows/erlang.yml

@@ -118,3 +118,34 @@ jobs:
         run: rebar3 get-deps
       - name: Test
         run: rebar3 ct
+
+  opentelemetry-instrumentation-http:
+    needs: [test-matrix]
+    if: (contains(github.event.pull_request.labels.*.name, 'erlang') && contains(github.event.pull_request.labels.*.name, 'opentelemetry_instrumentation_http'))
+    env:
+      app: "opentelemetry_instrumentation_http"
+    defaults:
+      run:
+        working-directory: utilities/${{ env.app }}
+    runs-on: ubuntu-20.04
+    name: OpenTelemetry Instrumentation HTTP test on OTP ${{ matrix.otp_version }} with Rebar3 ${{ matrix.rebar3_version }}
+    strategy:
+      fail-fast: false
+      matrix: ${{ fromJson(needs.test-matrix.outputs.matrix) }}
+    steps:
+      - uses: actions/checkout@v3
+      - uses: erlef/setup-beam@v1
+        with:
+          otp-version: ${{ matrix.otp_version }}
+          rebar3-version: ${{ matrix.rebar3_version }}
+      - name: Cache
+        uses: actions/cache@v3
+        with:
+          path: |
+            ~/_build
+          key: ${{ runner.os }}-build-${{ matrix.otp_version }}-${{ matrix.rebar3_version }}-v3-${{ hashFiles('**/rebar.lock') }}
+      - name: Fetch deps
+        if: steps.deps-cache.outputs.cache-hit != 'true'
+        run: rebar3 get-deps
+      - name: Test
+        run: rebar3 eunit

utilities/opentelemetry_instrumentation_http/.gitignore

@@ -0,0 +1,19 @@
+.rebar3
+_*
+.eunit
+*.o
+*.beam
+*.plt
+*.swp
+*.swo
+.erlang.cookie
+ebin
+log
+erl_crash.dump
+.rebar
+logs
+_build
+.idea
+*.iml
+rebar3.crashdump
+*~

utilities/opentelemetry_instrumentation_http/CHANGELOG.md

@@ -0,0 +1,7 @@
+# Changelog
+
+## v0.1.0
+
+### Changed
+
+* Expose `extract_headers_attributes/3` and `normalize_header_name/1` fucntions to extracted selected headers in an attribute map following semantic conventions

utilities/opentelemetry_instrumentation_http/LICENSE

@@ -0,0 +1,191 @@
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+

utilities/opentelemetry_instrumentation_http/README.md

@@ -0,0 +1,22 @@
+# opentelemetry_instrumentation_http
+
+[![EEF Observability WG project](https://img.shields.io/badge/EEF-Observability-black)](https://github.com/erlef/eef-observability-wg)
+[![Hex.pm](https://img.shields.io/hexpm/v/opentelemetry_instrumentation_http)](https://hex.pm/packages/opentelemetry_instrumentation_http)
+![Build Status](https://github.com/open-telemetry/opentelemetry-erlang-contrib/workflows/Erlang/badge.svg)
+
+
+## Installation
+
+```erlang
+{deps, [
+  {opentelemetry_instrumentation_http, "~> 0.1"}
+]}
+```
+```elixir
+def deps do
+  [
+    {:opentelemetry_instrumentation_http, "~> 0.1"}
+  ]
+end
+```
+

utilities/opentelemetry_instrumentation_http/docs.config

@@ -0,0 +1,4 @@
+{source_url, <<"https://github.com/open-telemetry/opentelemetry-erlang-contrib/tree/main/utilities/opentelemetry_instrumentation_http">>}.
+{extras, [<<"LICENSE">>]}.
+{main, <<"opentelemetry_instrumentation_http">>}.
+{proglang, erlang}.

utilities/opentelemetry_instrumentation_http/docs.sh

@@ -0,0 +1,15 @@
+#!/bin/bash
+set -e
+
+# Setup:
+#
+#     mix escript.install github elixir-lang/ex_doc
+#     asdf install erlang 24.0.2
+#     asdf local erlang 24.0.2
+
+rebar3 compile
+rebar3 as docs edoc
+version=0.1.0
+ex_doc "opentelemetry_instrumentation_http" $version "_build/default/lib/opentelemetry_instrumentation_http/ebin" \
+       --source-ref v${version} \
+       --config docs.config $@

utilities/opentelemetry_instrumentation_http/rebar.config

@@ -0,0 +1,37 @@
+{erl_opts, [debug_info]}.
+{deps, []}.
+
+{project_plugins, [
+    covertool,
+    erlfmt,
+    rebar3_hex
+]}.
+{profiles, [
+    {docs, [
+        {deps, [edown]},
+        {edoc_opts, [
+            {preprocess, true},
+            {doclet, edoc_doclet_chunks},
+            {layout, edoc_layout_chunks},
+            {dir, "_build/default/lib/opentelemetry_instrumentation_http/doc"},
+            {subpackages, true}
+        ]}
+    ]},
+    {test, [
+        {erl_opts, [nowarn_export_all]},
+        {deps, []},
+        {ct_opts, [{ct_hooks, [cth_surefire]}]}
+    ]}
+]}.
+
+{xref_checks, [
+    undefined_function_calls,
+    undefined_functions,
+    deprecated_function_calls,
+    deprecated_functions
+]}.
+{xref_ignores, []}.
+
+{cover_enabled, true}.
+{cover_export_enabled, true}.
+{covertool, [{coverdata_files, ["ct.coverdata"]}]}.

utilities/opentelemetry_instrumentation_http/rebar.lock

@@ -0,0 +1 @@
+[].

utilities/opentelemetry_instrumentation_http/src/opentelemetry_instrumentation_http.app.src

@@ -0,0 +1,17 @@
+{application, opentelemetry_instrumentation_http, [
+    {description, "OpenTelemetry Instrumentation utilities for HTTP libraries"},
+    {vsn, "0.1.0"},
+    {registered, []},
+    {applications, [
+        kernel,
+        stdlib
+    ]},
+    {env, []},
+    {modules, []},
+    {doc, "doc"},
+    {licenses, ["Apache 2.0"]},
+    {links, [
+        {"GitHub",
+            "https://github.com/open-telemetry/opentelemetry-erlang-contrib/tree/main/utilities/opentelemetry_instrumentation_http"}
+    ]}
+]}.

utilities/opentelemetry_instrumentation_http/src/opentelemetry_instrumentation_http.erl

@@ -0,0 +1,110 @@
+-module(opentelemetry_instrumentation_http).
+
+-ifdef(TEST).
+-include_lib("eunit/include/eunit.hrl").
+-endif.
+
+-export([
+    extract_headers_attributes/3,
+    normalize_header_name/1
+]).
+
+-spec normalize_header_name(string() | binary()) -> Result when
+      Result :: binary() | {error, binary(), RestData} | {incomplete, binary(), binary()},
+      RestData :: unicode:latin1_chardata() | unicode:chardata() | unicode:external_chardata().
+normalize_header_name(Header) when is_binary(Header) ->
+    normalize_header_name(binary_to_list(Header));
+normalize_header_name(Header) when is_list(Header) ->
+    unicode:characters_to_binary(string:replace(string:to_lower(Header), "-", "_", all)).
+
+-spec extract_headers_attributes(
+    request | response,
+    Headers ::
+        #{binary() | string() => binary() | [binary()]}
+        | [{binary() | string(), binary() | [binary()]}],
+    HeadersToExtract :: [binary()]
+) -> #{atom() => [binary()]}.
+extract_headers_attributes(_Context, _Headers, []) ->
+    #{};
+extract_headers_attributes(Context, Headers, HeadersToExtract) when is_list(Headers) ->
+    lists:foldr(
+        fun({HeaderName, HeaderValue}, Extracted) ->
+            extract_if_match(Context, HeaderName, HeaderValue, Extracted, HeadersToExtract)
+        end,
+        #{},
+        Headers
+    );
+extract_headers_attributes(Context, Headers, HeadersToExtract) when is_map(Headers) ->
+    maps:fold(
+        fun(HeaderName, HeaderValue, Extracted) ->
+            extract_if_match(Context, HeaderName, HeaderValue, Extracted, HeadersToExtract)
+        end,
+        #{},
+        Headers
+    ).
+
+extract_if_match(Context, HeaderName, HeaderValue, Extracted, HeadersToExtract) ->
+    NormalizedHeaderName = normalize_header_name(HeaderName),
+    case lists:member(NormalizedHeaderName, HeadersToExtract) of
+        false -> Extracted;
+        true -> set_header_attribute(Context, NormalizedHeaderName, HeaderValue, Extracted)
+    end.
+
+set_header_attribute(Context, Header, Value, HeadersAttributes) when is_list(Value) ->
+    maps:put(attribute_name(Context, Header), Value, HeadersAttributes);
+set_header_attribute(Context, Header, Value, HeadersAttributes) ->
+    maps:update_with(
+        attribute_name(Context, Header), fun(V) -> [Value | V] end, [Value], HeadersAttributes
+    ).
+
+attribute_name(request, HeaderName) ->
+    binary_to_atom(<<"http.request.header.", HeaderName/binary>>);
+attribute_name(response, HeaderName) ->
+    binary_to_atom(<<"http.response.header.", HeaderName/binary>>).
+
+-ifdef(TEST).
+
+normalize_header_name_test_() ->
+    [
+        ?_assertEqual(normalize_header_name(<<"Content-Type">>), <<"content_type">>),
+        ?_assertEqual(normalize_header_name("Some-Header-NAME"), <<"some_header_name">>)
+    ].
+
+extract_headers_attributes_test_() ->
+    [
+        ?_assertEqual(extract_headers_attributes(request, [], []), #{}),
+        ?_assertEqual(extract_headers_attributes(response, #{}, []), #{}),
+        ?_assertEqual(
+            extract_headers_attributes(
+                request,
+                #{
+                    <<"Foo">> => <<"1">>,
+                    "Bar-Baz" => [<<"2">>, <<"3">>],
+                    "To-Not-Extract" => <<"4">>
+                },
+                [<<"foo">>, <<"bar_baz">>]
+            ),
+            #{
+                'http.request.header.foo' => [<<"1">>],
+                'http.request.header.bar_baz' => [<<"2">>, <<"3">>]
+            }
+        ),
+        ?_assertEqual(
+            extract_headers_attributes(
+                response,
+                [
+                    {<<"Foo">>, <<"1">>},
+                    {"Bar-Baz", <<"2">>},
+                    {"To-Not-Extract", <<"3">>},
+                    {<<"foo">>, <<"4">>}
+                ],
+                [<<"foo">>, <<"bar_baz">>]
+            ),
+            #{
+                'http.response.header.foo' => [<<"1">>, <<"4">>],
+                'http.response.header.bar_baz' => [<<"2">>]
+            }
+        )
+    ].
+
+-endif.