build: circleci: switch to 'machine' executor for test-build-in-docker job

refs #356

.circleci/config.yml

@@ -129,29 +129,18 @@ jobs:
     docker:
     - image: circleci/golang:1.14
 
-  # this job tries to mimic the build-in-docker instructions
-  # given in docs/installation.rst
-  #
-  # However, CircleCI doesn't support volume mounts, so we have to copy
-  # the source into the build-container by modifying the Dockerfile
+  # this job tests the build-in-docker instructions
+  # given in docs/installation/compile-from-source.rst
   test-build-in-docker:
     description: Check that build-in-docker works
-    docker:
-      - image: circleci/golang:latest
-    environment:
-    working_directory: /go/src/github.com/zrepl/zrepl
+    machine:
+      image: default
     steps:
     - checkout
-    - setup_remote_docker
+    - run: docker build -t zrepl_build -f build.Dockerfile .
     - run:
-        name: (hacky) circleci doesn't allow volume mounts, so copy src to container
-        command: echo "ADD . /src" >> build.Dockerfile
-    - run:
-        name: (hacky) commit modified Dockerfile to avoid failing git clean check in Makefile
-        command: git -c user.name='circleci' -c user.email='circleci@localhost' commit -m 'CIRCLECI modified Dockerfile with zrepl src' --author 'autoauthor <circleci@localhost>' -- build.Dockerfile
-    - run:
-        name: build the build image (build deps)
-        command: docker build -t zrepl_build -f build.Dockerfile .
-    - run:
-        name: try compiling
-        command: docker run -it zrepl_build make release
+        command: |
+          docker run -it --rm \
+            -v "${PWD}:/src" \
+            --user "$(id -u):$(id -g)" \
+            zrepl_build make release