devstack/Vagrant: cache files missed by vagrant-cachier plugin

When vagrant-cachier is enabled, it caches downloaded files in the host so
that apt-get doesn't have to download them from the internet every time
"vagrant up" is run.

This patch enables the same behaviour for files downloaded by pip, Maven,
Node.js and npm.

OpenStack files are still freshly downloaded via Git clone - this patch
only affects the 3rd-party dependencies.

The result is that, on my laptop via corporate proxy, a "vagrant up" takes
27 minutes instead of > 1 hour.

Change-Id: I5f81a217a30abce9ba2ecea6f3c1884ae40595e2

devstack/Vagrantfile

@@ -71,6 +71,36 @@ Vagrant.configure(2) do |config|
     fi
 
     git clone https://git.openstack.org/openstack-dev/devstack -b master --depth 1
+
+    # If using vagrant-cachier, restore cached downloads of 3rd-party dependencies
+    if [ -d "/tmp/vagrant-cache" ]; then
+        if [ -d "/tmp/vagrant-cache/downloads" ]; then
+          echo "Restoring downloads"
+          cp /tmp/vagrant-cache/downloads/* devstack/files
+        fi
+        if [ -f "/tmp/vagrant-cache/pip-cache.tar.gz" ]; then
+          echo "Restoring ~/.cache"
+          tar xzf /tmp/vagrant-cache/pip-cache.tar.gz -C ~
+        fi
+        if [ -f "/tmp/vagrant-cache/nvm-cache.tar.gz" ]; then
+          echo "Restoring ~/.nvm/.cache"
+          mkdir -p ~/.nvm
+          tar xzf /tmp/vagrant-cache/nvm-cache.tar.gz -C ~/.nvm
+        fi
+        if [ -f "/tmp/vagrant-cache/npm-pkgs.tar.gz" ]; then
+          echo "Restoring ~/.npm"
+          tar xzf /tmp/vagrant-cache/npm-pkgs.tar.gz -C ~
+        fi
+        if [ -f "/tmp/vagrant-cache/root-pip-cache.tar.gz" ]; then
+          echo "Restoring ~root/.cache"
+          sudo tar xzf /tmp/vagrant-cache/root-pip-cache.tar.gz -C ~root
+        fi
+        if [ -f "/tmp/vagrant-cache/root-m2-cache.tar.gz" ]; then
+          echo "Restoring ~root/.m2"
+          sudo tar xzf /tmp/vagrant-cache/root-m2-cache.tar.gz -C ~root
+        fi
+    fi
+
     cd devstack
     echo '[[local|localrc]]
 
@@ -126,6 +156,16 @@ enable_plugin monasca-api https://git.openstack.org/openstack/monasca-api
 
 ' > local.conf
     ./stack.sh
+    # Cache downloaded files for future runs
+    if [ -d "/tmp/vagrant-cache" ]; then
+        mkdir -p /tmp/vagrant-cache/downloads
+        cp files/*gz files/*.deb /tmp/vagrant-cache/downloads
+        tar czf /tmp/vagrant-cache/pip-cache.tar.gz -C ~ .cache
+        tar czf /tmp/vagrant-cache/nvm-cache.tar.gz -C ~/.nvm .cache
+        tar czf /tmp/vagrant-cache/npm-pkgs.tar.gz -C ~ .npm
+        sudo tar czf /tmp/vagrant-cache/root-pip-cache.tar.gz -C ~root .cache
+        sudo tar czf /tmp/vagrant-cache/root-m2-cache.tar.gz -C ~root .m2
+    fi
   SHELL
 
 end