You should try saving and restoring your cache data from a third party service:
- an online object storage like Amazon S3
- a simple FTP server
- an Internet available machine with ssh to make a scp
I'm assuming that your cache data is stored inside the ´~/.ccache´ directory
Using Docker multistage build
From some time, Docker supports Multi-stage builds and you can try using it to implement the solution with a single Dockerfile:
Warning: I've not tested it
# STAGE 1 - YOUR ORIGINAL DOCKER FILE CUSTOMIZED
# CACHE_TAG is provided by Docker cloud
# see https://docs.docker.com/docker-cloud/builds/advanced/
# using ARG in FROM requires min v17.05.0-ce
ARG CACHE_TAG=latest
FROM qgis/qgis3-build-deps:${CACHE_TAG} as builder
MAINTAINER Denis Rouzaud <denis.rouzaud@gmail.com>
ENV CC=/usr/lib/ccache/clang
ENV CXX=/usr/lib/ccache/clang++
ENV QT_SELECT=5
COPY . /usr/src/QGIS
WORKDIR /usr/src/QGIS/build
# restore cache
RUN curl -o ccache.tar.bz2 http://my-object-storage/ccache.tar.bz2
RUN tar -xjvf ccache.tar.bz2
COPY --from=downloader /.ccache ~/.ccache
RUN cmake \
-GNinja \
-DCMAKE_INSTALL_PREFIX=/usr \
-DBINDINGS_GLOBAL_INSTALL=ON \
-DWITH_STAGED_PLUGINS=ON \
-DWITH_GRASS=ON \
-DSUPPRESS_QT_WARNINGS=ON \
-DENABLE_TESTS=OFF \
-DWITH_QSPATIALITE=ON \
-DWITH_QWTPOLAR=OFF \
-DWITH_APIDOC=OFF \
-DWITH_ASTYLE=OFF \
-DWITH_DESKTOP=ON \
-DWITH_BINDINGS=ON \
-DDISABLE_DEPRECATED=ON \
.. \
&& ninja install
# save the current cache online
WORKDIR ~/
RUN tar -cvjSf ccache.tar.bz2 .ccache
RUN curl -T ccache.tar.bz2 -X PUT http://my-object-storage/ccache.tar.bz2
# STAGE 2
FROM alpine:latest
# YOUR CUSTOM LOGIC TO CREATE THE FINAL IMAGE WITH ONLY REQUIRED BINARIES
# USE THE FROM IMAGE YOU NEED, this is only an example
# E.g.:
# COPY --from=builder /usr/src/QGIS/build/YOUR_EXECUTABLE /usr/bin
# ...
In the stage 2 you will build the final image that will be pushed to your repository.
Using Docker cloud hooks
Another, but less clear, approach could be using a Docker Cloud pre_build hook file to download cache data:
#!/bin/bash
echo "=> Downloading build cache data"
curl -o ccache.tar.bz2 http://my-object-storage/ccache.tar.bz2 # e.g. Amazon S3 like service
cd /
tar -xjvf ccache.tar.bz2
Obviously you can use dedicate docker images to run curl or tar mounting the local directory as a volume in this script.
Then, copy the .ccache extracted folder inside your container during the build, using a COPY command before your cmake call:
WORKDIR /usr/src/QGIS/build
COPY /.ccache ~/.ccache
RUN cmake ...
In order to make this you should find a way to upload your cache data after the build and you could make this easily using a post_build hook file:
#!/bin/bash
echo "=> Uploading build cache data"
tar -cvjSf ccache.tar.bz2 ~/.ccache
curl -T ccache.tar.bz2 -X PUT http://my-object-storage/ccache.tar.bz2
But your compilation data aren't available from the outside, because they live inside the container. So you should upload the cache after the cmake command inside your main Dockerfile:
RUN cmake...
&& tar ...
&& curl ...
&& ninja ...
&& rm ...
If curl or tar aren't available, just add them to your container using the package manager (qgis/qgis3-build-deps is based on Ubuntu 16.04, so they should be available).
