diff --git a/bin/compose b/bin/compose
index 1c9b3ec..946e442 100755
--- a/bin/compose
+++ b/bin/compose
@@ -32,9 +32,9 @@
       }
 #:-
 
-
 include pretty
 include parse
+include charm
 
 depends shyaml docker
 
@@ -930,7 +930,7 @@ service_base_docker_image() {
             echo "$service_def" >&2
             return 1
         fi
-        service_dockerfile="$CHARM_STORE/${service_build}/Dockerfile"
+        service_dockerfile="$(charm.get_dir "${service_build%%/*}")"/"${service_build#*/}"/Dockerfile
         if ! [ -e "$service_dockerfile" ]; then
             err "No Dockerfile found in '$service_dockerfile' location."
             return 1
@@ -953,7 +953,7 @@ get_charm_relation_def () {
         cat "$cache_file"
         return 0
     fi
-    metadata="$(get_charm_metadata "$charm")" || return 1
+    metadata="$(charm.metadata "$charm")" || return 1
     relation_def="$(echo "$metadata" | shyaml get-value "provides.${relation_name}" 2>/dev/null)"
     echo "$relation_def" | tee "$cache_file"
 }
@@ -1081,14 +1081,11 @@ run_service_hook () {
             fi
 
             charm=$(get_service_charm "$subservice") || return 1
-            TARGET_SCRIPT="$CHARM_STORE/$charm/hooks/$action"
-            [ -e "$TARGET_SCRIPT" ] || continue
+            charm.has_hook "$charm" "$action" >/dev/null || continue
 
             PROJECT_NAME=$(get_default_project_name) || return 1
             Wrap -d "$YELLOW$action$NORMAL hook of charm $DARKYELLOW$charm$NORMAL" <<EOF || return 1
 
-            cd "$CHARM_STORE/$charm"
-
             export SERVICE_NAME=$subservice
             export IMAGE_NAME=$(echo "${PROJECT_NAME}" | tr -d "_-")_\${SERVICE_NAME}
             export CONTAINER_NAME=\${IMAGE_NAME}_1
@@ -1098,7 +1095,7 @@ run_service_hook () {
             export SERVICE_DATASTORE="$DATASTORE/$charm"
             export SERVICE_CONFIGSTORE="$CONFIGSTORE/$charm"
 
-            "$TARGET_SCRIPT"
+            charm.run_hook "$charm" "$action"
 
 EOF
             loaded[$subservice]=1
@@ -1289,28 +1286,19 @@ _run_service_relation () {
 
     charm=$(get_service_charm "$service") || return 1
     target_charm=$(get_service_charm "$target_service") || return 1
-    base_script_name=$(echo "$relation_name" | tr "-" "_" )-relation-joined
-    script_name="hooks/${base_script_name}"
 
-    [ ! -e "$CHARM_STORE/$target_charm/$script_name" -a ! -e "$CHARM_STORE/$charm/$script_name" ] &&
-        return 0
+    base_script_name=$(charm.has_relation_hook "$charm" "$relation_name" relation-joined) || true
+    target_script_name=$(charm.has_relation_hook "$target_charm" "$relation_name" relation-joined) || true
+    [ "$base_script_name" -o "$target_script_name" ] || return 0
 
     relation_dir=$(get_relation_data_dir "$charm" "$target_charm" "$relation_name") || return 1
     RELATION_DATA_FILE=$(get_relation_data_file "$charm" "$target_charm" "$relation_name" "$relation_config") || return 1
-    RELATION_BASE_COMPOSE_DEF=$(get_compose_service_def "$service") || return 1
-    RELATION_TARGET_COMPOSE_DEF=$(get_compose_service_def "$target_service") || return 1
-    export BASE_SERVICE_NAME=$service
-    export TARGET_SERVICE_NAME=$target_service
     export BASE_CHARM_NAME=$charm
     export TARGET_CHARM_NAME=$target_charm
-    PROJECT_NAME=$(get_default_project_name) || return 1
-    MASTER_BASE_CHARM_NAME=$(get_top_master_charm_for_service "$service") || return 1
-    MASTER_TARGET_CHARM_NAME=$(get_top_master_charm_for_service "$target_service") || return 1
-    export RELATION_DATA_FILE RELATION_BASE_COMPOSE_DEF RELATION_TARGET_COMPOSE_DEF
-    export MASTER_BASE_CHARM_NAME MASTER_TARGET_CHARM_NAME PROJECT_NAME
+    export RELATION_DATA_FILE
     target_errlvl=0
-    if ! [ -e "$CHARM_STORE/$target_charm/$script_name" ]; then
-        verb "No relation script '$script_name' in $DARKYELLOW$target_charm$NORMAL."
+    if [ -z "$target_script_name" ]; then
+        verb "No relation script $DARKBLUE$relation_name$NORMAL in target $DARKYELLOW$target_charm$NORMAL."
     else
         verb "Running ${DARKBLUE}$relation_name${NORMAL} relation-joined script" \
              "for target charm $DARKYELLOW$target_charm$NORMAL"
@@ -1319,12 +1307,11 @@ _run_service_relation () {
         export DOCKER_BASE_IMAGE RELATION_CONFIG RELATION_DATA
         {
             (
-                cd "$CHARM_STORE/$target_charm"
                 SERVICE_NAME=$target_service
                 SERVICE_DATASTORE="$DATASTORE/$target_charm"
                 SERVICE_CONFIGSTORE="$CONFIGSTORE/$target_charm"
                 export SERVICE_NAME DOCKER_BASE_IMAGE SERVICE_DATASTORE SERVICE_CONFIGSTORE
-                "$script_name"
+                charm.run_relation_hook "$target_charm" "$relation_name" relation-joined
                 echo "$?" > "$relation_dir/target_errlvl"
             ) | logstdout "$DARKYELLOW$target_charm$NORMAL/$DARKBLUE$relation_name$NORMAL (joined) ${GREEN}@${NORMAL}"
         } 3>&1 1>&2 2>&3 | logstderr "$DARKYELLOW$target_charm$NORMAL/$DARKBLUE$relation_name$NORMAL (joined) ${RED}@${NORMAL}" 3>&1 1>&2 2>&3
@@ -1343,7 +1330,7 @@ _run_service_relation () {
 
     if [ "$target_errlvl" == 0 ]; then
         errlvl=0
-        if [ -e "$CHARM_STORE/$charm/$script_name" ]; then
+        if [ "$base_script_name" ]; then
             verb "Running ${DARKBLUE}$relation_name${NORMAL} relation-joined script" \
                  "for charm $DARKYELLOW$charm$NORMAL"
             RELATION_CONFIG="$relation_dir/config_providee"
@@ -1352,12 +1339,11 @@ _run_service_relation () {
             export DOCKER_BASE_IMAGE RELATION_CONFIG RELATION_DATA
             {
                 (
-                    cd "$CHARM_STORE/$charm"
                     SERVICE_NAME=$service
                     SERVICE_DATASTORE="$DATASTORE/$charm"
                     SERVICE_CONFIGSTORE="$CONFIGSTORE/$charm"
                     export SERVICE_NAME DOCKER_BASE_IMAGE SERVICE_DATASTORE SERVICE_CONFIGSTORE
-                    "$script_name"
+                    charm.run_relation_hook "$charm" "$relation_name" relation-joined
                     echo "$?" > "$relation_dir/errlvl"
                 ) | logstdout "$DARKYELLOW$charm$NORMAL/$DARKBLUE$relation_name$NORMAL (joined) ${GREEN}@${NORMAL}"
             } 3>&1 1>&2 2>&3 | logstderr "$DARKYELLOW$charm$NORMAL/$DARKBLUE$relation_name$NORMAL (joined) ${RED}@$NORMAL" 3>&1 1>&2 2>&3
@@ -1463,14 +1449,32 @@ export -f get_compose_relations
 
 run_service_relations () {
     local services="$1" loaded
+
+    PROJECT_NAME=$(get_default_project_name) || return 1
+
+    export PROJECT_NAME
+
     declare -A loaded
     for service in $(get_ordered_service_dependencies $services); do
+
         # debug "Upping dep's relations of ${DARKYELLOW}$service${NORMAL}:"
         for subservice in $(get_service_deps "$service") "$service"; do
             [ "${loaded[$subservice]}" ] && continue
+
+            export BASE_SERVICE_NAME=$service
+            MASTER_BASE_CHARM_NAME=$(get_top_master_charm_for_service "$subservice") || return 1
+            RELATION_BASE_COMPOSE_DEF=$(get_compose_service_def "$subservice") || return 1
+            export RELATION_BASE_COMPOSE_DEF MASTER_BASE_CHARM_NAME
+
             # debug "  Relations of ${DARKYELLOW}$subservice${NORMAL}:"
             while read-0 relation_name target_service relation_config tech_dep; do
                 export relation_config
+
+                export TARGET_SERVICE_NAME=$target_service
+                MASTER_TARGET_CHARM_NAME=$(get_top_master_charm_for_service "$target_service") || return 1
+                RELATION_TARGET_COMPOSE_DEF=$(get_compose_service_def "$target_service") || return 1
+                export MASTER_TARGET_CHARM_NAME RELATION_TARGET_COMPOSE_DEF
+
                 Wrap -d "Building $DARKYELLOW$subservice$NORMAL --$DARKBLUE$relation_name$NORMAL--> $DARKYELLOW$target_service$NORMAL" <<EOF || return 1
 _run_service_relation "$relation_name" "$subservice" "$target_service" "\$relation_config"
 EOF
@@ -1483,10 +1487,10 @@ export -f run_service_relations
 
 
 _run_service_action_direct() {
-    local service="$1" action="$2" charm script _dummy
+    local service="$1" action="$2" charm  _dummy
     shift; shift
 
-    read-0 charm script || true  ## against 'set -e' that could be setup in parent scripts
+    read-0 charm  || true  ## against 'set -e' that could be setup in parent scripts
 
     if read-0 _dummy || [ "$_dummy" ]; then
         print_syntax_error "$FUNCNAME: too many arguments in action descriptor"
@@ -1499,9 +1503,8 @@ _run_service_action_direct() {
     {
         (
             set +e  ## Prevents unwanted leaks from parent shell
-            cd "$CHARM_STORE/$charm"
             export COMPOSE_CONFIG=$(cat "$compose_file")
-            export METADATA_CONFIG=$(cat "$CHARM_STORE/$charm/metadata.yml")
+            export METADATA_CONFIG=$(charm.metadata "$charm")
             export SERVICE_NAME=$service
             export ACTION_NAME=$action
             export CONTAINER_NAME=$(get_top_master_charm_for_service "$service")
@@ -1509,7 +1512,7 @@ _run_service_action_direct() {
             export SERVICE_DATASTORE="$DATASTORE/$service"
             export SERVICE_CONFIGSTORE="$CONFIGSTORE/$service"
             exname="$exname $ACTION_NAME $SERVICE_NAME" \
-                    stdbuf -oL -eL "$script" "$@"
+                    stdbuf -oL -eL charm.run_direct_action "$charm" "$action" "$@"
             echo "$?" > "$action_errlvl_file"
         ) | logstdout "$DARKYELLOW$charm$NORMAL/${DARKCYAN}$action${NORMAL} ${GREEN}@${NORMAL}"
     } 3>&1 1>&2 2>&3 | logstderr "$DARKYELLOW$charm$NORMAL/${DARKCYAN}$action${NORMAL} ${RED}@$NORMAL" 3>&1 1>&2 2>&3
@@ -1523,10 +1526,10 @@ _run_service_action_direct() {
 export -f _run_service_action_direct
 
 _run_service_action_relation() {
-    local service="$1" action="$2" charm target_charm relation_name target_script relation_config _dummy
+    local service="$1" action="$2" charm target_charm relation_name relation_config _dummy
     shift; shift
 
-    read-0 charm target_charm relation_name target_script relation_config || true
+    read-0 charm target_charm relation_name relation_config || true
 
     if read-0 _dummy || [ "$_dummy" ]; then
         print_syntax_error "$FUNCNAME: too many arguments in action descriptor"
@@ -1541,8 +1544,7 @@ _run_service_action_relation() {
     {
         (
             set +e  ## Prevents unwanted leaks from parent shell
-            cd "$CHARM_STORE/$charm"
-            export METADATA_CONFIG=$(cat "$CHARM_STORE/$charm/metadata.yml")
+            export METADATA_CONFIG=$(charm.metadata "$charm")
             export SERVICE_NAME=$service
             export RELATION_TARGET_CHARM="$target_charm"
             export RELATION_BASE_CHARM="$charm"
@@ -1552,7 +1554,7 @@ _run_service_action_relation() {
             export SERVICE_DATASTORE="$DATASTORE/$service"
             export SERVICE_CONFIGSTORE="$CONFIGSTORE/$service"
             exname="$exname $ACTION_NAME $SERVICE_NAME" \
-                    stdbuf -oL -eL "$target_script" "$@"
+                    stdbuf -oL -eL charm.run_relation_action "$charm" "$relation_name" "$action" "$@"
             echo "$?" > "$action_errlvl_file"
         ) | logstdout "$DARKYELLOW$charm$NORMAL/${DARKCYAN}$action${NORMAL} ${GREEN}@${NORMAL}"
     } 3>&1 1>&2 2>&3 | logstderr "$DARKYELLOW$charm$NORMAL/${DARKCYAN}$action${NORMAL} ${RED}@$NORMAL" 3>&1 1>&2 2>&3
@@ -1614,7 +1616,7 @@ export -f get_relation_data_file
 
 has_service_action () {
     local service="$1" action="$2" cache_file="$state_tmpdir/$FUNCNAME.cache.$1" \
-          target_script charm target_charm
+          charm target_charm
     if [ -e "$cache_file" ]; then
         # debug "$FUNCNAME: cache hit ($*)"
         cat "$cache_file"
@@ -1625,17 +1627,15 @@ has_service_action () {
 
     ## Action directly provided ?
 
-    target_script="$CHARM_STORE/$charm/actions/$action"
-    if [ -x "$target_script" ]; then
-        echo -en "direct\0$charm\0$target_script" | tee "$cache_file"
+    if charm.has_direct_action "$charm" "$action"; then
+        echo -en "direct\0$charm" | tee "$cache_file"
         return 0
     fi
     ## Action provided by relation ?
     while read-0 relation_name target_service relation_config tech_dep; do
         target_charm=$(get_service_charm "$target_service") || return 1
-        target_script="$CHARM_STORE/$target_charm/actions/relations/$relation_name/$action"
-        if [ -x "$target_script" ]; then
-            echo -en "relation\0$charm\0$target_charm\0$relation_name\0$target_script\0$relation_config" | tee "$cache_file"
+        if charm.has_relation_action "$target_charm" "$relation_name" "$action"; then
+            echo -en "relation\0$charm\0$target_charm\0$relation_name\0$relation_config" | tee "$cache_file"
             return 0
         fi
     done < <(get_compose_relations "$service")
@@ -1656,7 +1656,7 @@ run_service_action () {
     {
         if ! read-0 action_type; then
             info "Service $DARKYELLOW$service$NORMAL does not have any action $DARKCYAN$action$NORMAL defined."
-            info "  Add an executable script to '$CHARM_STORE/$charm/actions/$action' to implement action."
+            info "  Add an executable script to 'actions/$action' to implement action."
             return 1
         fi
 
@@ -1776,7 +1776,10 @@ get_master_charm_for_service() {
     fi
 
     charm=$(get_service_charm "$service") || return 1
-    metadata=$(get_charm_metadata "$charm") || return 1
+    metadata=$(charm.metadata "$charm") || {
+        err "Failed to access metadata of charm $DARKYELLOW$charm$NORMAL"
+        return 1
+    }
     result=$(_get_master_charm_for_service_cached "$service" "$charm" "$metadata") || return 1
     echo "$result" | tee "$cache_file"
 }
@@ -1805,20 +1808,6 @@ get_top_master_charm_for_service() {
 export -f get_top_master_charm_for_service
 
 
-get_charm_metadata() {
-    local charm="$1" metadata_file
-    metadata_file="$CHARM_STORE/$charm/metadata.yml"
-    if ! [ -e "$metadata_file" ]; then
-        return 0  ## No metadata file is as if metadata was empty
-    fi
-
-    if ! [ -d "$CHARM_STORE/$charm" ]; then
-        die "No charm $charm was found in charm store."
-    fi
-    cat "$metadata_file"
-}
-export -f get_charm_metadata
-
 ##
 ## The result is a mixin that is not always a complete valid
 ## docker-compose entry (thinking of subordinates). The result
@@ -1850,7 +1839,11 @@ _get_docker_compose_mixin_from_metadata_cached() {
                 fi
             done < <(echo "$metadata" | shyaml get-values-0 "host-resources" 2>/dev/null)
             while read-0 resource; do
-                echo "  - $CHARM_STORE/$charm/resources$resource:$resource:rw"
+                dest="$(charm.get_dir "$charm")/resources$resource"
+                if ! [ -e "$dest" ]; then
+                    die "charm-resource: '$resource' does not exist (file: '$dest')."
+                fi
+                echo "  - $dest:$resource:rw"
             done < <(echo "$metadata" | shyaml get-values-0 "charm-resources" 2>/dev/null)
                ) || return 1
         if [ "$volumes" ]; then
@@ -1875,7 +1868,7 @@ _get_docker_compose_mixin_from_metadata_cached() {
             return 1
         fi
         image_or_build_statement="image: $image"
-    elif [ -d "$CHARM_STORE/$charm/build" ]; then
+    elif [ -d "$(charm.get_dir "$charm")/build" ]; then
         if [ "$subordinate" ]; then
             err "Subordinate charm can not have a 'build' sub directory."
             return 1
@@ -1898,7 +1891,7 @@ get_docker_compose_mixin_from_metadata() {
         return 0
     fi
 
-    metadata="$(get_charm_metadata "$charm")" || return 1
+    metadata="$(charm.metadata "$charm")" || return 1
     mixin=$(_get_docker_compose_mixin_from_metadata_cached "$charm" "$metadata") || return 1
     echo "$mixin" | tee "$cache_file"
 }
@@ -1930,7 +1923,7 @@ export -f get_default_project_name
 
 
 launch_docker_compose() {
-
+    local charm
     docker_compose_tmpdir=$(mktemp -d -t tmp.XXXXXXXXXX)
     #debug "Creating temporary docker-compose directory in '$docker_compose_tmpdir'."
 #     trap_add EXIT "debug \"Removing temporary docker-compose directory in $docker_compose_tmpdir.\";\
@@ -1951,11 +1944,15 @@ launch_docker_compose() {
     fi
 
     if [ -z "$(echo $(cat "$docker_compose_dir/docker-compose.yml"))" ]; then
-        die "Generated 'docker-compose.yml' is unexpectedly empty. Check your charm availability in '$CHARM_STORE'."
+        die "Generated 'docker-compose.yml' is unexpectedly empty."
     fi
 
     ## XXXvlab: could be more specific and only link the needed charms
-    ln -sf "$CHARM_STORE/"* "$docker_compose_dir/"
+    for charm in $(shyaml keys < "$docker_compose_dir/docker-compose.yml"); do
+        if charm.exists "$charm"; then
+            ln -sf "$(charm.get_dir "$charm")" "$docker_compose_dir/$charm" || exit 1
+        fi
+    done
     mkdir "$docker_compose_dir/.data"
 
     {
@@ -2234,7 +2231,6 @@ done
 ## Actual code
 ##
 
-export CHARM_STORE=${CHARM_STORE:-/srv/charm-store}
 export DOCKER_DATASTORE=${DOCKER_DATASTORE:-/srv/docker-datastore}
 
 COMPOSE_YML_FILE=$(get_compose_yml_location) || exit 1
@@ -2252,20 +2248,7 @@ if [ "$?" != 0 ]; then
     exit 1
 fi
 
-
-if ! [ -d "$CHARM_STORE" ]; then
-    err "Charm store path $YELLOW$CHARM_STORE$NORMAL does not exists. "
-    err "Please check your $YELLOW\$CHARM_STORE$NORMAL variable value."
-    exit 1
-fi
-
-
-if [ -z "$(cd "$CHARM_STORE"; ls)" ]; then
-    err "no available charms in charm store $YELLOW$CHARM_STORE$NORMAL. Either:"
-    err "  - check $YELLOW\$CHARM_STORE$NORMAL variable value"
-    err "  - download charms in $CHARM_STORE"
-    print_error "Charm store is empty. Cannot continue."
-fi
+charm.sanity_checks || die "Sanity checks about charm-store failed. Please correct."
 
 ##
 ## Get services in command line.