docker: Rely on caching

It seems less likely that tox and tox-pyenv will change than our
requirements. Split up the 'RUN' steps so we don't have to reinstall the
former every time the latter change.

Signed-off-by: Stephen Finucane <stephen@that.guru>

2 files changed, 6 insertions, 7 deletions

diff --git a/tools/docker/Dockerfile b/tools/docker/Dockerfile
index 35324b1..550871b 100644
--- a/tools/docker/Dockerfile
+++ b/tools/docker/Dockerfile
@@ -47,15 +47,14 @@ RUN pyenv latest install 2.7 && \
     pyenv latest install 3.5 && \
     pyenv latest install 3.6 && \
     pyenv latest install 3.7
-
 RUN pyenv global $(pyenv versions --bare | tac)
 
-COPY requirements-*.txt /tmp/
-RUN pip install tox tox-pyenv && \
-    pip install -r /tmp/requirements-dev.txt
+RUN pip install tox tox-pyenv
 
-# we deliberately leave the requirements files in tmp so we can
-# ping the user in entrypoint.sh if the change them!
+# we deliberately leave the requirements files in /opt so we can ping the user
+# in entrypoint.sh if they change
+COPY requirements-dev.txt requirements-test.txt /opt/
+RUN pip install -r /opt/requirements-dev.txt
 
 COPY tools/docker/entrypoint.sh /usr/local/bin/entrypoint.sh
 ENTRYPOINT ["/usr/local/bin/entrypoint.sh"]
diff --git a/tools/docker/entrypoint.sh b/tools/docker/entrypoint.sh
index 456d640..6314f1b 100755
--- a/tools/docker/entrypoint.sh
+++ b/tools/docker/entrypoint.sh
@@ -70,7 +70,7 @@ fi
 set +e
 
 # check if we need to rebuild because requirements changed
-for x in /tmp/requirements-*.txt; do
+for x in /opt/requirements-*.txt; do
     if ! cmp $x ~/patchwork/$(basename $x); then
         cat << EOF
 A requirements file has changed.