support services run with multiple threads

[iuhilnehc-ynos]

Fixes #314 Signed-off-by: Chen Lihui [email protected]

[iuhilnehc-ynos]

This patch is to:

• make ros2 client call ros1 service via ros1_bridge at the same time if ros1 service is supported with multiple threads (Multi-threaded Spinning).

https://github.com/iuhilnehc-ynos/ros_tutorials/blob/44666088677028f4edeb6246b9f791c489dbb653/roscpp_tutorials/add_two_ints_server/add_two_ints_server.cpp#L57-L59

running ros2 run examples_rclcpp_minimal_client client_main& ros2 run examples_rclcpp_minimal_client client_main to expect this service can serve multiple requests at the same time.

[ INFO] [1621936604.891178820]: request: x=41, y=1
[ INFO] [1621936604.891784270]:   sending back response: [42]
[ INFO] [1621936604.892629346]: request: x=41, y=1
[ INFO] [1621936604.892643574]:   sending back response: [42]
              ^^^^^^^^^//\   the timestamp of two requests are almost same.

without this patch, the log as following,

[ INFO] [1621933196.546494184]: request: x=41, y=1
[ INFO] [1621933196.546513489]:   sending back response: [42]
[ INFO] [1621933198.556169433]: request: x=41, y=1
              ^^^^^^^^^^^^^^^^^^^^^/\   2 sec after to process the next request
[ INFO] [1621933198.556201921]:   sending back response: [42]

• make ros1 client call ros2 service via ros1_bridge at the same time if ros2 service is supported with multiple threads(MultiThreadExecutor and a callback with reentrant).

https://github.com/iuhilnehc-ynos/ros2-examples/blob/0acb1b892f318ec7898b812d10765f538c93ebc7/rclcpp/services/minimal_service/main.cpp#L44-L46

running rosservice call /add_two_ints '{a: 3, b: 4}'& rosservice call /add_two_ints '{a: 3, b: 4}' expect to get the service log as following

[INFO] [1621936929.275491886] [minimal_service]: request: 3 + 4
[INFO] [1621936929.275632310] [minimal_service]: request: 3 + 4

without this patch, the log as following,

[INFO] [1621937408.339715576] [minimal_service]: request: 3 + 4
[INFO] [1621937410.340892268] [minimal_service]: request: 3 + 4

Notice that supporting the service with running multiple threads is for not only the one service(a custom callback group with reentrant set by user) but also multiple different services.

Could somebody help to review this PR?

[iuhilnehc-ynos]

The failure about The following signatures were invalid: EXPKEYSIG F42ED6FBAB17C654 Open Robotics <[email protected]> was mentioned on https://answers.ros.org/question/379190/apt-update-signatures-were-invalid-f42ed6fbab17c654/, I'll run retest this please after the CI is fixed.

[fujitatomoya]

@clalancette @sloretz friendly ping.

[fujitatomoya]

@gbiggs you might want to take a look, this fixes https://github.com/ros2/ros1_bridge/issues/314

[joelbudu]

Any chance in this getting merged? @iuhilnehc-ynos @sloretz @clalancette

[iuhilnehc-ynos]

@joelbudu

I am sorry about not figuring out an elegant fix for this. The answer is no for this PR, at least.