Shrink the development environment container

Use a smaller container, based on Alpine

(note: travis-ci has not reported success, but when checking the build,
it is green as can be: https://travis-ci.org/github/xtofl/cpp11training/builds/703191129)

Author: xtofl

docker/Dockerfile

@@ -1,6 +1,6 @@
-FROM ubuntu:18.04
+FROM alpine:3
 
-RUN apt update
-RUN apt install -y gcc-8 cmake
-RUN apt install -y vim git
-RUN apt install -y g++-8
+RUN apk update
+RUN apk add make cmake>=3.11 g++>=9
+RUN apk add vim git
+RUN apk add clang

docker/_typical_workflow.sh

@@ -0,0 +1,14 @@
+#!/bin/sh
+
+set -x
+projectdir=$(cd $(dirname $0)/.. && pwd)
+
+# make a build folder
+cd $(mktemp -d -t cpp11training_build)
+
+# make the project
+cmake $projectdir/src && make
+
+# run the tests
+./cpp11training
+

docker/build-container.bat

@@ -1 +1 @@
-docker build --tag cpp11training %~dp0
+docker build --tag cpp11training %~dp0

docker/build-container.sh

@@ -0,0 +1,5 @@
+#!/bin/bash
+
+cd $(cd $(dirname $0)/..; pwd)
+docker build --tag cpp11training docker
+docker/test_buildimage.sh

docker/test_buildimage.sh

@@ -0,0 +1,13 @@
+#!/bin/sh
+
+# script to test the build container
+#
+# it runs the typical workflow in the build container
+# (cf. _typical_workflow.sh)
+
+project_dir=$(cd $(dirname $0)/..; pwd)
+
+docker build -t xtofl/cpp11training $project_dir/docker
+
+docker run --volume $(pwd):$(pwd) --workdir $(pwd) --rm ${IMAGE:-"xtofl/cpp11training"} /bin/sh docker/_typical_workflow.sh
+