you need to `pip install celery[sqs]` to get the additional
dependencies that celery needs to use SQS queues - there are two libs -
boto3 and pycurl.
pycurl is a bunch of python handles around curl, so needs to be
installed from source so it can link to your curl/ssl libs. On paas and
in docker this works fine (needed to add `libcurl4-openssl-dev` to the
docker container), but on macos it can't find openssl. We need to pass
a couple of flags in:
* set the environment variable PYCURL_SSL_LIBRARY=openssl
* pass in the global options `build_ext` and `-I{openssl_headers_path}`.
As shown here:
https://github.com/pycurl/pycurl/issues/530#issuecomment-395403253
Env var is no biggie, but using any install-option flags disables
wheels for the whole pip install run. (See
https://github.com/pypa/pip/issues/2677 and
https://github.com/pypa/pip/issues/4118 for more context on the
install-options flags). A whole bunch of our dependencies don't
install nicely from source (but do from wheel), so this commit installs
pycurl separately as an initial step, with the requisite flags, and
then installs the rest of the requirements as before.
I've updated the makefile and bootstrap.sh files to reflect this, but
if you run `pip install -r requirements.txt` from scratch you will run
into issues.
