Task 9048: Added comments

Docker/CMakeLists.txt

@@ -5,20 +5,32 @@ lofar_package(Docker 1.0)
 include(LofarFindPackage)
 lofar_find_package(Subversion REQUIRED)
 
-# Create our template engine, using build-specific info
-configure_file(
-  ${CMAKE_CURRENT_SOURCE_DIR}/template.in
-  ${CMAKE_CURRENT_BINARY_DIR}/template @ONLY)
+#
+# For given directories, we generate the Dockerfile
+# by parsing their Dockerfile.tmpl through "template".
+#
+# "template" is a script that fills in variables with
+# respect to the build info (branch name, build time, etc)
+#
 
 # Directories with Dockerfile.tmpl to parse
 set(DOCKER_TEMPLATE_DIRS
   lofar-pipeline
   lofar-outputproc)
 
+# Create our template engine, using build-specific info
+configure_file(
+  ${CMAKE_CURRENT_SOURCE_DIR}/template.in
+  ${CMAKE_CURRENT_BINARY_DIR}/template @ONLY)
+
 # Convert Dockerfile.tmpl -> Dockerfile in ${DOCKER_TEMPLATE_DIRS}
 foreach(_dir ${DOCKER_TEMPLATE_DIRS})
+  # _src -> _dst
   set(_src ${CMAKE_CURRENT_SOURCE_DIR}/${_dir}/Dockerfile.tmpl)
   set(_dst ${CMAKE_CURRENT_BINARY_DIR}/${_dir}_Dockerfile)
+
+  # add generating command, and (any) target to force the generation
+  # when "all" is build.
   add_custom_command(
     OUTPUT ${_dst}
     COMMAND ${CMAKE_CURRENT_BINARY_DIR}/template < ${_src} > ${_dst}
@@ -26,6 +38,7 @@ foreach(_dir ${DOCKER_TEMPLATE_DIRS})
   )
   add_custom_target(${_dir}_Dockerfile_target ALL DEPENDS ${_dst})
 
+  # install resulting Dockerfile
   install(FILES
     ${_dst}
     DESTINATION share/docker/${_dir}
@@ -33,10 +46,11 @@ foreach(_dir ${DOCKER_TEMPLATE_DIRS})
   )
 endforeach()
 
-# Install everything
+# Install everything else
 install(DIRECTORY
   lofar-base
   lofar-pipeline
   lofar-outputproc
   DESTINATION share/docker
   PATTERN Dockerfile.tmpl EXCLUDE)
+