如何在 snapcraft 中从创建二进制文件 "part" 引用创建库的 "part" 文件？

Question

我有一个 snap，它将创建一个由多个二进制文件共享的库（在同一个 snap 中）。构建支持此功能的 snap 部件的最佳方式是什么？

以下是我的起点。

parts:
  libwhatever:
    plugin: cmake
    source: ...
    configflags: [
      ...
    ]
    build-packages:
      - liblog4cxx-dev
      - libboost-system-dev
      - libboost-filesystem-dev
      - libboost-thread-dev

  binwhatever:
    plugin: cmake
    source: binwhatever
    configflags: [
    ]
    build-packages:
      - liblog4cxx-dev
      - libboost-system-dev
      - libboost-filesystem-dev
      - libboost-test-dev
      - libboost-thread-dev
      - libgstreamer1.0-dev
      - #how can I reference libwhatever here?

Answer 1

好的，这是可以做到的，但考虑到工具的当前状态，它还没有达到应有的水平。截至本 post 日期需要考虑的几件事：

1) Snap cmake 插件不允许您在构建发生之前定义环境变量（snapcraftctl 在运行之前丢弃环境）——除非您完全覆盖它。所以下面的解决方案采用了在不修改每个二进制文件cmake环境的情况下运行的方法。

2) 据我所知，snapcraft.yaml 确实没有办法知道 "libwhatever"，因为它在构建开始时不存在。因此，snapcraft.yaml 中每个二进制文件对 libwhatever 的所有引用都被删除。

3) 为了使下面的解决方案起作用，"libwhatever" 必须允许给出安装前缀。这允许我们将它编译到 /usr 而不是 /usr/local 或 /opt 或任何地方，并且当构建二进制文件时 "libwhatever" 将被发现。

snapcraft.yaml:

name: project-whatever
version: "6.0.0" 
summary: ""
description: |
  show how to use a common libwhatever among one or more binaries 
  in a snap
grade: devel
confinement: devmode

parts:
  libwhatever:
    plugin: cmake
    source: libwhatever
    configflags: [
      -DCMAKE_BUILD_TYPE=Debug,
      -DCMAKE_INSTALL_PREFIX=/usr
    ]
    build-packages:
      - liblog4cxx-dev
      - libboost-system-dev
      - libboost-filesystem-dev
      - libboost-test-dev
      - libboost-thread-dev
      - libgstreamer1.0-dev
      - libpthread-stubs0-dev
      - libglib2.0-dev
    stage-packages:
      - libc6
      - libgstreamer1.0-0
      - gstreamer1.0-plugins-base-apps
      - liblog4cxx10v5
      - libglib2.0-0

  binwhatever:
    after:
      - libwhatever
    plugin: cmake
    source: binwhatever
    configflags: [
      -DCMAKE_BUILD_TYPE=Debug,
      -DCMAKE_INSTALL_PREFIX=/opt/whatever
      ]
    build-packages:
      - liblog4cxx-dev
      - libboost-system-dev
      - libboost-filesystem-dev
      - libboost-test-dev
      - libboost-thread-dev
      - libboost-program-options-dev
      - libgstreamer1.0-dev
      - libgstreamer-plugins-base1.0-dev
    stage-packages:
      - libc6
      - libgstreamer1.0-0
      - gstreamer1.0-plugins-base-apps
      - liblog4cxx10v5
      - libboost-system1.65.1
      - libboost-filesystem1.65.1
      - libboost-thread1.65.1
      - libboost-program-options1.65.1

CMakeLists.txt for libwhatever（你可以看到尊重-DCMAKE_INSTALL_PREFIX给出的内容）：

cmake_minimum_required(VERSION 3.10)

set(VERSION_MAJOR 1)
set(VERSION_MINOR 2)
set(VERSION_PATCH 0)

project(whatever VERSION "${VERSION_MAJOR}.${VERSION_MINOR}.${VERSION_PATCH}" DESCRIPTION "whatever")

set(CMAKE_CXX_FLAGS "-std=gnu++11")

include(FindPkgConfig)
include(GNUInstallDirs)

set(REQUIRED_LIBS gstreamer-1.0 liblog4cxx pthread-stubs glib-2.0)
pkg_check_modules(ALL REQUIRED ${REQUIRED_LIBS})
find_package(Boost REQUIRED COMPONENTS system filesystem regex thread)

add_library(whatever-shared SHARED whatever.cpp)

set_target_properties(whatever-shared PROPERTIES VERSION ${PROJECT_VERSION})
set_target_properties(whatever-shared PROPERTIES SOVERSION ${VERSION_MAJOR})
set_target_properties(whatever-shared PROPERTIES PUBLIC_HEADER whatever.h)

target_include_directories(whatever-shared PUBLIC ${ALL_INCLUDE_DIRS} PUBLIC ${Boost_INCLUDE_DIRS})
link_directories(whatever-shared PUBLIC ${ALL_LIBRARY_DIRS} PUBLIC ${Boost_LIBRARY_DIRS})
target_link_libraries(whatever-shared ${ALL_LIBRARIES} ${Boost_LIBRARIES})

function(JOIN OUTPUT GLUE)
  set(_TMP_RESULT "")
  set(_GLUE "") # effective glue is empty at the beginning
  foreach(arg ${ARGN})
    set(_TMP_RESULT "${_TMP_RESULT}${_GLUE}${arg}")
    set(_GLUE "${GLUE}")
  endforeach()
  set(${OUTPUT} "${_TMP_RESULT}" PARENT_SCOPE)
endfunction()

join(PKG_CONFIG_REQUIRED_LIBS_STR " " ${REQUIRED_LIBS})
set(PKG_CONFIG_LDFLAGS)
set(PKG_CONFIG_LDFLAGS_STR "-lboost_system -lboost_thread -lboost_regex -lboost_filesystem")
configure_file(libwhatever.pc.in libwhatever.pc @ONLY)

install(TARGETS whatever-shared
  RUNTIME DESTINATION ${CMAKE_INSTALL_BINDIR}
  LIBRARY DESTINATION ${CMAKE_INSTALL_LIBDIR}
  ARCHIVE DESTINATION ${CMAKE_INSTALL_LIBDIR}
  PUBLIC_HEADER DESTINATION ${CMAKE_INSTALL_INCLUDEDIR})

install(FILES ${CMAKE_BINARY_DIR}/libwhatever.pc
  DESTINATION ${CMAKE_INSTALL_DATAROOTDIR}/pkgconfig)

libwhatever.pc.in:

prefix=@CMAKE_INSTALL_PREFIX@
exec_prefix=@CMAKE_INSTALL_PREFIX@
libdir=${exec_prefix}/@CMAKE_INSTALL_LIBDIR@
includedir=${prefix}/@CMAKE_INSTALL_INCLUDEDIR@

Name: @PROJECT_NAME@
Description: @PROJECT_DESCRIPTION@
Version: @PROJECT_VERSION@

Requires: @PKG_CONFIG_REQUIRED_LIBS_STR@
Libs: -L${libdir} -lwhatever @PKG_CONFIG_LDFLAGS_STR@
Cflags: -I${includedir} @PKG_CONFIG_CFLAGS_STR@

现在每个CMakeLists.txt for each binary就能成功找到libwhatever:

pkg_check_modules(ALL REQUIRED libwhatever gstreamer-video-1.0 gstreamer-app-1.0)

如何在 snapcraft 中从创建二进制文件 "part" 引用创建库的 "part" 文件？

How to reference library-creating "part" files from a binary-creating "part" in snapcraft?

snapcraft