Docker-alpine: python cffi problems with 3.5 & 3.6

[NathanZook]

Trying to build the docker image from https://github.com/samsung-cnct/k2-tools/tree/e0f97d7c79095065a5634595efe962f7d46a1b1f. This is working for 3.4, but not 3.5 or 3.6.

The interesting part of the output is

Package 'libffi', required by 'virtual:world', not found
running install
running build
running build_py
creating build
creating build/lib.linux-x86_64-2.7
creating build/lib.linux-x86_64-2.7/cffi

...

building '_cffi_backend' extension
creating build/temp.linux-x86_64-2.7
creating build/temp.linux-x86_64-2.7/c
gcc -fno-strict-aliasing -Os -fomit-frame-pointer -g -DNDEBUG -Os -fomit-frame-pointer -g -fPIC -DUSE__THREAD -I/usr/include/ffi -I/usr/include/libffi -I/usr/include/python2.7 -c c/_cffi_backend.c -o build/temp.linux-x86_64-2.7/c/_cffi_backend.o
c/_cffi_backend.c:13:17: fatal error: ffi.h: No such file or directory
 #include <ffi.h>

CFFI is a python package to interface with C code.

[NathanZook]

apk add libffi-dev openssl-dev was what I needed to add (to what I already had) to get pip install cffi to run. Thanks to savant on the slack channel for the help!

[jingweicao]

@NathanZook you solved my problem!