# frozen_string_literal: true
module Gitlab
module Middleware
class Speedscope
def initialize(app)
@app = app
end
def call(env)
request = ActionDispatch::Request.new(env)
return @app.call(env) unless rendering_flamegraph?(request)
body = nil
::Gitlab::SafeRequestStore[:capturing_flamegraph] = true
require 'stackprof'
begin
mode = stackprof_mode(request)
flamegraph = ::StackProf.run(
mode: mode,
raw: true,
aggregate: false,
interval: ::Gitlab::StackProf.interval(mode)
) do
_, _, body = @app.call(env)
end
ensure
body.close if body.respond_to?(:close)
end
render_flamegraph(flamegraph, request)
end
private
def rendering_flamegraph?(request)
request.params['performance_bar'] == 'flamegraph' && ::Gitlab::PerformanceBar.allowed_for_user?(request.env['warden']&.user)
end
def render_flamegraph(graph, request)
headers = { 'Content-Type' => 'text/html' }
path = request.env['PATH_INFO'].sub('//', '/')
speedscope_path = ::Gitlab::Utils.append_path(::Gitlab.config.gitlab.relative_url_root, '/-/speedscope/index.html')
html = <<~HTML
<!DOCTYPE html>
<html>
<head>
<style>
body { margin: 0; height: 100vh; }
#speedscope-iframe { width: 100%; height: 100%; border: none; }
</style>
</head>
<body>
<script type="text/javascript" nonce="#{request.content_security_policy_nonce}">
var graph = #{Gitlab::Json.generate(graph)};
var json = JSON.stringify(graph);
var blob = new Blob([json], { type: 'text/plain' });
var objUrl = encodeURIComponent(URL.createObjectURL(blob));
var iframe = document.createElement('IFRAME');
iframe.setAttribute('id', 'speedscope-iframe');
document.body.appendChild(iframe);
var iframeUrl = '#{speedscope_path}#profileURL=' + objUrl + '&title=' + 'Flamegraph for #{CGI.escape(path)} in #{stackprof_mode(request)} mode';
iframe.setAttribute('src', iframeUrl);
</script>
</body>
</html>
HTML
[200, headers, [html]]
end
def stackprof_mode(request)
case request.params['stackprof_mode']&.to_sym
when :cpu
:cpu
when :object
:object
else
:wall
end
end
end
end
end