Update Dockerfile (elastic#1485)

Build tested, verified, and pushed

Dockerfile

@@ -1,16 +1,19 @@
-FROM python:3.6-alpine3.6 as builder
+FROM python:3.7-alpine3.7 as builder
 
 RUN apk --no-cache upgrade && apk --no-cache add build-base tar musl-utils openssl-dev
-RUN pip3 install setuptools cx_Freeze==6.0b1
+RUN pip3 install setuptools cx_Freeze
 
 COPY . .
 RUN ln -s /lib/libc.musl-x86_64.so.1 ldd
 RUN ln -s /lib /lib64
 RUN pip3 install -r requirements.txt
 RUN python3 setup.py build_exe
 
-FROM alpine:3.6
-RUN apk --no-cache upgrade && apk --no-cache add ca-certificates && update-ca-certificates && apk --no-cache add wget
-COPY --from=builder build/exe.linux-x86_64-3.6 /curator/
+FROM alpine:3.7
+RUN apk --no-cache upgrade && apk --no-cache add openssl-dev
+COPY --from=builder build/exe.linux-x86_64-3.7 /curator/
+
 USER nobody:nobody
+ENV LD_LIBRARY_PATH /curator/lib:$LD_LIBRARY_PATH
 ENTRYPOINT ["/curator/curator"]
+

docs/Changelog.rst

@@ -17,6 +17,8 @@ Changelog
 
   * Lots of code cleanup, trying to go PEP-8. All tests are still passing, and
     the APIs are not changed (yet—-that comes in the next major release).
+  * Dockerfile has been updated to produce a working version with Python 3.7
+    and Curator 5.8.1
 
 5.8.1 (25 September 2019)
 -------------------------