Dynamically exclude roles based on host type

tools/play.sh

@@ -1,27 +1,51 @@
 #!/usr/bin/env bash
 
 HOSTS="$1"
+ROLE_LIST=( "virt-common" "docker" "apps" "postgresql" "proxy" )
 
-case $HOSTS in
-*:*)
-    ROLES="['virt-common']" ;;
-*app*)
-    ROLES="['virt-common', 'docker', 'apps']" ;;
-*db*)
-    ROLES="['virt-common', 'postgresql']" ;;
-*prx*|proxy*)
-    ROLES="['virt-common', 'docker', 'proxy']" ;;
-*)
-    ROLES="['virt-common']" ;;
-esac
+# Dynamically remove roles that are incompatible with a host
+OLDIFS="$IFS"
+IFS=:
+for target in $HOSTS; do
+    case $target in
+    *app*)
+        ROLE_LIST=( "${ROLE_LIST[@]/postgresql}" )
+        ROLE_LIST=( "${ROLE_LIST[@]/proxy}" )
+        ;;
+    *db*)
+        ROLE_LIST=( "${ROLE_LIST[@]/docker}" )
+        ROLE_LIST=( "${ROLE_LIST[@]/apps}" )
+        ROLE_LIST=( "${ROLE_LIST[@]/proxy}" )
+        ;;
+    *mda*|media*)
+        ROLE_LIST=( "${ROLE_LIST[@]/apps}" )
+        ROLE_LIST=( "${ROLE_LIST[@]/postgresql}" )
+        ROLE_LIST=( "${ROLE_LIST[@]/proxy}" )
+        ;;
+    *prx*|proxy*)
+        ROLE_LIST=( "${ROLE_LIST[@]/apps}" )
+        ROLE_LIST=( "${ROLE_LIST[@]/postgresql}" )
+        ;;
+    *)
+        ROLE_LIST=( "virt-common" ) ;;
+    esac
+done
+IFS="$OLDIFS"
 
+# Transform role list into JSON array
+ROLES="$(jq -c -M -n '$ARGS.positional | map(select(length > 0))' --args -- "${ROLE_LIST[@]}")"
+echo "Running roles $ROLES against $HOSTS"
+
+# Export vars for envsubst
 export HOSTS
 export ROLES
 
+# Execution of temporary envsubst'ed playbook
 PLAYBOOK="playbook-$(tr -dc A-Za-z < /dev/urandom | head -c 10).yml"
 envsubst < site.yml > "$PLAYBOOK"
 ansible-playbook "$PLAYBOOK"
 STATUS=$?
 
+# Clean up temporary playbook
 rm -f "$PLAYBOOK"
 exit $STATUS