Skip to content

fix(opentelemetry_cowboy): prevent telemetry handler crash on invalid HTTP/2 scheme #568

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Open
velimir wants to merge 2 commits into
base: main
Choose a base branch
from
Open

fix(opentelemetry_cowboy): prevent telemetry handler crash on invalid HTTP/2 scheme #568

Show file tree
Hide file tree
Changes from all commits
Commits
Show all changes
2 commits
Select commit Hold shift + click to select a range
9865d06
upgrade opentelemetry_api to 1.5.0
velimir Dec 3, 2025
71cca4b
fix(opentelemetry_cowboy): prevent telemetry handler crash on invalid…
velimir Dec 3, 2025
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
6 changes: 3 additions & 3 deletions instrumentation/opentelemetry_cowboy/rebar.lock
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -2,7 +2,7 @@
[{<<"cowboy">>,{pkg,<<"cowboy">>,<<"2.12.0">>},1},
{<<"cowboy_telemetry">>,{pkg,<<"cowboy_telemetry">>,<<"0.4.0">>},0},
{<<"cowlib">>,{pkg,<<"cowlib">>,<<"2.13.0">>},2},
{<<"opentelemetry_api">>,{pkg,<<"opentelemetry_api">>,<<"1.4.0">>},0},
{<<"opentelemetry_api">>,{pkg,<<"opentelemetry_api">>,<<"1.5.0">>},0},
{<<"opentelemetry_semantic_conventions">>,
{pkg,<<"opentelemetry_semantic_conventions">>,<<"1.27.0">>},
0},
Expand All @@ -17,7 +17,7 @@
{<<"cowboy">>, <<"F276D521A1FF88B2B9B4C54D0E753DA6C66DD7BE6C9FCA3D9418B561828A3731">>},
{<<"cowboy_telemetry">>, <<"F239F68B588EFA7707ABCE16A84D0D2ACF3A0F50571F8BB7F56A15865AAE820C">>},
{<<"cowlib">>, <<"DB8F7505D8332D98EF50A3EF34B34C1AFDDEC7506E4EE4DD4A3A266285D282CA">>},
{<<"opentelemetry_api">>, <<"63CA1742F92F00059298F478048DFB826F4B20D49534493D6919A0DB39B6DB04">>},
{<<"opentelemetry_api">>, <<"1A676F3E3340CAB81C763E939A42E11A70C22863F645AA06AAFEFC689B5550CF">>},
{<<"opentelemetry_semantic_conventions">>, <<"ACD0194A94A1E57D63DA982EE9F4A9F88834AE0B31B0BD850815FE9BE4BBB45F">>},
{<<"opentelemetry_telemetry">>, <<"410AB4D76B0921F42DBCCBE5A7C831B8125282850BE649EE1F70050D3961118A">>},
{<<"otel_http">>, <<"B17385986C7F1B862F5D577F72614ECAA29DE40392B7618869999326B9A61D8A">>},
Expand All @@ -27,7 +27,7 @@
{<<"cowboy">>, <<"8A7ABE6D183372CEB21CAA2709BEC928AB2B72E18A3911AA1771639BEF82651E">>},
{<<"cowboy_telemetry">>, <<"7D98BAC1EE4565D31B62D59F8823DFD8356A169E7FCBB83831B8A5397404C9DE">>},
{<<"cowlib">>, <<"E1E1284DC3FC030A64B1AD0D8382AE7E99DA46C3246B815318A4B848873800A4">>},
{<<"opentelemetry_api">>, <<"3DFBBFAA2C2ED3121C5C483162836C4F9027DEF469C41578AF5EF32589FCFC58">>},
{<<"opentelemetry_api">>, <<"F53EC8A1337AE4A487D43AC89DA4BD3A3C99DDF576655D071DEED8B56A2D5DDA">>},
{<<"opentelemetry_semantic_conventions">>, <<"9681CCAA24FD3D810B4461581717661FD85FF7019B082C2DFF89C7D5B1FC2864">>},
{<<"opentelemetry_telemetry">>, <<"641AB469DEB181957AC6D59BCE6E1321D5FE2A56DF444FC9C19AFCAD623AB253">>},
{<<"otel_http">>, <<"F2BEADF922C8CFEB0965488DD736C95CC6EA8B9EFCE89466B3904D317D7CC717">>},
Expand Down
14 changes: 6 additions & 8 deletions instrumentation/opentelemetry_cowboy/src/opentelemetry_cowboy.erl
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -95,7 +95,8 @@ default_opts() ->
scheme_headers => [<<"forwarded">>, <<"x-forwarded-proto">>],
scheme_headers_sort_fn => undefined,
server_address_headers => [<<"forwarded">>, <<"x-forwarded-host">>, <<"host">>],
server_address_headers_sort_fn => undefined
server_address_headers_sort_fn => undefined,
valid_schemes => #{<<"http">> => http, <<"https">> => https}
}.

?DOC("""
Expand All @@ -114,6 +115,7 @@ Supported options:
* `scheme_headers_sort_fn` - Custom scheme header sort fn. See `otel_http` for more info. Default: `undefined`
* `server_address_headers` - Headers to use for extracting original server address info. Default: `[<<"forwarded">>, <<"x-forwarded-host">>, <<"host">>]`
* `server_address_headers_sort_fn` - Custom server header sort fn. See `otel_http` for more info. Default: `undefined`
* `valid_schemes` - Map of valid scheme binaries to atoms. Unknown schemes return `undefined`. Default: `#{<<"http">> => http, <<"https">> => https}`
""").
-spec setup() -> ok.
setup() ->
Expand Down Expand Up @@ -227,7 +229,8 @@ otel_http_extract_scheme(Headers, SortFn) ->
extract_scheme(Req, Config) ->
#{
scheme_headers := SchemeHeaders,
scheme_headers_sort_fn := SortFn
scheme_headers_sort_fn := SortFn,
valid_schemes := ValidSchemes
} = Config,
#{
headers := Headers,
Expand All @@ -236,12 +239,7 @@ extract_scheme(Req, Config) ->
SchemeHeaders1 = extract_headers(Headers, SchemeHeaders),
case otel_http_extract_scheme(SchemeHeaders1, SortFn) of
undefined ->
case ReqScheme of
<<"http">> ->
http;
<<"https">> ->
https
end;
maps:get(ReqScheme, ValidSchemes, undefined);
ParsedScheme ->
ParsedScheme
end.
Expand Down
20 changes: 19 additions & 1 deletion instrumentation/opentelemetry_cowboy/test/opentelemetry_cowboy_SUITE.erl
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -31,7 +31,8 @@ all() ->
idle_timeout_request,
chunk_timeout_request,
bad_request,
binary_status_code_request
binary_status_code_request,
invalid_scheme_returns_undefined
].

init_per_suite(Config) ->
Expand Down Expand Up @@ -507,3 +508,20 @@ binary_status_code_request(_Config) ->
after
1000 -> ct:fail(binary_status_code_request)
end.

invalid_scheme_returns_undefined(_Config) ->
Opts = #{
valid_schemes => #{<<"https">> => https}
},
opentelemetry_cowboy:setup(Opts),
Port = 62662,
{ok, {{_Version, 200, _ReasonPhrase}, _Headers, _Body}} =
httpc:request(get, {"http://localhost:8080/success", []}, [], [{socket_opts, [{port, Port}]}]),
receive
{span, #span{name=Name,attributes=Attributes,kind=Kind}} ->
?assertEqual('GET', Name),
?assertEqual(?SPAN_KIND_SERVER, Kind),
?assertEqual(undefined, maps:get(?URL_SCHEME, otel_attributes:map(Attributes)))
after
1000 -> ct:fail(invalid_scheme_returns_undefined)
end.
Comment on lines +512 to +527
Copy link

Copilot AI Dec 3, 2025

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

The test configures valid_schemes to only accept https, then makes an http:// request. While this correctly tests the scenario of an invalid scheme returning undefined, the test doesn't verify that the handler doesn't crash, which was the original bug being fixed. Consider adding a second request after the first to ensure the telemetry handler is still attached and functioning after encountering an invalid scheme.

Copilot uses AI. Check for mistakes.
Copy link
Author

@velimir velimir Dec 3, 2025

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

I would love to, but making an http2 request via httpc is.. problematic.