How to install newer imagemagick with webp support in Travis CI container?

Question

I wanted to convert png images to webp alternatives in travis but Travis CI uses quite old ubuntu version 12.04 so the bundled imagemagick wasn't really up to date:

$ convert -version
Version: ImageMagick 6.6.9-7 2014-03-06 Q16 http://www.imagemagick.org
Copyright: Copyright (C) 1999-2011 ImageMagick Studio LLC
Features: OpenMP

I know that I can use sudo: required to use travis in virtual machine and install and build things over there. Instead I would like to use the containerized build environment with sudo: false because it's much faster.

If I try to compile libwepb or imagemagick travis gives me permission denied errors because I don't have permissions to /usr/local/ folder:

$ make install
...
 /bin/mkdir -p '/usr/local/include/webp'
/bin/mkdir: cannot create directory `/usr/local/include/webp': Permission denied
...
The command "make install" failed and exited with 2 during .

Answer 1

Travis allows users to change $PATH and install binaries into $HOME directory.

Here's complete example for ruby. It only compiles the binaries once and caches them. It only installs them again if the version numbers don't match.

language: ruby
sudo: false
dist: precise

cache:
  directories:
  - "$HOME/opt"

addons:
  apt:
    packages:
      - libjpeg-dev
      - libpng-dev
      - libgif-dev
env:
  global:
  - IMAGEMAGICK_VERSION: '7.0.3-10'
  - LIBWEBP_VERSION: '0.5.1'

# Install newer libwebp and imagemagick
before_install:
  # Update PATH so that travis can find newer imagemagick
  - export PATH=$HOME/opt/bin:$PATH

  # Checks if Imagemagick is already sufficient version
  # If not installs it from the sources
  - convert -version | grep $IMAGEMAGICK_VERSION || {
    export CORES=$(nproc) &&
    echo "Using $CORES cores for compiling..." &&
    cd /tmp &&
    curl -O https://storage.googleapis.com/downloads.webmproject.org/releases/webp/libwebp-$LIBWEBP_VERSION.tar.gz &&
    tar xvzf libwebp-$LIBWEBP_VERSION.tar.gz &&
    cd libwebp-* &&
    ./configure --prefix=$HOME/opt &&
    make -j$CORES &&
    make install -j$CORES &&
    cd /tmp &&
    curl -O https://www.imagemagick.org/download/ImageMagick-$IMAGEMAGICK_VERSION.tar.gz &&
    tar xvzf ImageMagick-$IMAGEMAGICK_VERSION.tar.gz &&
    cd ImageMagick-* &&
    ./configure --prefix=$HOME/opt &&
    make -j$CORES &&
    make install -j$CORES &&
    $HOME/opt/bin/magick -version | grep $IMAGEMAGICK_VERSION &&
    cd $TRAVIS_BUILD_DIR; }

  # Update library paths for programs
  - export LD_FLAGS=-L$HOME/opt/lib
  - export LD_LIBRARY_PATH=/lib:/usr/lib:/usr/local/lib:$HOME/opt/lib
  - export CPATH=$CPATH:$HOME/opt/include

Credits: I looked how this ruby library installs libwebp and figuring out the rest was easy: https://github.com/le0pard/webp-ffi/blob/master/.travis.yml