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binding.b(do: ...) hangs Rails with puma web server #248
Description
Update: it doesn't happen when used with thin server
I just noticed that binding.b(do: "") hangs the Rails on puma server. But to be more clear, it doesn't hang the request that runs the command. It stops the next one from starting.
An example:
class PostsController < ApplicationController
def index
binding.b(do: "pp 123")
@posts = Post.all
# binding.b(do: "trace off")
endStarted GET "/posts" for 127.0.0.1 at 2021-09-04 13:59:30 +0800
(0.5ms) SELECT sqlite_version(*)
(0.1ms) SELECT "schema_migrations"."version" FROM "schema_migrations" ORDER BY "schema_migrations"."version" ASC
Processing by PostsController#index as HTML
[2, 11] in ~/projects/sentry-ruby/sentry-rails/examples/rails-6.0/app/controllers/posts_controller.rb
2| before_action :set_post, only: [:show, :edit, :update, :destroy]
3|
4| # GET /posts
5| # GET /posts.json
6| def index
=> 7| binding.b(do: "pp 123")
8| @posts = Post.all
9| # binding.b(do: "trace off")
10| end
11|
=>#0 PostsController#index at ~/projects/sentry-ruby/sentry-rails/examples/rails-6.0/app/controllers/posts_controller.rb:7
#1 ActionController::BasicImplicitRender#send_action(method="index", args=[]) at ~/.rbenv/versions/2.7.2/lib/ruby/gems/2.7.0/gems/actionpack-6.0.4/lib/action_controller/metal/basic_implicit_render.rb:6
# and 73 frames (use `bt' command for all frames)
(rdbg:binding.break) pp 123
123
Rendering posts/index.html.erb within layouts/application
Post Load (0.2ms) SELECT "posts".* FROM "posts"
↳ app/views/posts/index.html.erb:15
Rendered posts/index.html.erb within layouts/application (Duration: 63.1ms | Allocations: 46972)
[Webpacker] Everything's up-to-date. Nothing to do
Completed 200 OK in 1575ms (Views: 1495.7ms | ActiveRecord: 1.6ms | Allocations: 1510204)
As you can see, it finishes the request. But when I make a second request, it seems never reach the Rails server at all (no logs).
What's worse is that the process also doesn't accept any Ctrl-c (SIGINT) exit.
However, this is not the case for binding.b or binding.b(pre: ...).
Started GET "/posts" for 127.0.0.1 at 2021-09-04 14:06:48 +0800
(0.5ms) SELECT sqlite_version(*)
(0.1ms) SELECT "schema_migrations"."version" FROM "schema_migrations" ORDER BY "schema_migrations"."version" ASC
Processing by PostsController#index as HTML
[2, 11] in ~/projects/sentry-ruby/sentry-rails/examples/rails-6.0/app/controllers/posts_controller.rb
2| before_action :set_post, only: [:show, :edit, :update, :destroy]
3|
4| # GET /posts
5| # GET /posts.json
6| def index
=> 7| binding.b(pre: "pp 123")
8| @posts = Post.all
9| # binding.b(do: "trace off")
10| end
11|
=>#0 PostsController#index at ~/projects/sentry-ruby/sentry-rails/examples/rails-6.0/app/controllers/posts_controller.rb:7
#1 ActionController::BasicImplicitRender#send_action(method="index", args=[]) at ~/.rbenv/versions/2.7.2/lib/ruby/gems/2.7.0/gems/actionpack-6.0.4/lib/action_controller/metal/basic_implicit_render.rb:6
# and 73 frames (use `bt' command for all frames)
(rdbg:binding.break) pp 123
123
(rdbg) c # continue command
Rendering posts/index.html.erb within layouts/application
Post Load (0.2ms) SELECT "posts".* FROM "posts"
↳ app/views/posts/index.html.erb:15
Rendered posts/index.html.erb within layouts/application (Duration: 26.0ms | Allocations: 49588)
[Webpacker] Everything's up-to-date. Nothing to do
Completed 200 OK in 3522ms (Views: 1039.9ms | ActiveRecord: 0.7ms | Allocations: 1543430)
Started GET "/posts" for 127.0.0.1 at 2021-09-04 14:06:52 +0800
Processing by PostsController#index as HTML
[2, 11] in ~/projects/sentry-ruby/sentry-rails/examples/rails-6.0/app/controllers/posts_controller.rb
2| before_action :set_post, only: [:show, :edit, :update, :destroy]
3|
4| # GET /posts
5| # GET /posts.json
6| def index
=> 7| binding.b(pre: "pp 123")
8| @posts = Post.all
9| # binding.b(do: "trace off")
10| end
11|
=>#0 PostsController#index at ~/projects/sentry-ruby/sentry-rails/examples/rails-6.0/app/controllers/posts_controller.rb:7
#1 ActionController::BasicImplicitRender#send_action(method="index", args=[]) at ~/.rbenv/versions/2.7.2/lib/ruby/gems/2.7.0/gems/actionpack-6.0.4/lib/action_controller/metal/basic_implicit_render.rb:6
# and 73 frames (use `bt' command for all frames)
(rdbg:binding.break) pp 123
123
(rdbg) c # continue command
Rendering posts/index.html.erb within layouts/application
Post Load (0.1ms) SELECT "posts".* FROM "posts"
↳ app/views/posts/index.html.erb:15
Rendered posts/index.html.erb within layouts/application (Duration: 2.0ms | Allocations: 1513)
[Webpacker] Everything's up-to-date. Nothing to do
Completed 200 OK in 1120ms (Views: 16.9ms | ActiveRecord: 0.1ms | Allocations: 61312)
So I suspect it has something to do with the present commands' auto continue mechanism.
Activity
[-]binding.b(do: ...) hangs Rails server[/-][+]binding.b(do: ...) hangs Rails with puma web server[/+]st0012 commentedon Sep 4, 2021
This may be related: calling
binding.b(do: ..)in threads seems to cause lock.But not
binding.b(pre: ...)ko1 commentedon Sep 6, 2021
could you try it? the issue of simple thread example was solved with this patch.
ko1 commentedon Sep 6, 2021
ah, I missed your PR.