alpine caching in vagga (with Alpine as distribution)

initial-alpine.log

% ls -A
vagga.yaml
% cat vagga.yaml
containers:
  test:
    setup:
    - !Depends rebuild.txt
    - !Alpine v3.2
    - !Install [gcc]

commands:
  gcc: !Command
    container: test
    run: "gcc --version"
% echo 1 >rebuild.txt
% vagga gcc
(1/1) Installing alpine-keys (1.1-r0)
OK: 0 MiB in 1 packages
fetch http://dl-3.alpinelinux.org/alpine/v3.2/main/x86_64/APKINDEX.tar.gz
(1/15) Installing musl (1.1.11-r2)
(2/15) Installing busybox (1.23.2-r0)
Executing busybox-1.23.2-r0.post-install
(3/15) Installing alpine-baselayout (2.3.2-r0)
Executing alpine-baselayout-2.3.2-r0.pre-install
Executing alpine-baselayout-2.3.2-r0.post-install
(4/15) Installing openrc (0.15.1-r3)
Executing openrc-0.15.1-r3.post-install
(5/15) Installing alpine-conf (3.2.1-r6)
(6/15) Installing zlib (1.2.8-r1)
(7/15) Installing libcrypto1.0 (1.0.2h-r0)
(8/15) Installing libssl1.0 (1.0.2h-r0)
(9/15) Installing apk-tools (2.6.3-r0)
(10/15) Installing busybox-initscripts (2.2-r28)
Executing busybox-initscripts-2.2-r28.post-install
(11/15) Installing scanelf (0.9.1-r0)
(12/15) Installing musl-utils (1.1.11-r2)
(13/15) Installing libc-utils (0.7-r0)
(14/15) Installing alpine-keys (1.1-r0)
(15/15) Installing alpine-base (3.2.3-r0)
Executing busybox-1.23.2-r0.trigger
OK: 6 MiB in 15 packages
(1/11) Installing binutils-libs (2.25-r3)
(2/11) Installing binutils (2.25-r3)
(3/11) Installing libgomp (4.9.2-r6)
(4/11) Installing pkgconf (0.9.11-r0)
(5/11) Installing pkgconfig (0.25-r1)
(6/11) Installing libgcc (4.9.2-r6)
(7/11) Installing gmp (6.0.0a-r0)
(8/11) Installing mpfr3 (3.1.2-r0)
(9/11) Installing mpc1 (1.0.1-r0)
(10/11) Installing libstdc++ (4.9.2-r6)
(11/11) Installing gcc (4.9.2-r6)
Executing busybox-1.23.2-r0.trigger
OK: 67 MiB in 26 packages
OK: 67 MiB in 26 packages
gcc (Alpine 4.9.2) 4.9.2
Copyright (C) 2014 Free Software Foundation, Inc.
This is free software; see the source for copying conditions.  There is NO
warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.

rerun-alpine.log

% echo 2 >rebuild.txt
% vagga gcc
(1/1) Installing alpine-keys (1.1-r0)
OK: 0 MiB in 1 packages
fetch http://dl-8.alpinelinux.org/alpine/v3.2/main/x86_64/APKINDEX.tar.gz
(1/15) Installing musl (1.1.11-r2)
(2/15) Installing busybox (1.23.2-r0)
Executing busybox-1.23.2-r0.post-install
(3/15) Installing alpine-baselayout (2.3.2-r0)
Executing alpine-baselayout-2.3.2-r0.pre-install
Executing alpine-baselayout-2.3.2-r0.post-install
(4/15) Installing openrc (0.15.1-r3)
Executing openrc-0.15.1-r3.post-install
(5/15) Installing alpine-conf (3.2.1-r6)
(6/15) Installing zlib (1.2.8-r1)
(7/15) Installing libcrypto1.0 (1.0.2h-r0)
(8/15) Installing libssl1.0 (1.0.2h-r0)
(9/15) Installing apk-tools (2.6.3-r0)
(10/15) Installing busybox-initscripts (2.2-r28)
Executing busybox-initscripts-2.2-r28.post-install
(11/15) Installing scanelf (0.9.1-r0)
(12/15) Installing musl-utils (1.1.11-r2)
(13/15) Installing libc-utils (0.7-r0)
(14/15) Installing alpine-keys (1.1-r0)
(15/15) Installing alpine-base (3.2.3-r0)
Executing busybox-1.23.2-r0.trigger
OK: 6 MiB in 15 packages
(1/11) Installing binutils-libs (2.25-r3)
(2/11) Installing binutils (2.25-r3)
(3/11) Installing libgomp (4.9.2-r6)
(4/11) Installing pkgconf (0.9.11-r0)
(5/11) Installing pkgconfig (0.25-r1)
(6/11) Installing libgcc (4.9.2-r6)
(7/11) Installing gmp (6.0.0a-r0)
(8/11) Installing mpfr3 (3.1.2-r0)
(9/11) Installing mpc1 (1.0.1-r0)
(10/11) Installing libstdc++ (4.9.2-r6)
(11/11) Installing gcc (4.9.2-r6)
Executing busybox-1.23.2-r0.trigger
OK: 67 MiB in 26 packages
OK: 67 MiB in 26 packages
gcc (Alpine 4.9.2) 4.9.2
Copyright (C) 2014 Free Software Foundation, Inc.
This is free software; see the source for copying conditions.  There is NO
warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.