Cache locally-built Homebrew bottles in OSX builds

.travis.yml

@@ -25,6 +25,17 @@ dist: trusty
 git:
     submodules: false
 
+# https://docs.travis-ci.com/user/caching
+cache:
+  directories:
+    # https://stackoverflow.com/questions/39930171/cache-brew-builds-with-travis-ci
+    - $HOME/Library/Caches/Homebrew
+    - /usr/local/Homebrew/
+    # used in OSX custom build script dealing with local bottle caching
+    - $HOME/local_bottle_metadata
+    # `cache: ccache: true` has no effect if `language:` is not `c` or `cpp`
+    - $HOME/.ccache
+
 matrix:
   fast_finish: true
   include:
@@ -513,6 +524,21 @@ before_install: |
     source multibuild_customize.sh
     echo $ENABLE_CONTRIB > contrib.enabled
     echo $ENABLE_HEADLESS > headless.enabled
+
+    if [ -n "$IS_OSX" ]; then
+        TAPS="$(brew --repository)/Library/Taps"
+        if [ -e "$TAPS/caskroom/homebrew-cask" -a -e "$TAPS/homebrew/homebrew-cask" ]; then
+            rm -rf "$TAPS/caskroom/homebrew-cask"
+        fi
+        find "$TAPS" -type d -name .git -exec \
+                bash -xec '
+                    cd $(dirname '\''{}'\'')
+                    git clean -fxd
+                    git status' \;
+
+        brew_cache_cleanup
+    fi
+
     before_install
     # Not interested in travis internal scripts' output
     set +x
@@ -526,9 +552,30 @@ install: |
 script: |
     # Install and run tests
     set -x
-    install_run $PLAT
+    install_run $PLAT && rc=$? || rc=$?
     set +x
 
+    #otherwise, Travis logic terminates prematurely
+    #https://travis-ci.community/t/shell-session-update-command-not-found-in-build-log-causes-build-to-fail-if-trap-err-is-set/817
+    trap ERR
+
+    test "$rc" -eq 0
+
+before_cache: |
+    # Cleanup dirs to be cached
+    set -x
+    if [ -n "$IS_OSX" ]; then
+
+        # When Taps is cached, this dir causes "Error: file exists" on `brew update`
+        if [ -e "$(brew --repository)/Library/Taps/homebrew/homebrew-cask/homebrew-cask" ]; then
+            rm -rf "$(brew --repository)/Library/Taps/homebrew/homebrew-cask/homebrew-cask"
+        fi
+
+        brew_cache_cleanup
+
+    fi
+    set +x
+
 after_success: |
     # Upload wheels to pypi if requested
     if [ -n "$TRAVIS_TAG" ]; then

config.sh

@@ -20,32 +20,58 @@ function bdist_wheel_cmd {
 
 if [ -n "$IS_OSX" ]; then
   echo "    > OSX environment "
+  export MAKEFLAGS="-j$(sysctl -n hw.ncpu)"
 else
   echo "    > Linux environment "
+  export MAKEFLAGS="-j$(grep -E '^processor[[:space:]]*:' /proc/cpuinfo | wc -l)"
+fi
+
+if [ -n "$IS_OSX" ]; then
+
+    source travis_osx_brew_cache.sh
+
+    BREW_SLOW_BUILIDING_PACKAGES=$(printf '%s\n' \
+        "x265 20"  \
+        "cmake 15" \
+        "ffmpeg 10" \
+    )
+
+    #Contrib adds significantly to project's build time
+    if [ "$ENABLE_CONTRIB" -eq 1 ]; then
+        BREW_TIME_LIMIT=$((BREW_TIME_LIMIT - 10*60))
+    fi
+
 fi
 
 function pre_build {
   echo "Starting pre-build"
-  set -e
+  set -e -o pipefail
 
   if [ -n "$IS_OSX" ]; then
     echo "Running for OSX"
+
+    brew update --merge
+    brew_add_local_bottles
+
+    # Don't query analytical info online on `brew info`,
+    #  this takes several seconds and we don't need it
+    # see https://docs.brew.sh/Manpage , "info formula" section
+    export HOMEBREW_NO_GITHUB_API=1
 
-    brew update
+    # https://docs.travis-ci.com/user/caching/#ccache-cache
+    # No need to allow rc 1 -- if this triggers a timeout,
+    #  something is clearly wrong
+    brew_install_and_cache_within_time_limit ccache
+    export PATH="/usr/local/opt/ccache/libexec:$PATH"
 
     echo 'Installing QT4'
-    brew tap | grep -qxF cartr/qt4 || brew tap -v cartr/qt4
-    brew tap --list-pinned | grep -qxF cartr/qt4 || brew tap-pin -v cartr/qt4
-    brew list --versions qt@4 || brew install -v qt@4
-    echo '-----------------'
-    echo '-----------------'
+    brew tap | grep -qxF cartr/qt4 || brew tap cartr/qt4
+    brew tap --list-pinned | grep -qxF cartr/qt4 || brew tap-pin cartr/qt4
+    brew_install_and_cache_within_time_limit qt@4 || { [ $? -gt 1 ] && return 2 || return 0; }
+
     echo 'Installing FFmpeg'
-    # brew install does produce output regularly on a regular MacOS,
-    # but Travis doesn't see it for some reason
-    brew list --versions ffmpeg || \
-    travis_wait brew install -v ffmpeg --without-x264 --without-xvid --without-gpl
-    brew info ffmpeg
-    echo '-----------------'
+
+    brew_install_and_cache_within_time_limit ffmpeg || { [ $? -gt 1 ] && return 2 || return 0; }
 
   else
     echo "Running for linux"