Started adding support for offline installer image

- If geninstaller is run with -o or --offline, then during generate_img,
    chroot into target and run apt-get install with all required packges for
    subiquity.
  - At the moment, cloud-init will still attempt to install packages when it
    boots without network, then fail over to the next part of the init, and
    eventually will run subiquity.
  - While this is functional for an offline installer, it is preferrable to
    tell cloud-init not to try to install packages, to avoid extra delays
    and to keep errors out of the cloud-init log

installer/geninstaller

@@ -33,6 +33,13 @@ SRC_DEPS=(
   "bzr" "lp:~wesley-wiedenmeier/curtin/custom-partitioning-layout" "curtin"
   "git" "https://github.com/CanonicalLtd/probert.git" "probert"
 )
+INSTALLER_DEPS=(
+  "python3-parted"
+  "python3-urwid"
+  "python3-pyudev"
+  "python3-netifaces"
+  "python-urwid"
+)
 CACHEDIR=""
 
 cleanup_noexit() {
@@ -102,6 +109,7 @@ usage: $PROG [PARAMS] [ARGS]
  -a, --arch=ARCH                For ARCH in [i386, amd64, ppc64el, armf, arm64]
  -b, --bootloader=TYPE          For TYPE in [syslinux, grub2, uboot]
  -h, --help                     This output.
+ -o, --offline                  Offline installer img.
  -r, --release=RELEASE          For RELEASE in  [trusty, utopic, vivid, wily]
  -s, --stream=STREAM            For STREAM in [daily, released]
  -V, --version=VERSION          VERSION=YYYYMMDD , 20150623
@@ -284,7 +292,7 @@ acquire_image() {
 
 generate_seed() {
     _RETVAL=""
-    [ $# -lt 2 ] && {
+    [ $# -lt 3 ] && {
         log "ERROR: not enough arguments passed to $FUNCNAME";
         return 1;
     }
@@ -293,6 +301,7 @@ generate_seed() {
     local cachedir=${2};
     local seed=$cachedir/seed/nocloud-net
     local installer_user_data=${TOPDIR}/resources/user-data/installer-user-data
+    local installer_user_data_offline=${TOPDIR}/resources/user-data/installer-offline-data
 
     # create curtin payload
     log "Generating curtin payload file"
@@ -317,6 +326,11 @@ generate_seed() {
     # append the curtin-cmd file
     rm -f ${seed}/user-data &&
     cp $installer_user_data $seed/user-data &&
+
+    if [ "${OFFLINE}" == "yes" ]; then
+        log "Disabling package_update/upgrade"
+    fi
+
     userdata_write_file "/usr/local/bin/curtin-archive" \
                          "root:root" "0755" "none" \
                          "$curtin_cmd" >> $seed/user-data || {
@@ -355,7 +369,7 @@ generate_seed() {
 
 generate_img() {
     _RETVAL=""
-    [ $# -lt 3 ] && {
+    [ $# -lt 4 ] && {
         log "ERROR: not enough arguments passed to $FUNCNAME";
         return 1;
     }
@@ -444,6 +458,20 @@ generate_img() {
     sudo mount none -t sysfs ${mnt}/sys &&
     sudo mount -o bind /dev ${mnt}/dev &&
 
+    if [ "${OFFLINE}" == "yes" ]; then
+        set -x
+        log "Setting up for offline use"
+        local resolvconf=${mnt}/etc/resolv.conf
+        sudo mv ${resolvconf} ${resolvconf}.old
+        sudo cp /etc/resolv.conf ${resolvconf}
+        for installer_package in "${INSTALLER_DEPS[@]}"; do
+            sudo chroot ${mnt} apt-get install $installer_package
+        done
+        sudo rm ${resolvconf}
+        sudo mv ${resolvconf}.old ${resolvconf}
+        set +x
+    fi
+
     if [ "${bootloader}" == "syslinux" ]; then
         sudo mkdir -p ${mnt}/boot/extlinux &&
         sudo extlinux --install ${mnt}/boot/extlinux &&
@@ -479,8 +507,8 @@ parse_args() {
     # args:
     [ $# -lt 1 ] && { usage; exit 0; }
 
-    OPTS_LONG="arch:,bootloader:,download:,help,release:,stream:,verbose,version:"
-    OPTS="a:b:d:hr:s:vV:"
+    OPTS_LONG="arch:,bootloader:,download:,help,offline,release:,stream:,verbose,version:"
+    OPTS="a:b:d:hor:s:vV:"
     ARGS=`getopt --name "$PROG" --long $OPTS_LONG --options $OPTS -- "$@"`
     if [ $? -ne 0 ]; then
         echo "$PROG: usage error (use -h for help)" >&2
@@ -491,6 +519,7 @@ parse_args() {
     ARCH="amd64"
     BOOTLOADER="syslinux"
     DLDIR=~/download
+    OFFLINE="no"
     RELEASE="wily"
     STREAM="daily"
     VERBOSE="no"
@@ -501,6 +530,7 @@ parse_args() {
             -b | --bootloader)  BOOTLOADER="$2"; shift;;
             -d | --download)    DLDIR="$2"; shift;;
             -h | --help)        usage; exit 0;;
+            -o | --offline)     OFFLINE="yes";;
             -r | --release)     RELEASE="$2"; shift;;
             -s | --stream)      STREAM="$2"; shift;;
             -V | --version)     VERSION="$2"; shift;;
@@ -538,11 +568,11 @@ main() {
     CACHEDIR=${_RETVAL}
     log "CACHEDIR=$CACHEDIR"
 
-    generate_seed ${DLDIR} $CACHEDIR || {
+    generate_seed ${DLDIR} $CACHEDIR $OFFLINE || {
         return 1;
     }
 
-    generate_img ${DLDIR} $CACHEDIR $BOOTLOADER || {
+    generate_img ${DLDIR} $CACHEDIR $BOOTLOADER $OFFLINE || {
         return 1;
     }
     INSTALLIMG=${_RETVAL}