[SOLVED] ModuleNotFoundError: No module named 'my_custom_service_pkg'

IdrisOm · October 19, 2022, 5:05pm

Hi, I have had this Error for quite some time now,
Traceback (most recent call last):
File “/home/user/catkin_ws/src/my_examples_pkg/scripts/custom_service_server.py”, line 4, in
from my_custom_service_pkg.srv import MyCustomServiceMessage, MyCustomServiceMessageResponse # you import the service message python classes
ModuleNotFoundError: No module named ‘my_custom_service_pkg’

I have tried everything that I read on this previous article but it did not help:

girishkumar.kannan · October 20, 2022, 6:13am

Hi @IdrisOm ,

Welcome to the Community!

I understand that you are using ROS1 (since you are in catkin_ws), and I believe that you are on the ROS Basics in 5 Days Python course.

This error that you get usually happens when you have not compiled / built the package with the custom message with catkin_make. You must first build the custom message package before using it in another package.
Please do the above step if you have not done it.

In case, you are sure you did all the steps and you still get this error, then reply with the following:

Upload a picture of your catkin_ws/src folder structure expanded and your current package expanded from the IDE left panel.
Upload your CMakeLists.txt file contents
Upload your package.xml file contents
Upload your launch file contents
What is the node name in your python file? This is the line rospy.init_node("node_name")

To upload file contents, copy paste the file contents between two consecutive lines with 3 grave symbols. You can find this symbol to the left of number 1 in your keyboard, above TAB button and below Esc button.

Example:

# This is a sample code block
#! /usr/env/bin python
print("Hello World!") # prints Hello World! on stdout / screen

```
copy-paste your CMakeLists.txt file contents here
```

```
copy-paste your package.xml file contents here
```

```
copy-paste your .launch file contents here
```

Regards,
Girish

IdrisOm · October 20, 2022, 6:47am

Hi Girish,

yes! I am indeed working with ROS in 5 days python.

Here is the structure of the folder:

cmake_minimum_required(VERSION 3.0.2)
project(my_custom_srv_msg_pkg)

find_package(catkin REQUIRED COMPONENTS
std_msgs
message_generation
)

add_service_files(
FILES
MyCustomServiceMessage.srv
)

generate_messages(
DEPENDENCIES
std_msgs
)

catkin_package(
CATKIN_DEPENDS rospy
)

include_directories(
${catkin_INCLUDE_DIRS}
)

<?xml version="1.0"?> my_custom_srv_msg_pkg 0.0.0 The my_custom_srv_msg_pkg package

user

TODO

<buildtool_depend>catkin</buildtool_depend>
<build_depend>rospy</build_depend>
<build_depend>std_msgs</build_depend>
<build_depend>message_generation</build_depend>
<build_export_depend>rospy</build_export_depend>
<exec_depend>rospy</exec_depend>
<build_export_depend>std_msgs</build_export_depend>
<exec_depend>std_msgs</exec_depend>
<build_export_depend>message_runtime</build_export_depend>
<exec_depend>message_runtime</exec_depend>

and I don’t have a launch file as this is the custom_service_server.py code example from unit 6 that I am trying to run and the node name is “service_client”. But it does not work.

Sincerely
Idris

girishkumar.kannan · October 20, 2022, 7:46am

Hi @IdrisOm ,

Thanks for sharing the file contents.

Your folder structure is fine. However, I am not sure why you are having one package for all python script examples.

Could you post the CMakeLists.txt file contents and package.xml file contents of my_example_package also?
This is where you need to include the custom message package.

Let the already posted contents of my_custom_srv_msg_pkg stay here. Do not edit them or delete them from your post.

Regards,
Girish

IdrisOm · October 20, 2022, 7:54am

Here is the CMakeList file and package file for my_example_pkg.

cmake_minimum_required(VERSION 3.0.2)

project(my_examples_pkg)

## Compile as C++11, supported in ROS Kinetic and newer

# add_compile_options(-std=c++11)

## Find catkin macros and libraries

## if COMPONENTS list like find_package(catkin REQUIRED COMPONENTS xyz)

## is used, also find other catkin packages

find_package(catkin REQUIRED COMPONENTS

rospy

std_msgs

message_generation

)

## System dependencies are found with CMake's conventions

# find_package(Boost REQUIRED COMPONENTS system)

## Uncomment this if the package has a setup.py. This macro ensures

## modules and global scripts declared therein get installed

## See http://ros.org/doc/api/catkin/html/user_guide/setup_dot_py.html

# catkin_python_setup()

################################################

## Declare ROS messages, services and actions ##

################################################

## To declare and build messages, services or actions from within this

## package, follow these steps:

## * Let MSG_DEP_SET be the set of packages whose message types you use in

## your messages/services/actions (e.g. std_msgs, actionlib_msgs, ...).

## * In the file package.xml:

## * add a build_depend tag for "message_generation"

## * add a build_depend and a exec_depend tag for each package in MSG_DEP_SET

## * If MSG_DEP_SET isn't empty the following dependency has been pulled in

## but can be declared for certainty nonetheless:

## * add a exec_depend tag for "message_runtime"

## * In this file (CMakeLists.txt):

## * add "message_generation" and every package in MSG_DEP_SET to

## find_package(catkin REQUIRED COMPONENTS ...)

## * add "message_runtime" and every package in MSG_DEP_SET to

## catkin_package(CATKIN_DEPENDS ...)

## * uncomment the add_*_files sections below as needed

## and list every .msg/.srv/.action file to be processed

## * uncomment the generate_messages entry below

## * add every package in MSG_DEP_SET to generate_messages(DEPENDENCIES ...)

## Generate messages in the 'msg' folder

add_message_files(

FILES

Age.msg

# Message1.msg

# Message2.msg

)

## Generate services in the 'srv' folder

# add_service_files(

# FILES

# Service1.srv

# Service2.srv

# )

## Generate actions in the 'action' folder

#add_action_files(

# FILES

# Action1.action

# Action2.action

#)

## Generate added messages and services with any dependencies listed here

generate_messages(

DEPENDENCIES

std_msgs

)

################################################

## Declare ROS dynamic reconfigure parameters ##

################################################

## To declare and build dynamic reconfigure parameters within this

## package, follow these steps:

## * In the file package.xml:

## * add a build_depend and a exec_depend tag for "dynamic_reconfigure"

## * In this file (CMakeLists.txt):

## * add "dynamic_reconfigure" to

## find_package(catkin REQUIRED COMPONENTS ...)

## * uncomment the "generate_dynamic_reconfigure_options" section below

## and list every .cfg file to be processed

## Generate dynamic reconfigure parameters in the 'cfg' folder

# generate_dynamic_reconfigure_options(

# cfg/DynReconf1.cfg

# cfg/DynReconf2.cfg

# )

###################################

## catkin specific configuration ##

###################################

## The catkin_package macro generates cmake config files for your package

## Declare things to be passed to dependent projects

## INCLUDE_DIRS: uncomment this if your package contains header files

## LIBRARIES: libraries you create in this project that dependent projects also need

## CATKIN_DEPENDS: catkin_packages dependent projects also need

## DEPENDS: system dependencies of this project that dependent projects also need

catkin_package(

# INCLUDE_DIRS include

# LIBRARIES my_examples_pkg

CATKIN_DEPENDS rospy std_msgs message_runtime my_examples_pkg my_custom_srv_msg_pkg

# DEPENDS system_lib

)

###########

## Build ##

###########

## Specify additional locations of header files

## Your package locations should be listed before other locations

include_directories(

# include

${catkin_INCLUDE_DIRS}

)

## Declare a C++ library

# add_library(${PROJECT_NAME}

# src/${PROJECT_NAME}/my_examples_pkg.cpp

# )

## Add cmake target dependencies of the library

## as an example, code may need to be generated before libraries

## either from message generation or dynamic reconfigure

# add_dependencies(${PROJECT_NAME} ${${PROJECT_NAME}_EXPORTED_TARGETS} ${catkin_EXPORTED_TARGETS})

## Declare a C++ executable

## With catkin_make all packages are built within a single CMake context

## The recommended prefix ensures that target names across packages don't collide

# add_executable(${PROJECT_NAME}_node src/my_examples_pkg_node.cpp)

## Rename C++ executable without prefix

## The above recommended prefix causes long target names, the following renames the

## target back to the shorter version for ease of user use

## e.g. "rosrun someones_pkg node" instead of "rosrun someones_pkg someones_pkg_node"

# set_target_properties(${PROJECT_NAME}_node PROPERTIES OUTPUT_NAME node PREFIX "")

## Add cmake target dependencies of the executable

## same as for the library above

# add_dependencies(${PROJECT_NAME}_node ${${PROJECT_NAME}_EXPORTED_TARGETS} ${catkin_EXPORTED_TARGETS})

## Specify libraries to link a library or executable target against

# target_link_libraries(${PROJECT_NAME}_node

# ${catkin_LIBRARIES}

# )

#############

## Install ##

#############

# all install targets should use catkin DESTINATION variables

# See http://ros.org/doc/api/catkin/html/adv_user_guide/variables.html

## Mark executable scripts (Python etc.) for installation

## in contrast to setup.py, you can choose the destination

# catkin_install_python(PROGRAMS

# scripts/my_python_script

# DESTINATION ${CATKIN_PACKAGE_BIN_DESTINATION}

# )

## Mark executables for installation

## See http://docs.ros.org/melodic/api/catkin/html/howto/format1/building_executables.html

# install(TARGETS ${PROJECT_NAME}_node

# RUNTIME DESTINATION ${CATKIN_PACKAGE_BIN_DESTINATION}

# )

## Mark libraries for installation

## See http://docs.ros.org/melodic/api/catkin/html/howto/format1/building_libraries.html

# install(TARGETS ${PROJECT_NAME}

# ARCHIVE DESTINATION ${CATKIN_PACKAGE_LIB_DESTINATION}

# LIBRARY DESTINATION ${CATKIN_PACKAGE_LIB_DESTINATION}

# RUNTIME DESTINATION ${CATKIN_GLOBAL_BIN_DESTINATION}

# )

## Mark cpp header files for installation

# install(DIRECTORY include/${PROJECT_NAME}/

# DESTINATION ${CATKIN_PACKAGE_INCLUDE_DESTINATION}

# FILES_MATCHING PATTERN "*.h"

# PATTERN ".svn" EXCLUDE

# )

## Mark other files for installation (e.g. launch and bag files, etc.)

# install(FILES

# # myfile1

# # myfile2

# DESTINATION ${CATKIN_PACKAGE_SHARE_DESTINATION}

# )

#############

## Testing ##

#############

## Add gtest based cpp test target and link libraries

# catkin_add_gtest(${PROJECT_NAME}-test test/test_my_examples_pkg.cpp)

# if(TARGET ${PROJECT_NAME}-test)

# target_link_libraries(${PROJECT_NAME}-test ${PROJECT_NAME})

# endif()

## Add folders to be run by python nosetests

# catkin_add_nosetests(test)

  <name>my_examples_pkg</name>
  <version>0.0.0</version>
  <description>The my_examples_pkg package</description>

  <!-- One maintainer tag required, multiple allowed, one person per tag -->
  <!-- Example:  -->
  <!-- <maintainer email="jane.doe@example.com">Jane Doe</maintainer> -->
  <maintainer email="user@todo.todo">user</maintainer>


  <!-- One license tag required, multiple allowed, one license per tag -->
  <!-- Commonly used license strings: -->
  <!--   BSD, MIT, Boost Software License, GPLv2, GPLv3, LGPLv2.1, LGPLv3 -->
  <license>TODO</license>


  <!-- Url tags are optional, but multiple are allowed, one per tag -->
  <!-- Optional attribute type can be: website, bugtracker, or repository -->
  <!-- Example: -->
  <!-- <url type="website">http://wiki.ros.org/my_examples_pkg</url> -->


  <!-- Author tags are optional, multiple are allowed, one per tag -->
  <!-- Authors do not have to be maintainers, but could be -->
  <!-- Example: -->
  <!-- <author email="jane.doe@example.com">Jane Doe</author> -->


  <!-- The *depend tags are used to specify dependencies -->
  <!-- Dependencies can be catkin packages or system dependencies -->
  <!-- Examples: -->
  <!-- Use depend as a shortcut for packages that are both build and exec dependencies -->
  <!--   <depend>roscpp</depend> -->
  <!--   Note that this is equivalent to the following: -->
  <!--   <build_depend>roscpp</build_depend> -->
  <!--   <exec_depend>roscpp</exec_depend> -->
  <!-- Use build_depend for packages you need at compile time: -->
  <!--   <build_depend>message_generation</build_depend> -->
  <!-- Use build_export_depend for packages you need in order to build against this package: -->
  <!--   <build_export_depend>message_generation</build_export_depend> -->
  <!-- Use buildtool_depend for build tool packages: -->
  <!--   <buildtool_depend>catkin</buildtool_depend> -->
  <!-- Use exec_depend for packages you need at runtime: -->
  <!--   <exec_depend>message_runtime</exec_depend> -->
  <!-- Use test_depend for packages you need only for testing: -->
  <!--   <test_depend>gtest</test_depend> -->
  <!-- Use doc_depend for packages you need only for building documentation: -->
  <!--   <doc_depend>doxygen</doc_depend> -->
  <buildtool_depend>catkin</buildtool_depend>
  <build_depend>rospy</build_depend>
  <build_depend>std_msgs</build_depend>
  <build_export_depend>rospy</build_export_depend>
  <build_depend>message_generation</build_depend> 
  <exec_depend>rospy</exec_depend>
  <build_export_depend>std_msgs</build_export_depend>
  <exec_depend>std_msgs</exec_depend>
  <build_export_depend>message_runtime</build_export_depend>
  <exec_depend>message_runtime</exec_depend>

  <!-- The export tag contains other, unspecified, tags -->
  <export>
    <!-- Other tools can request additional information be placed here -->

  </export>
</package>

girishkumar.kannan · October 20, 2022, 8:00am

@IdrisOm ,

Could you please use the code block syntax to enclose your file contents? Do you see how huge your reply is? It is hard for us to help you if you can’t do simple steps to help us help you out!

IdrisOm · October 20, 2022, 8:02am

Sorry for that. I thought it was three dashed lines.

girishkumar.kannan · October 20, 2022, 8:04am

Please refer my first reply:

Example:

# This is a sample code block
#! /usr/env/bin python
print("Hello World!") # prints Hello World! on stdout / screen

```
copy-paste your CMakeLists.txt file contents here
```

```
copy-paste your package.xml file contents here
```

IdrisOm · October 20, 2022, 8:05am

I reedited now is it more readable now?

girishkumar.kannan · October 20, 2022, 8:12am

You need to add your custom package under find_package and catkin_package in CMakeLists.txt

find_package(catkin REQUIRED COMPONENTS
rospy
std_msgs
my_custom_srv_msg_pkg
# message_generation not required in this package
)

catkin_package(
# INCLUDE_DIRS include
# LIBRARIES my_examples_pkg
CATKIN_DEPENDS rospy std_msgs my_custom_srv_msg_pkg message_runtime
# DEPENDS system_lib

Add custom package under two dependencies in package.xml

<build_depend>my_custom_srv_msg_pkg</build_depend>
<exec_depend>my_custom_srv_msg_pkg</exec_depend>

These modifications should get it working, I believe.

Let me know if it does not!

Regards,
Girish

IdrisOm · October 20, 2022, 8:21am

I tried it but unfortunately it still does not work:(

Here are the modifications. And then afterwards I compiled it and sourced it but when I ran the code it gave the same error.

cmake_minimum_required(VERSION 3.0.2)
project(my_examples_pkg)

## Compile as C++11, supported in ROS Kinetic and newer
# add_compile_options(-std=c++11)

## Find catkin macros and libraries
## if COMPONENTS list like find_package(catkin REQUIRED COMPONENTS xyz)
## is used, also find other catkin packages
find_package(catkin REQUIRED COMPONENTS
  rospy
  std_msgs
  message_generation
  my_custom_srv_msg_pkg
)

## System dependencies are found with CMake's conventions
# find_package(Boost REQUIRED COMPONENTS system)


## Uncomment this if the package has a setup.py. This macro ensures
## modules and global scripts declared therein get installed
## See http://ros.org/doc/api/catkin/html/user_guide/setup_dot_py.html
# catkin_python_setup()

################################################
## Declare ROS messages, services and actions ##
################################################

## To declare and build messages, services or actions from within this
## package, follow these steps:
## * Let MSG_DEP_SET be the set of packages whose message types you use in
##   your messages/services/actions (e.g. std_msgs, actionlib_msgs, ...).
## * In the file package.xml:
##   * add a build_depend tag for "message_generation"
##   * add a build_depend and a exec_depend tag for each package in MSG_DEP_SET
##   * If MSG_DEP_SET isn't empty the following dependency has been pulled in
##     but can be declared for certainty nonetheless:
##     * add a exec_depend tag for "message_runtime"
## * In this file (CMakeLists.txt):
##   * add "message_generation" and every package in MSG_DEP_SET to
##     find_package(catkin REQUIRED COMPONENTS ...)
##   * add "message_runtime" and every package in MSG_DEP_SET to
##     catkin_package(CATKIN_DEPENDS ...)
##   * uncomment the add_*_files sections below as needed
##     and list every .msg/.srv/.action file to be processed
##   * uncomment the generate_messages entry below
##   * add every package in MSG_DEP_SET to generate_messages(DEPENDENCIES ...)

## Generate messages in the 'msg' folder
add_message_files(
   FILES
   Age.msg
#   Message1.msg
#   Message2.msg
 )

## Generate services in the 'srv' folder
# add_service_files(
#   FILES
#   Service1.srv
#   Service2.srv
# )

## Generate actions in the 'action' folder
#add_action_files(
#   FILES
#   Action1.action
#   Action2.action
#)

## Generate added messages and services with any dependencies listed here
generate_messages(
   DEPENDENCIES
   std_msgs
 )

################################################
## Declare ROS dynamic reconfigure parameters ##
################################################

## To declare and build dynamic reconfigure parameters within this
## package, follow these steps:
## * In the file package.xml:
##   * add a build_depend and a exec_depend tag for "dynamic_reconfigure"
## * In this file (CMakeLists.txt):
##   * add "dynamic_reconfigure" to
##     find_package(catkin REQUIRED COMPONENTS ...)
##   * uncomment the "generate_dynamic_reconfigure_options" section below
##     and list every .cfg file to be processed

## Generate dynamic reconfigure parameters in the 'cfg' folder
# generate_dynamic_reconfigure_options(
#   cfg/DynReconf1.cfg
#   cfg/DynReconf2.cfg
# )

###################################
## catkin specific configuration ##
###################################
## The catkin_package macro generates cmake config files for your package
## Declare things to be passed to dependent projects
## INCLUDE_DIRS: uncomment this if your package contains header files
## LIBRARIES: libraries you create in this project that dependent projects also need
## CATKIN_DEPENDS: catkin_packages dependent projects also need
## DEPENDS: system dependencies of this project that dependent projects also need
catkin_package(
#  INCLUDE_DIRS include
#  LIBRARIES my_examples_pkg
   CATKIN_DEPENDS rospy std_msgs my_examples_pkg my_custom_srv_msg_pkg message_runtime
#  DEPENDS system_lib
)

###########
## Build ##
###########

## Specify additional locations of header files
## Your package locations should be listed before other locations
include_directories(
# include
  ${catkin_INCLUDE_DIRS}
)

## Declare a C++ library
# add_library(${PROJECT_NAME}
#   src/${PROJECT_NAME}/my_examples_pkg.cpp
# )

## Add cmake target dependencies of the library
## as an example, code may need to be generated before libraries
## either from message generation or dynamic reconfigure
# add_dependencies(${PROJECT_NAME} ${${PROJECT_NAME}_EXPORTED_TARGETS} ${catkin_EXPORTED_TARGETS})

## Declare a C++ executable
## With catkin_make all packages are built within a single CMake context
## The recommended prefix ensures that target names across packages don't collide
# add_executable(${PROJECT_NAME}_node src/my_examples_pkg_node.cpp)

## Rename C++ executable without prefix
## The above recommended prefix causes long target names, the following renames the
## target back to the shorter version for ease of user use
## e.g. "rosrun someones_pkg node" instead of "rosrun someones_pkg someones_pkg_node"
# set_target_properties(${PROJECT_NAME}_node PROPERTIES OUTPUT_NAME node PREFIX "")

## Add cmake target dependencies of the executable
## same as for the library above
# add_dependencies(${PROJECT_NAME}_node ${${PROJECT_NAME}_EXPORTED_TARGETS} ${catkin_EXPORTED_TARGETS})

## Specify libraries to link a library or executable target against
# target_link_libraries(${PROJECT_NAME}_node
#   ${catkin_LIBRARIES}
# )

#############
## Install ##
#############

# all install targets should use catkin DESTINATION variables
# See http://ros.org/doc/api/catkin/html/adv_user_guide/variables.html

## Mark executable scripts (Python etc.) for installation
## in contrast to setup.py, you can choose the destination
# catkin_install_python(PROGRAMS
#   scripts/my_python_script
#   DESTINATION ${CATKIN_PACKAGE_BIN_DESTINATION}
# )

## Mark executables for installation
## See http://docs.ros.org/melodic/api/catkin/html/howto/format1/building_executables.html
# install(TARGETS ${PROJECT_NAME}_node
#   RUNTIME DESTINATION ${CATKIN_PACKAGE_BIN_DESTINATION}
# )

## Mark libraries for installation
## See http://docs.ros.org/melodic/api/catkin/html/howto/format1/building_libraries.html
# install(TARGETS ${PROJECT_NAME}
#   ARCHIVE DESTINATION ${CATKIN_PACKAGE_LIB_DESTINATION}
#   LIBRARY DESTINATION ${CATKIN_PACKAGE_LIB_DESTINATION}
#   RUNTIME DESTINATION ${CATKIN_GLOBAL_BIN_DESTINATION}
# )

## Mark cpp header files for installation
# install(DIRECTORY include/${PROJECT_NAME}/
#   DESTINATION ${CATKIN_PACKAGE_INCLUDE_DESTINATION}
#   FILES_MATCHING PATTERN "*.h"
#   PATTERN ".svn" EXCLUDE
# )

## Mark other files for installation (e.g. launch and bag files, etc.)
# install(FILES
#   # myfile1
#   # myfile2
#   DESTINATION ${CATKIN_PACKAGE_SHARE_DESTINATION}
# )

#############
## Testing ##
#############

## Add gtest based cpp test target and link libraries
# catkin_add_gtest(${PROJECT_NAME}-test test/test_my_examples_pkg.cpp)
# if(TARGET ${PROJECT_NAME}-test)
#   target_link_libraries(${PROJECT_NAME}-test ${PROJECT_NAME})
# endif()

## Add folders to be run by python nosetests
# catkin_add_nosetests(test)

<?xml version="1.0"?>
<package format="2">
  <name>my_examples_pkg</name>
  <version>0.0.0</version>
  <description>The my_examples_pkg package</description>

  <!-- One maintainer tag required, multiple allowed, one person per tag -->
  <!-- Example:  -->
  <!-- <maintainer email="jane.doe@example.com">Jane Doe</maintainer> -->
  <maintainer email="user@todo.todo">user</maintainer>


  <!-- One license tag required, multiple allowed, one license per tag -->
  <!-- Commonly used license strings: -->
  <!--   BSD, MIT, Boost Software License, GPLv2, GPLv3, LGPLv2.1, LGPLv3 -->
  <license>TODO</license>


  <!-- Url tags are optional, but multiple are allowed, one per tag -->
  <!-- Optional attribute type can be: website, bugtracker, or repository -->
  <!-- Example: -->
  <!-- <url type="website">http://wiki.ros.org/my_examples_pkg</url> -->


  <!-- Author tags are optional, multiple are allowed, one per tag -->
  <!-- Authors do not have to be maintainers, but could be -->
  <!-- Example: -->
  <!-- <author email="jane.doe@example.com">Jane Doe</author> -->


  <!-- The *depend tags are used to specify dependencies -->
  <!-- Dependencies can be catkin packages or system dependencies -->
  <!-- Examples: -->
  <!-- Use depend as a shortcut for packages that are both build and exec dependencies -->
  <!--   <depend>roscpp</depend> -->
  <!--   Note that this is equivalent to the following: -->
  <!--   <build_depend>roscpp</build_depend> -->
  <!--   <exec_depend>roscpp</exec_depend> -->
  <!-- Use build_depend for packages you need at compile time: -->
  <!--   <build_depend>message_generation</build_depend> -->
  <!-- Use build_export_depend for packages you need in order to build against this package: -->
  <!--   <build_export_depend>message_generation</build_export_depend> -->
  <!-- Use buildtool_depend for build tool packages: -->
  <!--   <buildtool_depend>catkin</buildtool_depend> -->
  <!-- Use exec_depend for packages you need at runtime: -->
  <!--   <exec_depend>message_runtime</exec_depend> -->
  <!-- Use test_depend for packages you need only for testing: -->
  <!--   <test_depend>gtest</test_depend> -->
  <!-- Use doc_depend for packages you need only for building documentation: -->
  <!--   <doc_depend>doxygen</doc_depend> -->
  <buildtool_depend>catkin</buildtool_depend>
  <build_depend>rospy</build_depend>
  <build_depend>std_msgs</build_depend>
  <build_export_depend>rospy</build_export_depend>
  <build_depend>message_generation</build_depend> 
  <exec_depend>rospy</exec_depend>
  <build_export_depend>std_msgs</build_export_depend>
  <exec_depend>std_msgs</exec_depend>
  <build_depend>my_custom_srv_msg_pkg</build_depend>
  <exec_depend>my_custom_srv_msg_pkg</exec_depend>
  <build_export_depend>message_runtime</build_export_depend>
  <exec_depend>message_runtime</exec_depend>
  

  <!-- The export tag contains other, unspecified, tags -->
  <export>
    <!-- Other tools can request additional information be placed here -->

  </export>
</package>

girishkumar.kannan · October 20, 2022, 8:25am

Try adding MyCustomServiceMessage.srv to CMakeLists.txt of my_examples_package

add_service_files(
  FILES
  MyCustomServiceMessage.srv
)

IdrisOm · October 20, 2022, 8:28am

It still does not work.

girishkumar.kannan · October 20, 2022, 8:28am

What is the error that you are getting? Is it the same?

IdrisOm · October 20, 2022, 8:29am

Yeah it is exactly the same as before. It says

rosrun my_examples_pkg custom_service_server.py
Traceback (most recent call last):
  File "/home/user/catkin_ws/src/my_examples_pkg/scripts/custom_service_server.py", line 7, in <module>
    from my_custom_service_pkg.srv import MyCustomServiceMessage, MyCustomServiceMessageResponse
ModuleNotFoundError: No module named 'my_custom_service_pkg'

girishkumar.kannan · October 20, 2022, 8:37am

Add this line to CMakeLists.txt file of my_examples_pkg right under the line that reads:
# add_dependencies(${PROJECT_NAME} ${${PROJECT_NAME}_EXPORTED_TARGETS} ${catkin_EXPORTED_TARGETS})

add_dependencies(my_custom_srv_msg_pkg ${catkin_EXPORTED_TARGETS})

Let me know if this works. I believe, this should!

IdrisOm · October 20, 2022, 8:41am

I added it as such but it still produces the same error.

# add_dependencies(${PROJECT_NAME} ${${PROJECT_NAME}_EXPORTED_TARGETS} 
${catkin_EXPORTED_TARGETS})
add_dependencies(my_custom_srv_msg_pkg ${catkin_EXPORTED_TARGETS})

girishkumar.kannan · October 20, 2022, 8:52am

That is odd! Those above steps should work.

Here is my final modifications that I believe should work!

Modified CMakeLists.txt file for my_examples_pkg.

cmake_minimum_required(VERSION 3.0.2)
project(my_examples_pkg)

## Compile as C++11, supported in ROS Kinetic and newer
# add_compile_options(-std=c++11)

## Find catkin macros and libraries
## if COMPONENTS list like find_package(catkin REQUIRED COMPONENTS xyz)
## is used, also find other catkin packages
find_package(catkin REQUIRED COMPONENTS
  rospy
  std_msgs
)

## System dependencies are found with CMake's conventions
# find_package(Boost REQUIRED COMPONENTS system)


## Uncomment this if the package has a setup.py. This macro ensures
## modules and global scripts declared therein get installed
## See http://ros.org/doc/api/catkin/html/user_guide/setup_dot_py.html
# catkin_python_setup()

################################################
## Declare ROS messages, services and actions ##
################################################

## To declare and build messages, services or actions from within this
## package, follow these steps:
## * Let MSG_DEP_SET be the set of packages whose message types you use in
##   your messages/services/actions (e.g. std_msgs, actionlib_msgs, ...).
## * In the file package.xml:
##   * add a build_depend tag for "message_generation"
##   * add a build_depend and a exec_depend tag for each package in MSG_DEP_SET
##   * If MSG_DEP_SET isn't empty the following dependency has been pulled in
##     but can be declared for certainty nonetheless:
##     * add a exec_depend tag for "message_runtime"
## * In this file (CMakeLists.txt):
##   * add "message_generation" and every package in MSG_DEP_SET to
##     find_package(catkin REQUIRED COMPONENTS ...)
##   * add "message_runtime" and every package in MSG_DEP_SET to
##     catkin_package(CATKIN_DEPENDS ...)
##   * uncomment the add_*_files sections below as needed
##     and list every .msg/.srv/.action file to be processed
##   * uncomment the generate_messages entry below
##   * add every package in MSG_DEP_SET to generate_messages(DEPENDENCIES ...)

## Generate messages in the 'msg' folder
add_message_files(
#   FILES
#   Message1.msg
#   Message2.msg
 )

## Generate services in the 'srv' folder
# add_service_files(
#   FILES
#   Service1.srv
#   Service2.srv
# )

## Generate actions in the 'action' folder
#add_action_files(
#   FILES
#   Action1.action
#   Action2.action
#)

## Generate added messages and services with any dependencies listed here
generate_messages(
   DEPENDENCIES
   std_msgs
 )

################################################
## Declare ROS dynamic reconfigure parameters ##
################################################

## To declare and build dynamic reconfigure parameters within this
## package, follow these steps:
## * In the file package.xml:
##   * add a build_depend and a exec_depend tag for "dynamic_reconfigure"
## * In this file (CMakeLists.txt):
##   * add "dynamic_reconfigure" to
##     find_package(catkin REQUIRED COMPONENTS ...)
##   * uncomment the "generate_dynamic_reconfigure_options" section below
##     and list every .cfg file to be processed

## Generate dynamic reconfigure parameters in the 'cfg' folder
# generate_dynamic_reconfigure_options(
#   cfg/DynReconf1.cfg
#   cfg/DynReconf2.cfg
# )

###################################
## catkin specific configuration ##
###################################
## The catkin_package macro generates cmake config files for your package
## Declare things to be passed to dependent projects
## INCLUDE_DIRS: uncomment this if your package contains header files
## LIBRARIES: libraries you create in this project that dependent projects also need
## CATKIN_DEPENDS: catkin_packages dependent projects also need
## DEPENDS: system dependencies of this project that dependent projects also need
catkin_package(
#  INCLUDE_DIRS include
#  LIBRARIES my_examples_pkg
   CATKIN_DEPENDS rospy std_msgs
#  DEPENDS system_lib
)

###########
## Build ##
###########

## Specify additional locations of header files
## Your package locations should be listed before other locations
include_directories(
# include
  ${catkin_INCLUDE_DIRS}
)

## Declare a C++ library
# add_library(${PROJECT_NAME}
#   src/${PROJECT_NAME}/my_examples_pkg.cpp
# )

## Add cmake target dependencies of the library
## as an example, code may need to be generated before libraries
## either from message generation or dynamic reconfigure
# add_dependencies(${PROJECT_NAME} ${${PROJECT_NAME}_EXPORTED_TARGETS} ${catkin_EXPORTED_TARGETS})

add_dependencies(my_custom_srv_msg_pkg ${catkin_EXPORTED_TARGETS})

## Declare a C++ executable
## With catkin_make all packages are built within a single CMake context
## The recommended prefix ensures that target names across packages don't collide
# add_executable(${PROJECT_NAME}_node src/my_examples_pkg_node.cpp)

## Rename C++ executable without prefix
## The above recommended prefix causes long target names, the following renames the
## target back to the shorter version for ease of user use
## e.g. "rosrun someones_pkg node" instead of "rosrun someones_pkg someones_pkg_node"
# set_target_properties(${PROJECT_NAME}_node PROPERTIES OUTPUT_NAME node PREFIX "")

## Add cmake target dependencies of the executable
## same as for the library above
# add_dependencies(${PROJECT_NAME}_node ${${PROJECT_NAME}_EXPORTED_TARGETS} ${catkin_EXPORTED_TARGETS})

## Specify libraries to link a library or executable target against
# target_link_libraries(${PROJECT_NAME}_node
#   ${catkin_LIBRARIES}
# )

#############
## Install ##
#############

# all install targets should use catkin DESTINATION variables
# See http://ros.org/doc/api/catkin/html/adv_user_guide/variables.html

## Mark executable scripts (Python etc.) for installation
## in contrast to setup.py, you can choose the destination
# catkin_install_python(PROGRAMS
#   scripts/my_python_script
#   DESTINATION ${CATKIN_PACKAGE_BIN_DESTINATION}
# )

## Mark executables for installation
## See http://docs.ros.org/melodic/api/catkin/html/howto/format1/building_executables.html
# install(TARGETS ${PROJECT_NAME}_node
#   RUNTIME DESTINATION ${CATKIN_PACKAGE_BIN_DESTINATION}
# )

## Mark libraries for installation
## See http://docs.ros.org/melodic/api/catkin/html/howto/format1/building_libraries.html
# install(TARGETS ${PROJECT_NAME}
#   ARCHIVE DESTINATION ${CATKIN_PACKAGE_LIB_DESTINATION}
#   LIBRARY DESTINATION ${CATKIN_PACKAGE_LIB_DESTINATION}
#   RUNTIME DESTINATION ${CATKIN_GLOBAL_BIN_DESTINATION}
# )

## Mark cpp header files for installation
# install(DIRECTORY include/${PROJECT_NAME}/
#   DESTINATION ${CATKIN_PACKAGE_INCLUDE_DESTINATION}
#   FILES_MATCHING PATTERN "*.h"
#   PATTERN ".svn" EXCLUDE
# )

## Mark other files for installation (e.g. launch and bag files, etc.)
# install(FILES
#   # myfile1
#   # myfile2
#   DESTINATION ${CATKIN_PACKAGE_SHARE_DESTINATION}
# )

#############
## Testing ##
#############

## Add gtest based cpp test target and link libraries
# catkin_add_gtest(${PROJECT_NAME}-test test/test_my_examples_pkg.cpp)
# if(TARGET ${PROJECT_NAME}-test)
#   target_link_libraries(${PROJECT_NAME}-test ${PROJECT_NAME})
# endif()

## Add folders to be run by python nosetests
# catkin_add_nosetests(test)

Modified package.xml file for my_examples_pkg.

<?xml version="1.0"?>
<package format="2">
  <name>my_examples_pkg</name>
  <version>0.0.0</version>
  <description>The my_examples_pkg package</description>

  <!-- One maintainer tag required, multiple allowed, one person per tag -->
  <!-- Example:  -->
  <!-- <maintainer email="jane.doe@example.com">Jane Doe</maintainer> -->
  <maintainer email="user@todo.todo">user</maintainer>


  <!-- One license tag required, multiple allowed, one license per tag -->
  <!-- Commonly used license strings: -->
  <!--   BSD, MIT, Boost Software License, GPLv2, GPLv3, LGPLv2.1, LGPLv3 -->
  <license>TODO</license>


  <!-- Url tags are optional, but multiple are allowed, one per tag -->
  <!-- Optional attribute type can be: website, bugtracker, or repository -->
  <!-- Example: -->
  <!-- <url type="website">http://wiki.ros.org/my_examples_pkg</url> -->


  <!-- Author tags are optional, multiple are allowed, one per tag -->
  <!-- Authors do not have to be maintainers, but could be -->
  <!-- Example: -->
  <!-- <author email="jane.doe@example.com">Jane Doe</author> -->


  <!-- The *depend tags are used to specify dependencies -->
  <!-- Dependencies can be catkin packages or system dependencies -->
  <!-- Examples: -->
  <!-- Use depend as a shortcut for packages that are both build and exec dependencies -->
  <!--   <depend>roscpp</depend> -->
  <!--   Note that this is equivalent to the following: -->
  <!--   <build_depend>roscpp</build_depend> -->
  <!--   <exec_depend>roscpp</exec_depend> -->
  <!-- Use build_depend for packages you need at compile time: -->
  <!--   <build_depend>message_generation</build_depend> -->
  <!-- Use build_export_depend for packages you need in order to build against this package: -->
  <!--   <build_export_depend>message_generation</build_export_depend> -->
  <!-- Use buildtool_depend for build tool packages: -->
  <!--   <buildtool_depend>catkin</buildtool_depend> -->
  <!-- Use exec_depend for packages you need at runtime: -->
  <!--   <exec_depend>message_runtime</exec_depend> -->
  <!-- Use test_depend for packages you need only for testing: -->
  <!--   <test_depend>gtest</test_depend> -->
  <!-- Use doc_depend for packages you need only for building documentation: -->
  <!--   <doc_depend>doxygen</doc_depend> -->
  <buildtool_depend>catkin</buildtool_depend>
  <build_depend>rospy</build_depend>
  <build_depend>std_msgs</build_depend>
  <build_export_depend>rospy</build_export_depend>
  <build_export_depend>std_msgs</build_export_depend>
  <exec_depend>rospy</exec_depend>
  <exec_depend>std_msgs</exec_depend>
  

  <!-- The export tag contains other, unspecified, tags -->
  <export>
    <!-- Other tools can request additional information be placed here -->

  </export>
</package>

These are modified based on this link: ROS/Tutorials/DefiningCustomMessages - ROS Wiki

If these steps do not work, then as a last resort, you must create the package from scratch.

Your problem is basically “How to use custom message from another ROS package”.

Regards,
Girish

IdrisOm · October 20, 2022, 8:55am

I have created the my_custom_srv_pkg from scratch for more than three times and followed the steps exactly as they did in the tutorial but it still did not work. That is why asked here as a last resort. Could there be some internal problems, I have seen online that many others had the same issues.

girishkumar.kannan · October 20, 2022, 9:01am

I have actually done this (using custom message from another package with both ROS 1 and 2) and have not faced any issues. Although, I did struggle a bit when I first got to learn it.

Your best final option that I would say (if you do not want to redo things from scratch) is that:
Upload only your my_custom_srv_msg_pkg and my_examples_pkg here (I believe you can upload files here).

And I / we can run your packages in our machines, fix it, and then re-upload it back to you with changes that we made.

Regards,
Girish

[SOLVED] ModuleNotFoundError: No module named 'my_custom_service_pkg'

include_directories( ${catkin_INCLUDE_DIRS} )

include_directories(
${catkin_INCLUDE_DIRS}
)