new: ``charm`` and ``service`` are cleanly separated concepts now

``charm`` is the general recipes. ``service`` is a practical
functionality that will (if not subordinated) spawn a docker container.
In your compose file, you define services that will apply some general
rules borrowed from ``charm``s. Different services can link to the same
charm.

bin/compose

@@ -58,7 +58,8 @@ run without launching ${WHITE}docker-compose${NORMAL}.
 In compose message, color coding is enforced as such:
  - ${DARKCYAN}action$NORMAL,
  - ${DARKBLUE}relation$NORMAL,
- - ${DARKYELLOW}charm${NORMAL}/${DARKYELLOW}service${NORMAL},
+ - ${DARKPINK}charm${NORMAL},
+ - ${DARKYELLOW}service${NORMAL},
  - ${WHITE}option-name${NORMAL}/${WHITE}command-name${NORMAL}/${WHITE}Section-Title${NORMAL}
 
 $WHITE$exname$NORMAL reads '/etc/compose.conf' for global variables, and
@@ -99,7 +100,7 @@ clean_cache() {
 
 trap_add "EXIT" clean_cache
 
-usage="$exname CHARM"'
+usage="$exname SERVICE"'
 
 Deploy and manage a swarm of containers to provide services based on
 a ``compose.yml`` definition and charms from a ``charm-store``.
@@ -273,22 +274,22 @@ docker_has_image() {
 export -f docker_has_image
 
 cmd_on_base_image() {
-    local charm="$1" base_image
+    local service="$1" base_image
     shift
-    base_image=$(service_base_docker_image "$charm") || return 1
+    base_image=$(service_base_docker_image "$service") || return 1
     docker run -i --entrypoint /bin/bash "$base_image" -c "$*"
 }
 export -f cmd_on_base_image
 
 cached_cmd_on_base_image() {
-    local charm="$1" cache_file="$state_tmpdir/$FUNCNAME.cache.$(echo "$*" | md5_compat)"
+    local service="$1" cache_file="$state_tmpdir/$FUNCNAME.cache.$(echo "$*" | md5_compat)"
     shift
     if [ -e "$cache_file" ]; then
         # debug "$FUNCNAME: cache hit ($*)"
         quick_cat_stdin < "$cache_file"
         return 0
     fi
-    result=$(cmd_on_base_image "$charm" "$@") || return 1
+    result=$(cmd_on_base_image "$service" "$@") || return 1
     echo "$result" | tee "$cache_file"
 }
 export -f cached_cmd_on_base_image
@@ -696,7 +697,8 @@ export -f get_running_containers_for_service
 
 get_docker_compose_links() {
     local service="$1" cache_file="$state_tmpdir/$FUNCNAME.cache.$1" \
-          links charm charm_part master_charm
+          deps master_service master_target_service _relation_name \
+          target_service _relation_config tech_dep
     if [ -z "$service" ]; then
         print_syntax_error "$FUNCNAME: Please specify a service as first argument."
         return 1
@@ -708,16 +710,16 @@ get_docker_compose_links() {
         return 0
     fi
 
-    master_charm=$(get_top_master_charm_for_service "$service") || return 1
+    master_service=$(get_top_master_service_for_service "$service") || return 1
 
     deps=()
-    while read-0 relation_name target_service relation_config tech_dep; do
-        master_target_charm="$(get_top_master_charm_for_service "$target_service")"
-        [ "$master_charm" == "$master_target_charm" ] && continue
+    while read-0 _relation_name target_service _relation_config tech_dep; do
+        master_target_service="$(get_top_master_service_for_service "$target_service")"
+        [ "$master_service" == "$master_target_service" ] && continue
         if [ "$tech_dep" == "reversed" ]; then
-            deps+=("$(echo -en "$master_target_charm:\n  links:\n    - $master_charm")")
+            deps+=("$(echo -en "$master_target_service:\n  links:\n    - $master_service")")
         elif [ "$tech_dep" == "True" ]; then
-            deps+=("$(echo -en "$master_charm:\n  links:\n    - $master_target_charm")")
+            deps+=("$(echo -en "$master_service:\n  links:\n    - $master_target_service")")
         fi
     done < <(get_compose_relations "$service") || return 1
 
@@ -731,7 +733,7 @@ get_docker_compose_links() {
 
 _get_docker_compose_opts() {
     local service="$1" cache_file="$state_tmpdir/$FUNCNAME.cache.$1" \
-          links charm charm_part master_charm
+          compose_def master_service docker_compose_opts
     if [ -z "$service" ]; then
         print_syntax_error "$FUNCNAME: Please specify a service as first argument."
         return 1
@@ -744,11 +746,11 @@ _get_docker_compose_opts() {
     fi
 
     compose_def="$(get_compose_service_def "$service")" || return 1
-    master_charm="$(get_top_master_charm_for_service "$service")"
+    master_service="$(get_top_master_service_for_service "$service")"
     docker_compose_opts=$(echo "$compose_def" | shyaml get-value "docker-compose" 2>/dev/null)
 
     if [ "$docker_compose_opts" ]; then
-        yaml_key_val_str "$master_charm" "$docker_compose_opts"
+        yaml_key_val_str "$master_service" "$docker_compose_opts"
     fi | tee "$cache_file"
     if [ "${PIPESTATUS[0]}" != 0 ]; then
         rm "$cache_file"
@@ -762,7 +764,9 @@ _get_docker_compose_opts() {
 ## Some metadata.yml (of subordinates) will indeed modify other
 ## services than themselves.
 _get_docker_compose_service_mixin() {
-    local service="$1" cache_file="$state_tmpdir/$FUNCNAME.cache.$1" links charm charm_part
+    local service="$1" cache_file="$state_tmpdir/$FUNCNAME.cache.$1" \
+          links_yaml base_mixin links_yaml docker_compose_options \
+          charm charm_part
     if [ -z "$service" ]; then
         print_syntax_error "$FUNCNAME: Please specify a service as first argument."
         return 1
@@ -774,17 +778,17 @@ _get_docker_compose_service_mixin() {
         return 0
     fi
 
-    master_charm=$(get_top_master_charm_for_service "$service") || {
-        err "Failed to get top master charm for service $DARKYELLOW$service$NORMAL"
+    master_service=$(get_top_master_service_for_service "$service") || {
+        err "Failed to get top master service for service $DARKYELLOW$service$NORMAL"
         return 1
     }
 
     ## The compose part
 
-    base_mixin="$master_charm:
+    base_mixin="$master_service:
   labels:
    - \"compose.service=$service\"
-   - \"compose.master-charm=${master_charm}\"
+   - \"compose.master-service=${master_service}\"
    - \"compose.project=$(get_default_project_name)\""
     links_yaml=$(get_docker_compose_links "$service") || return 1
     docker_compose_options=$(_get_docker_compose_opts "$service") || return 1
@@ -793,11 +797,11 @@ _get_docker_compose_service_mixin() {
 
     #debug "Get charm name from service name $DARKYELLOW$service$NORMAL."
     charm=$(get_service_charm "$service") || return 1
-    charm_part=$(get_docker_compose_mixin_from_metadata "$charm") || return 1
+    charm_part=$(get_docker_compose_mixin_from_metadata "$service" "$charm") || return 1
 
     ## Merge results
     if [ "$charm_part" ]; then
-        charm_yaml="$(yaml_key_val_str "$master_charm" "$charm_part")" || return 1
+        charm_yaml="$(yaml_key_val_str "$master_service" "$charm_part")" || return 1
         merge_yaml_str "$base_mixin" "$links_yaml" "$charm_yaml" "$docker_compose_options" || return 1
     else
         merge_yaml_str "$base_mixin" "$links_yaml" "$docker_compose_options" || return 1
@@ -831,7 +835,7 @@ get_docker_compose () {
 
     declare -A entries
     start_compilation=$SECONDS
-    debug "Compiling 'docker-compose.yml' base for $DARKYELLOW$@$NORMAL..."
+    debug "Compiling 'docker-compose.yml' base for ${DARKYELLOW}$*$NORMAL..."
     for target_service in "$@"; do
         start=$SECONDS
         services=$(get_ordered_service_dependencies "$target_service") || {
@@ -933,7 +937,7 @@ _get_service_charm_cached () {
     fi
     charm=$(echo "$service_def" | shyaml get-value charm 2>/dev/null)
     if [ -z "$charm" ]; then
-        err "Missing charm in service $DARKYELLOW$service$NORMAL definition."
+        err "Missing ${WHITE}charm${NORMAL} value in service $DARKYELLOW$service$NORMAL definition."
         return 1
     fi
     echo "$charm" | tee "$cache_file"
@@ -973,18 +977,18 @@ export -f get_service_def
 ## Return the base docker image name of a service
 service_base_docker_image() {
     local service="$1" cache_file="$state_tmpdir/$FUNCNAME.cache.$1" \
-          master_charm charm service_image service_build service_dockerfile
+          master_service service_def service_image service_build service_dockerfile
     if [ -e "$cache_file" ]; then
         # debug "$FUNCNAME: cache hit ($*)"
         cat "$cache_file"
         return 0
     fi
-    master_charm="$(get_top_master_charm_for_service "$service")" || {
-        err "Could not compute base charm for service $DARKYELLOW$service$NORMAL."
+    master_service="$(get_top_master_service_for_service "$service")" || {
+        err "Could not compute master service for service $DARKYELLOW$service$NORMAL."
         return 1
     }
-    service_def="$(get_service_def "$master_charm")" || {
-        err "Could not get docker-compose service definition for $DARKYELLOW$master_charm$NORMAL."
+    service_def="$(get_service_def "$master_service")" || {
+        err "Could not get docker-compose service definition for $DARKYELLOW$master_service$NORMAL."
         return 1
     }
     service_image=$(echo "$service_def" | shyaml get-value image 2>/dev/null)
@@ -995,7 +999,7 @@ service_base_docker_image() {
             echo "$service_def" >&2
             return 1
         fi
-        service_dockerfile="$(charm.get_dir "${service_build%%/*}")"/"${service_build#*/}"/Dockerfile
+        service_dockerfile="${service_build}"/Dockerfile
         if ! [ -e "$service_dockerfile" ]; then
             err "No Dockerfile found in '$service_dockerfile' location."
             return 1
@@ -1027,7 +1031,7 @@ export -f get_charm_relation_def
 
 get_charm_tech_dep_orientation_for_relation() {
     local charm="$1" relation_name="$2" cache_file="$state_tmpdir/$FUNCNAME.cache.$1.$2" \
-          relation_def metadata value
+          relation_def value
     if [ -e "$cache_file" ]; then
         # debug "$FUNCNAME: cache hit ($*)"
         cat "$cache_file"
@@ -1150,17 +1154,19 @@ run_service_hook () {
             charm.has_hook "$charm" "$action" >/dev/null || continue
 
             PROJECT_NAME=$(get_default_project_name) || return 1
-            Wrap -d "$YELLOW$action$NORMAL hook of charm $DARKYELLOW$charm$NORMAL" <<EOF || return 1
+            export MASTER_BASE_SERVICE_NAME=$(get_top_master_service_for_service "$subservice") || return 1
+            export MASTER_BASE_CHARM_NAME=$(get_service_charm "$MASTER_BASE_SERVICE_NAME") || return 1
+
+            Wrap -d "running $YELLOW$action$NORMAL hook of $DARKYELLOW$subservice$NORMAL in charm $DARKPINK$charm$NORMAL" <<EOF || return 1
 
             export SERVICE_NAME=$subservice
-            export MASTER_BASE_CHARM_NAME=$(get_top_master_charm_for_service "$subservice") || return 1
-            export IMAGE_NAME=$(echo "${PROJECT_NAME}" | tr -d "_-")_\${MASTER_BASE_CHARM_NAME}
+            export IMAGE_NAME=$(echo "${PROJECT_NAME}" | tr -d "_-")_\${SERVICE_NAME}
             export CONTAINER_NAME=\${IMAGE_NAME}_1
             export CHARM_NAME="$charm"
             export PROJECT_NAME=$PROJECT_NAME
-            export DOCKER_BASE_IMAGE=$(service_base_docker_image "$charm")
-            export SERVICE_DATASTORE="$DATASTORE/$charm"
-            export SERVICE_CONFIGSTORE="$CONFIGSTORE/$charm"
+            export DOCKER_BASE_IMAGE=$(service_base_docker_image "$MASTER_BASE_SERVICE_NAME")
+            export SERVICE_DATASTORE="$DATASTORE/$subservice"
+            export SERVICE_CONFIGSTORE="$CONFIGSTORE/$subservice"
 
             charm.run_hook "$charm" "$action"
 
@@ -1366,34 +1372,37 @@ _run_service_relation () {
     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" "$relation_config") || return 1
+    relation_dir=$(get_relation_data_dir "$service" "$target_service" "$relation_name") || return 1
+    RELATION_DATA_FILE=$(get_relation_data_file "$service" "$target_service" "$relation_name" "$relation_config") || return 1
+    export BASE_SERVICE_NAME=$service
     export BASE_CHARM_NAME=$charm
     export BASE_CHARM_PATH=$(charm.get_dir "$charm")
+    export TARGET_SERVICE_NAME=$target_service
     export TARGET_CHARM_NAME=$target_charm
     export TARGET_CHARM_PATH=$(charm.get_dir "$target_charm")
     export RELATION_DATA_FILE
     target_errlvl=0
+
     if [ -z "$target_script_name" ]; then
-        verb "No relation script $DARKBLUE$relation_name$NORMAL in target $DARKYELLOW$target_charm$NORMAL."
+        verb "No relation script $DARKBLUE$relation_name$NORMAL in target $DARKPINK$target_charm$NORMAL."
     else
         verb "Running ${DARKBLUE}$relation_name${NORMAL} relation-joined script" \
-             "for target charm $DARKYELLOW$target_charm$NORMAL"
+             "for target $DARKYELLOW$target_service$NORMAL (charm $DARKPINK$target_charm$NORMAL)"
         RELATION_CONFIG="$relation_dir/config_provider"
         DOCKER_BASE_IMAGE=$(service_base_docker_image "$target_service") || return 1
         export DOCKER_BASE_IMAGE RELATION_CONFIG RELATION_DATA
         {
             (
                 SERVICE_NAME=$target_service
-                SERVICE_DATASTORE="$DATASTORE/$target_charm"
-                SERVICE_CONFIGSTORE="$CONFIGSTORE/$target_charm"
+                SERVICE_DATASTORE="$DATASTORE/$target_service"
+                SERVICE_CONFIGSTORE="$CONFIGSTORE/$target_service"
                 export SERVICE_NAME DOCKER_BASE_IMAGE SERVICE_DATASTORE SERVICE_CONFIGSTORE
                 charm.run_relation_hook "$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
+            ) | logstdout "$DARKYELLOW$target_service$NORMAL/$DARKBLUE$relation_name$NORMAL (joined) ${GREEN}@${NORMAL}"
+        } 3>&1 1>&2 2>&3 | logstderr "$DARKYELLOW$target_service$NORMAL/$DARKBLUE$relation_name$NORMAL (joined) ${RED}@${NORMAL}" 3>&1 1>&2 2>&3
         target_errlvl="$(cat "$relation_dir/target_errlvl")" || {
-            err "Relation script '$script_name' in $DARKYELLOW$target_charm$NORMAL" \
+            err "Relation script '$script_name' in $DARKPINK$target_charm$NORMAL" \
                 "failed before outputing an errorlevel."
             ((target_errlvl |= "1" ))
         }
@@ -1409,7 +1418,7 @@ _run_service_relation () {
         errlvl=0
         if [ "$base_script_name" ]; then
             verb "Running ${DARKBLUE}$relation_name${NORMAL} relation-joined script" \
-                 "for charm $DARKYELLOW$charm$NORMAL"
+                 "for $DARKYELLOW$service$NORMAL (charm $DARKPINK$charm$NORMAL)"
             RELATION_CONFIG="$relation_dir/config_providee"
             RELATION_DATA="$(cat "$RELATION_DATA_FILE")"
             DOCKER_BASE_IMAGE=$(service_base_docker_image "$service") || return 1
@@ -1417,15 +1426,15 @@ _run_service_relation () {
             {
                 (
                     SERVICE_NAME=$service
-                    SERVICE_DATASTORE="$DATASTORE/$charm"
-                    SERVICE_CONFIGSTORE="$CONFIGSTORE/$charm"
+                    SERVICE_DATASTORE="$DATASTORE/$service"
+                    SERVICE_CONFIGSTORE="$CONFIGSTORE/$service"
                     export SERVICE_NAME DOCKER_BASE_IMAGE SERVICE_DATASTORE SERVICE_CONFIGSTORE
                     charm.run_relation_hook "$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
+                ) | logstdout "$DARKYELLOW$service$NORMAL/$DARKBLUE$relation_name$NORMAL (joined) ${GREEN}@${NORMAL}"
+            } 3>&1 1>&2 2>&3 | logstderr "$DARKYELLOW$service$NORMAL/$DARKBLUE$relation_name$NORMAL (joined) ${RED}@$NORMAL" 3>&1 1>&2 2>&3
             errlvl="$(cat "$relation_dir/errlvl")" || {
-                err "Relation script '$script_name' in $DARKYELLOW$charm$NORMAL" \
+                err "Relation script '$script_name' in $DARKPINK$charm$NORMAL" \
                     "failed before outputing an errorlevel."
                 ((errlvl |= "1" ))
             }
@@ -1435,13 +1444,13 @@ _run_service_relation () {
                 ((errlvl |= "$?" ))
             fi
             if [ "$errlvl" != 0 ]; then
-                err "Relation $DARKBLUE$relation_name$NORMAL on $DARKYELLOW$charm$NORMAL failed to run properly."
+                err "Relation $DARKBLUE$relation_name$NORMAL on $DARKYELLOW$service$NORMAL failed to run properly."
             fi
         else
-            verb "No relation script '$script_name' in charm $DARKYELLOW$charm$NORMAL. Ignoring."
+            verb "No relation script '$script_name' in charm $DARKPINK$charm$NORMAL. Ignoring."
         fi
     else
-        err "Relation $DARKBLUE$relation_name$NORMAL on $DARKYELLOW$target_charm$NORMAL failed to run properly."
+        err "Relation $DARKBLUE$relation_name$NORMAL on $DARKYELLOW$target_service$NORMAL failed to run properly."
     fi
 
     if [ "$target_errlvl" == 0 -a "$errlvl" == 0 ]; then
@@ -1473,18 +1482,21 @@ _get_compose_relations_cached () {
                     case "$(echo "$relation_def" | shyaml get-type 2>/dev/null)" in
                     "str")
                         target_service="$(echo "$relation_def" | shyaml get-value 2>/dev/null)"
-                        tech_dep="$(get_charm_tech_dep_orientation_for_relation "$target_service" "$relation_name")"
+                        target_charm=$(get_service_charm "$target_service")
+                        tech_dep="$(get_charm_tech_dep_orientation_for_relation "$target_charm" "$relation_name")"
                         echo -en "$relation_name\0$target_service\0\0$tech_dep\0"
                         ;;
                     "sequence")
                         while read-0 target_service; do
-                            tech_dep="$(get_charm_tech_dep_orientation_for_relation "$target_service" "$relation_name")"
+                            target_charm=$(get_service_charm "$target_service")
+                            tech_dep="$(get_charm_tech_dep_orientation_for_relation "$target_charm" "$relation_name")"
                             echo -en "$relation_name\0$target_service\0\0$tech_dep\0"
                         done < <(echo "$relation_def" | shyaml get-values-0 2>/dev/null)
                         ;;
                     "struct")
                         while read-0 target_service relation_config; do
-                            tech_dep="$(get_charm_tech_dep_orientation_for_relation "$target_service" "$relation_name")"
+                            target_charm=$(get_service_charm "$target_service")
+                            tech_dep="$(get_charm_tech_dep_orientation_for_relation "$target_charm" "$relation_name")"
                             echo -en "$relation_name\0$target_service\0$relation_config\0$tech_dep\0"
                         done < <(echo "$relation_def" | shyaml key-values-0 2>/dev/null)
                         ;;
@@ -1539,18 +1551,20 @@ run_service_relations () {
             [ "${loaded[$subservice]}" ] && continue
 
             export BASE_SERVICE_NAME=$service
-            MASTER_BASE_CHARM_NAME=$(get_top_master_charm_for_service "$subservice") || return 1
+            MASTER_BASE_SERVICE_NAME=$(get_top_master_service_for_service "$subservice") || return 1
+            MASTER_BASE_CHARM_NAME=$(get_service_charm "$MASTER_BASE_SERVICE_NAME") || return 1
             RELATION_BASE_COMPOSE_DEF=$(get_compose_service_def "$subservice") || return 1
-            export RELATION_BASE_COMPOSE_DEF MASTER_BASE_CHARM_NAME
+            export RELATION_BASE_COMPOSE_DEF MASTER_BASE_{CHARM,SERVICE}_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 "$target_service") || return 1
+                MASTER_TARGET_SERVICE_NAME=$(get_top_master_service_for_service "$target_service") || return 1
+                MASTER_TARGET_CHARM_NAME=$(get_service_charm "$MASTER_TARGET_SERVICE_NAME") || return 1
                 RELATION_TARGET_COMPOSE_DEF=$(get_compose_service_def "$target_service") || return 1
-                export MASTER_TARGET_CHARM_NAME RELATION_TARGET_COMPOSE_DEF
+                export RELATION_TARGET_COMPOSE_DEF MASTER_TARGET_{CHARM,SERVICE}_NAME
 
                 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"
@@ -1564,7 +1578,7 @@ export -f run_service_relations
 
 
 _run_service_action_direct() {
-    local service="$1" action="$2" charm  _dummy
+    local service="$1" action="$2" charm _dummy
     shift; shift
 
     read-0 charm || true  ## against 'set -e' that could be setup in parent scripts
@@ -1584,15 +1598,15 @@ _run_service_action_direct() {
             export METADATA_CONFIG=$(charm.metadata "$charm")
             export SERVICE_NAME=$service
             export ACTION_NAME=$action
-            export CONTAINER_NAME=$(get_top_master_charm_for_service "$service")
+            export CONTAINER_NAME=$(get_top_master_service_for_service "$service")
             export DOCKER_BASE_IMAGE=$(service_base_docker_image "$CONTAINER_NAME")
             export SERVICE_DATASTORE="$DATASTORE/$service"
             export SERVICE_CONFIGSTORE="$CONFIGSTORE/$service"
             exname="$exname $ACTION_NAME $SERVICE_NAME" \
                     stdbuf -oL -eL bash -c 'charm.run_direct_action "$@"' -- "$charm" "$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
+        ) | logstdout "$DARKYELLOW$service$NORMAL/${DARKCYAN}$action${NORMAL} ${GREEN}@${NORMAL}"
+    } 3>&1 1>&2 2>&3 | logstderr "$DARKYELLOW$service$NORMAL/${DARKCYAN}$action${NORMAL} ${RED}@$NORMAL" 3>&1 1>&2 2>&3
     if ! [ -e "$action_errlvl_file" ]; then
         err "Action $DARKYELLOW$service$NORMAL:$DARKCYAN$action$NORMAL has failed without having time" \
             "to output an errlvl"
@@ -1606,14 +1620,14 @@ _run_service_action_relation() {
     local service="$1" action="$2" charm target_charm relation_name relation_config _dummy
     shift; shift
 
-    read-0 charm target_charm relation_name relation_config || true
+    read-0 charm target_service target_charm relation_name relation_config || true
 
     if read-0 _dummy || [ "$_dummy" ]; then
         print_syntax_error "$FUNCNAME: too many arguments in action descriptor"
         return 1
     fi
 
-    export RELATION_DATA_FILE=$(get_relation_data_file "$charm" "$target_charm" "$relation_name" "$relation_config")
+    export RELATION_DATA_FILE=$(get_relation_data_file "$service" "$target_service" "$relation_name" "$relation_config")
 
     compose_file=$(get_compose_yml_location) || return 1
     export action_errlvl_file="$state_tmpdir/action-$service-$charm-$action-errlvl"
@@ -1623,18 +1637,20 @@ _run_service_action_relation() {
             set +e  ## Prevents unwanted leaks from parent shell
             export METADATA_CONFIG=$(charm.metadata "$charm")
             export SERVICE_NAME=$service
+            export RELATION_TARGET_SERVICE="$target_service"
             export RELATION_TARGET_CHARM="$target_charm"
+            export RELATION_BASE_SERVICE="$service"
             export RELATION_BASE_CHARM="$charm"
             export ACTION_NAME=$action
-            export CONTAINER_NAME=$(get_top_master_charm_for_service "$service")
+            export CONTAINER_NAME=$(get_top_master_service_for_service "$service")
             export DOCKER_BASE_IMAGE=$(service_base_docker_image "$CONTAINER_NAME")
             export SERVICE_DATASTORE="$DATASTORE/$service"
             export SERVICE_CONFIGSTORE="$CONFIGSTORE/$service"
             exname="$exname $ACTION_NAME $SERVICE_NAME" \
                     stdbuf -oL -eL bash -c 'charm.run_relation_action "$@"' -- "$target_charm" "$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
+        ) | logstdout "$DARKYELLOW$service$NORMAL/${DARKCYAN}$action${NORMAL} ${GREEN}@${NORMAL}"
+    } 3>&1 1>&2 2>&3 | logstderr "$DARKYELLOW$service$NORMAL/${DARKCYAN}$action${NORMAL} ${RED}@$NORMAL" 3>&1 1>&2 2>&3
     if ! [ -e "$action_errlvl_file" ]; then
         err "Action $DARKYELLOW$service$NORMAL:$DARKCYAN$action$NORMAL has failed without having time" \
             "to output an errlvl"
@@ -1646,7 +1662,7 @@ export -f _run_service_action_relation
 
 
 get_relation_data_dir() {
-    local charm="$1" target_charm="$2" relation_name="$3" cache_file="$state_tmpdir/$FUNCNAME.cache.$1"
+    local service="$1" target_service="$2" relation_name="$3" cache_file="$state_tmpdir/$FUNCNAME.cache.$1"
     if [ -e "$cache_file" ]; then
         # debug "$FUNCNAME: cache hit ($*)"
         cat "$cache_file"
@@ -1654,7 +1670,7 @@ get_relation_data_dir() {
     fi
 
     project=$(get_default_project_name) || return 1
-    relation_dir="$VARDIR/relations/$project/$charm-$target_charm/$relation_name"
+    relation_dir="$VARDIR/relations/$project/${service}-${target_service}/$relation_name"
     if ! [ -d "$relation_dir" ]; then
         mkdir -p "$relation_dir" || return 1
         chmod go-rwx "$relation_dir" || return 1  ## protecting this directory
@@ -1665,9 +1681,9 @@ export -f get_relation_data_dir
 
 
 get_relation_data_file() {
-    local charm="$1" target_charm="$2" relation_name="$3" relation_config="$4"
+    local service="$1" target_service="$2" relation_name="$3" relation_config="$4"
 
-    relation_dir=$(get_relation_data_dir "$charm" "$target_charm" "$relation_name") || return 1
+    relation_dir=$(get_relation_data_dir "$service" "$target_service" "$relation_name") || return 1
     relation_data_file="$relation_dir/data"
 
     new=
@@ -1693,7 +1709,7 @@ export -f get_relation_data_file
 
 has_service_action () {
     local service="$1" action="$2" cache_file="$state_tmpdir/$FUNCNAME.cache.$1" \
-          charm target_charm
+          charm target_charm relation_name target_service relation_config _tech_dep
     if [ -e "$cache_file" ]; then
         # debug "$FUNCNAME: cache hit ($*)"
         cat "$cache_file"
@@ -1708,17 +1724,19 @@ has_service_action () {
         echo -en "direct\0$charm" | tee "$cache_file"
         return 0
     fi
+
     ## Action provided by relation ?
-    while read-0 relation_name target_service relation_config tech_dep; do
+
+    while read-0 relation_name target_service relation_config _tech_dep; do
         target_charm=$(get_service_charm "$target_service") || return 1
         if charm.has_relation_action "$target_charm" "$relation_name" "$action" >/dev/null; then
-            echo -en "relation\0$charm\0$target_charm\0$relation_name\0$relation_config" | tee "$cache_file"
+            echo -en "relation\0$charm\0$target_service\0$target_charm\0$relation_name\0$relation_config" | tee "$cache_file"
             return 0
         fi
     done < <(get_compose_relations "$service")
 
     return 1
-    # master=$(get_top_master_charm_for_service "$charm")
+    # master=$(get_top_master_service_for_service "$service")
     # [ "$master" == "$charm" ] && return 1
 
     # has_service_action "$master" "$action"
@@ -1782,9 +1800,9 @@ export -f get_compose_relation_config
 # export -f get_compose_relation_config_for_service
 
 
-_get_master_charm_for_service_cached () {
+_get_master_service_for_service_cached () {
     local service="$1" charm="$2" metadata="$3" cache_file="$CACHEDIR/$FUNCNAME.cache.$(echo "$*" | md5_compat)" \
-          charm requires master_charm target_charm target_service service_def
+          charm requires master_charm target_charm target_service service_def found
     if [ -e "$cache_file" ]; then
         # debug "$FUNCNAME: STATIC cache hit ($1)"
         cat "$cache_file"
@@ -1793,15 +1811,15 @@ _get_master_charm_for_service_cached () {
     fi
 
     if [ "$(echo "$metadata" | shyaml get-value "subordinate" 2>/dev/null)" != "True" ]; then
-        ## just return charm name
-        echo "$charm" | tee "$cache_file"
+        ## just return service name
+        echo "$service" | tee "$cache_file"
         return 0
     fi
 
     ## fetch the container relation
     requires="$(echo "$metadata" | shyaml get-value "requires" 2>/dev/null)"
     if [ -z "$requires" ]; then
-        die "Charm $DARKYELLOW$charm$NORMAL is a subordinate but does not have any 'requires' " \
+        die "Charm $DARKPINK$charm$NORMAL is a subordinate but does not have any 'requires' " \
             "section."
     fi
     found=
@@ -1812,7 +1830,7 @@ _get_master_charm_for_service_cached () {
         }
     done < <(echo "$requires" | shyaml key-values-0 2>/dev/null)
     if [ -z "$found" ]; then
-        die "Charm $DARKYELLOW$charm$NORMAL is a subordinate but does not have any required relation declaration with" \
+        die "Charm $DARKPINK$charm$NORMAL is a subordinate but does not have any required relation declaration with" \
             " ${WHITE}scope${NORMAL} set to 'container'."
     fi
 
@@ -1836,12 +1854,11 @@ _get_master_charm_for_service_cached () {
             "${DARKYELLOW}$service$NORMAL compose definition."
         return 1
     fi
-    master_charm=$(get_service_charm "$target_service") || return 1
-    echo "$master_charm" | tee "$cache_file"
+    echo "$target_service" | tee "$cache_file"
 }
-export -f _get_master_charm_for_service_cached
+export -f _get_master_service_for_service_cached
 
-get_master_charm_for_service() {
+get_master_service_for_service() {
     local service="$1" cache_file="$state_tmpdir/$FUNCNAME.cache.$1" \
           charm metadata result
 
@@ -1852,17 +1869,17 @@ get_master_charm_for_service() {
     fi
 
     charm=$(get_service_charm "$service") || return 1
-    metadata=$(charm.metadata "$charm") || {
-        err "Failed to access metadata of charm $DARKYELLOW$charm$NORMAL"
-        return 1
+    metadata=$(charm.metadata "$charm" 2>/dev/null) || {
+        metadata=""
+        warn "No charm $DARKPINK$charm$NORMAL found."
     }
-    result=$(_get_master_charm_for_service_cached "$service" "$charm" "$metadata") || return 1
+    result=$(_get_master_service_for_service_cached "$service" "$charm" "$metadata") || return 1
     echo "$result" | tee "$cache_file"
 }
-export -f get_master_charm_for_service
+export -f get_master_service_for_service
 
 
-get_top_master_charm_for_service() {
+get_top_master_service_for_service() {
     local service="$1" cache_file="$state_tmpdir/$FUNCNAME.cache.$1" \
           current_service
 
@@ -1874,14 +1891,14 @@ get_top_master_charm_for_service() {
 
     current_service="$service"
     while true; do
-        master_service=$(get_master_charm_for_service "$current_service") || return 1
+        master_service=$(get_master_service_for_service "$current_service") || return 1
         [ "$master_service" == "$current_service" ] && break
         current_service="$master_service"
     done
     echo "$current_service" | tee "$cache_file"
     return 0
 }
-export -f get_top_master_charm_for_service
+export -f get_top_master_service_for_service
 
 
 ##
@@ -1889,7 +1906,7 @@ export -f get_top_master_charm_for_service
 ## docker-compose entry (thinking of subordinates). The result
 ## will be merge with master charms.
 _get_docker_compose_mixin_from_metadata_cached() {
-    local charm="$1" metadata="$2" cache_file="$CACHEDIR/$FUNCNAME.cache.$(echo "$*" | md5_compat)" \
+    local service="$1" charm="$2" metadata="$3" cache_file="$CACHEDIR/$FUNCNAME.cache.$(echo "$*" | md5_compat)" \
           metadata_file metadata volumes docker_compose subordinate image
     if [ -e "$cache_file" ]; then
         #debug "$FUNCNAME: STATIC cache hit $1"
@@ -1904,7 +1921,7 @@ _get_docker_compose_mixin_from_metadata_cached() {
         volumes=$(
             for resource_type in data config; do
                 while read-0 resource; do
-                    eval "echo \"  - \$${resource_type^^}STORE/\$charm\$resource:\$resource:rw\""
+                    eval "echo \"  - \$${resource_type^^}STORE/\$service\$resource:\$resource:rw\""
                 done < <(echo "$metadata" | shyaml get-values-0 "${resource_type}-resources" 2>/dev/null)
             done
             while read-0 resource; do
@@ -1925,7 +1942,7 @@ _get_docker_compose_mixin_from_metadata_cached() {
         if [ "$volumes" ]; then
             mixin=$(merge_yaml_str "$mixin" "$(echo -en "volumes:\n$volumes")") || {
                 err "Failed to merge mixin with ${WHITE}docker-compose${NORMAL} option" \
-                    "from charm ${DARKYELLOW}$charm$NORMAL."
+                    "from charm ${DARKPINK}$charm$NORMAL."
                 return 1
             }
         fi
@@ -1934,7 +1951,7 @@ _get_docker_compose_mixin_from_metadata_cached() {
         if [ "$docker_compose" ]; then
             mixin=$(merge_yaml_str "$mixin" "$docker_compose") || {
                 err "Failed to merge mixin with ${WHITE}docker-compose${NORMAL} option" \
-                    "from charm ${DARKYELLOW}$charm$NORMAL."
+                    "from charm ${DARKPINK}$charm$NORMAL."
                 return 1
             }
         fi
@@ -1957,7 +1974,7 @@ _get_docker_compose_mixin_from_metadata_cached() {
             err "Subordinate charm can not have a 'build' sub directory."
             return 1
         fi
-        image_or_build_statement="build: $charm/build"
+        image_or_build_statement="build: $(charm.get_dir "$charm")/build"
     fi
     if [ "$image_or_build_statement" ]; then
         mixin=$(merge_yaml_str "$mixin" "$image_or_build_statement")
@@ -1968,15 +1985,15 @@ export -f _get_docker_compose_mixin_from_metadata_cached
 
 
 get_docker_compose_mixin_from_metadata() {
-    local charm="$1" cache_file="$state_tmpdir/$FUNCNAME.cache.$1"
+    local service="$1" charm="$2" cache_file="$state_tmpdir/$FUNCNAME.cache.$1"
     if [ -e "$cache_file" ]; then
         #debug "$FUNCNAME: SESSION cache hit ($*)"
         cat "$cache_file"
         return 0
     fi
 
-    metadata="$(charm.metadata "$charm")" || return 1
-    mixin=$(_get_docker_compose_mixin_from_metadata_cached "$charm" "$metadata") || return 1
+    metadata="$(charm.metadata "$charm" 2>/dev/null)"
+    mixin=$(_get_docker_compose_mixin_from_metadata_cached "$service" "$charm" "$metadata") || return 1
     echo "$mixin" | tee "$cache_file"
 }
 export -f get_docker_compose_mixin_from_metadata
@@ -2032,11 +2049,12 @@ launch_docker_compose() {
     fi
 
     ## XXXvlab: could be more specific and only link the needed charms
-    for charm in $(shyaml keys services < "$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
+    ## XXXvlab: why do we need these links ? If this is for the build command, then it is not useful anymore.
+    # for charm in $(shyaml keys services < "$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"
 
     {
@@ -2110,7 +2128,7 @@ get_master_services() {
     local loaded master_service
     declare -A loaded
     for service in "$@"; do
-        master_service=$(get_top_master_charm_for_service "$service") || return 1
+        master_service=$(get_top_master_service_for_service "$service") || return 1
         if [ "${loaded[$master_service]}" ]; then
             continue
         fi
@@ -2496,7 +2514,7 @@ case "$action" in
                 read-0 action_type
                 case "$action_type" in
                     "relation")
-                        read-0 _ target_service relation_name
+                        read-0 _ target_service _target_charm relation_name
                         debug "Found action $DARKYELLOW${action_posargs[0]}$NORMAL/$DARKBLUE$relation_name$NORMAL/$DARKCYAN$action$NORMAL (in $DARKYELLOW$target_service$NORMAL)"
                         ;;
                     "direct")