'Playing' with bscs.benbrown/understanding-bscs

2 files changed, 34 insertions, 48 deletions

diff --git a/baserock-system-config-sync/baserock-system-config-sync b/baserock-system-config-sync/baserock-system-config-sync
index cb5984d..09b4198 100755
--- a/baserock-system-config-sync/baserock-system-config-sync
+++ b/baserock-system-config-sync/baserock-system-config-sync
@@ -62,11 +62,6 @@ check_same_type() {
 
 merge() {
     local vp_dir="$1" # version being processed
-    local v1_dir="$2" # factory version
-    local vu_dir="$3" # user modified version
-    local v2_dir="$4" # unmodified new deployed version
-    local vt_dir="$5" # target version where the result of the
-                      # merge should be placed
 
     # use `find "$vp_dir/"*` instead of `find "$vp_dir"` because
     # the last one also gives $vp_dir in the list of directories
@@ -76,10 +71,10 @@ merge() {
         local stripped_filename=${f#$vp_dir/}
 
         local vp="$vp_dir/$stripped_filename"
-        local v1="$v1_dir/$stripped_filename"
-        local vu="$vu_dir/$stripped_filename"
-        local v2="$v2_dir/$stripped_filename"
-        local vt="$vt_dir/$stripped_filename"
+        v1="$v1_dir/$stripped_filename"
+        vu="$vu_dir/$stripped_filename"
+        v2="$v2_dir/$stripped_filename"
+        vt="$vt_dir/$stripped_filename"
 
         if [ ! -e "$vt" ]; then
             if [ -e "$v1" -a -e "$vu" ]; then
@@ -104,7 +99,7 @@ merge() {
                     cp -a "$v1" "$vt"
                 fi
             elif [ -f "$vp" ]; then
-                merge_regular_file "$v1" "$vu" "$v2" "$vt"
+                merge_regular_file
             else
                 die "ERROR: unexpected error"
             fi
@@ -114,10 +109,6 @@ merge() {
 
 
 merge_regular_file() {
-    local v1="$1"
-    local vu="$2"
-    local v2="$3"
-    local vt="$4"
     # Reference table for merging a regular file
     #
     # V1      Vuser       V2          action
@@ -167,48 +158,44 @@ merge_regular_file() {
 }
 
 
-if [ "$#" = 0 ]; then
+if [ "$#" != 2 ]; then
     usage "$0"
 fi
 
+tempdir=$(mktemp -d)
+version_label="$2"
 
 if [ "$1" = "merge" ]; then
-    if [ "$#" != 2 ]; then
-        usage "$0"
+    "$mounting_script" "$tempdir"
+    if [ ! -d "$tempdir/systems/$version_label" ]; then
+        "$unmount" "$tempdir"
+        die "Error: version not found - '$version_label'"
     fi
-    new_version="$2"
-    mounting_point=$(mktemp -d)
-    "$mounting_script" "$mounting_point"
-    if [ ! -d "$mounting_point/systems/$new_version" ]; then
-        "$unmount" "$mounting_point"
-        die "Error: version not found - '$new_version'"
-    fi
-    v1_dir="$mounting_point/systems/default/orig/etc"
-    vu_dir="$mounting_point/systems/default/run/etc"
-    v2_dir="$mounting_point/systems/$new_version/run/etc"
-    vt_dir="$mounting_point/systems/$new_version/run/etc.new"
-    mkdir "$vt_dir"
-    trap 'rm -rvf "$vt_dir"; "$unmount" "$mounting_point"' EXIT
+    factory_etc="$tempdir/systems/default/orig/etc" # factory version
+    user_etc="$tempdir/systems/default/run/etc" # user modified version
+    new_etc="$tempdir/systems/$version_label/run/etc" # newly deployed version
+    merge_etc="$tempdir/systems/$version_label/run/etc.new" # target version
+
+    mkdir "$merge_etc"
+    trap 'rm -rvf "$merge_etc"; "$unmount" "$tempdir"' EXIT INT TERM
     # For every pathname in V1, Vuser, or V2
-    merge "$v1_dir" "$v1_dir" "$vu_dir" "$v2_dir" "$vt_dir"
-    merge "$vu_dir" "$v1_dir" "$vu_dir" "$v2_dir" "$vt_dir"
-    merge "$v2_dir" "$v1_dir" "$vu_dir" "$v2_dir" "$vt_dir"
+    merge "$factory_etc"
+    merge "$user_etc"
+    merge "$new_etc"
 
-    rm -rf "$v2_dir"
-    mv "$vt_dir" "$v2_dir"
+    rm -rf "$new_etc"
+    mv "$merge_etc" "$new_etc"
 elif [ "$1" = "sync" ]; then
-    canonical_version="$2"
-    mounting_point=$(mktemp -d)
-    "$mounting_script" "$mounting_point"
-    trap '"$unmount" "$mounting_point"' EXIT
-    if [ ! -d "$mounting_point/systems/$canonical_version" ]; then
-        die "Error: version not found - '$canonical_version'"
+    "$mounting_script" "$tempdir"
+    trap '"$unmount" "$tempdir"' EXIT INT TERM
+    if [ ! -d "$tempdir/systems/$version_label" ]; then
+        die "Error: version not found - '$version_label'"
     fi
-    for version_dir in "$mounting_point/systems/"*; do
+    for version_dir in "$tempdir/systems/"*; do
         version="$(basename "$version_dir")"
         if [ -d "$version_dir" -a ! -h "$version_dir" \
-                -a $version != $canonical_version ]; then
-            cp -a "$mounting_point/systems/$canonical_version/run/etc" \
+                -a $version != $version_label ]; then
+            cp -a "$tempdir/systems/$version_label/run/etc" \
                 "$version_dir/run/etc.new"
             mv "$version_dir/run/etc" "$version_dir/run/etc.old"
             mv "$version_dir/run/etc.new" "$version_dir/run/etc"
@@ -218,4 +205,3 @@ elif [ "$1" = "sync" ]; then
 else
     usage "$0"
 fi
-
diff --git a/baserock-system-config-sync/mount-system-versions-dir b/baserock-system-config-sync/mount-system-versions-dir
index 6028ea4..b41f3a6 100755
--- a/baserock-system-config-sync/mount-system-versions-dir
+++ b/baserock-system-config-sync/mount-system-versions-dir
@@ -30,11 +30,11 @@ if [ "$#" != 1 ]; then
 fi
 
 
-mouting_point="$1"
+mounting_point="$1"
 
 disk=$(awk '{ if ($1 != "rootfs" &&  $2 == "/") print $1 }' /proc/mounts)
 
-mkdir -p "$mouting_point"
+mkdir -p "$mounting_point"
 
-mount "$disk" "$mouting_point"
+mount "$disk" "$mounting_point"