Add conditional build of jf-live-writer

jf-live-writer requires PHDF5, which is not very popular
on development machines. If you want to enable this, you have
to pass BUILD_JF_LIVE_WRITER=ON to cmake. See the README.

CMakeLists.txt

@@ -34,5 +34,8 @@ add_subdirectory("jf-buffer-writer")
 add_subdirectory("jf-assembler")
 add_subdirectory("sf-stream")
 add_subdirectory("sf-writer")
-#add_subdirectory("jf-live-writer")
+
+if(BUILD_JF_LIVE_WRITER)
+        add_subdirectory("jf-live-writer")
+endif()
 

jf-live-writer/Dockerfile

@@ -23,4 +23,4 @@ WORKDIR /
 RUN git clone --depth 1 --branch ${branch} https://github.com/paulscherrerinstitute/sf_daq_buffer.git
 RUN mkdir /sf_daq_buffer/build
 WORKDIR /sf_daq_buffer/build
-RUN cmake3 .. && make jf-live-writer
+RUN cmake3 -DBUILD_JF_LIVE_WRITER=ON .. && make jf-live-writer

jf-live-writer/README.md

@@ -1,5 +1,16 @@
 # jf-live-writer
 
+The jf-live-writer is packaged as a Docker container for development and 
+testing.
+
+## Building
+In order to build this executable you need to specify the cmake variable
+```
+cmake3 -DBUILD_JF_LIVE_WRITER=ON 
+```
+The project will not build if you do not have installed the PHDF5 library.
+Please follow instructions below on how to do that manually.
+
 ## Install PHDF5 manually 
 ```
 wget https://support.hdfgroup.org/ftp/HDF5/releases/hdf5-1.12/hdf5-1.12.0/src/hdf5-1.12.0.tar.gz