fix: can't check from inside docker if host file exists.

This check can't be done, but the default standard location where it
should have been bind mounted should be testable. This is done on the
charm's end.

bin/compose

@@ -10,6 +10,20 @@
 ##
 
 
+get_os() {
+    local uname_output machine
+
+    uname_output="$(uname -s)"
+    case "${uname_output}" in
+        Linux*)   machine=linux;;
+        Darwin*)  machine=mac;;
+        CYGWIN*)  machine=cygwin;;
+        MINGW*)   machine=mingw;;
+        *)        machine="UNKNOWN:${uname_output}"
+    esac
+    echo "${machine}"
+}
+
 
 read-0() {
     local eof= IFS=''
@@ -49,7 +63,7 @@ is_volume_used() {
 
 
 clean_unused_sessions() {
-    for f in /var/lib/compose/sessions/*; do
+    for f in "$COMPOSE_VAR/sessions/"*; do
         [ -e "$f" ] || continue
         is_volume_used "$f" && continue
         rm -f "$f"
@@ -75,10 +89,10 @@ mk_docker_run_options() {
     docker_run_opts=("-v" "/var/run/docker.sock:/var/run/docker.sock")
 
     ## CACHE/DATA DIRS
-    docker_run_opts+=("-v" "/var/lib/compose:/var/lib/compose")
-    docker_run_opts+=("-v" "/var/cache/compose:/var/cache/compose")
+    docker_run_opts+=("-v" "$COMPOSE_VAR:/var/lib/compose")
+    docker_run_opts+=("-v" "$COMPOSE_CACHE:/var/cache/compose")
 
-    docker_run_opts+=("-v" "/etc/timezone:/etc/timezone:ro")
+    docker_run_opts+=("-v" "$TZ_PATH:/etc/timezone:ro")
 
 
     ## current dir
@@ -91,7 +105,7 @@ mk_docker_run_options() {
                     cd ..
                 done
              ); then
-        docker_path=/var/lib/compose/root/$(basename "$parent")
+        docker_path=$COMPOSE_VAR/root/$(basename "$parent")
         docker_run_opts+=("-v" "$parent:$docker_path:ro" \
                                "-w" "$docker_path")
     fi
@@ -102,23 +116,13 @@ mk_docker_run_options() {
     ##
 
     if [ -z "$DISABLE_SYSTEM_CONFIG_FILE" ]; then
-        if [ -r /etc/default/charm ]; then
-            docker_run_opts+=("-v" "/etc/default/charm:/etc/default/charm:ro")
-            . /etc/default/charm
-        fi
-
         ## XXXvlab: should provide YML config opportunities in possible parent dirs ?
         ##  userdir ? and global /etc/compose.yml ?
-        for cfgfile in /etc/compose.conf /etc/compose.local.conf \
-                                         /etc/default/compose /etc/compose/local.conf; do
+        for cfgfile in "${compose_config_files[@]}"; do
             [ -e "$cfgfile" ] || continue
             docker_run_opts+=("-v" "$cfgfile:$cfgfile:ro")
             . "$cfgfile"
         done
-        for cfgfile in /etc/default/datastore; do
-            [ -e "$cfgfile" ] || continue
-            docker_run_opts+=("-v" "$cfgfile:$cfgfile:ro")
-        done
     else
         docker_run_opts+=("-e" "DISABLE_SYSTEM_CONFIG_FILE=$DISABLE_SYSTEM_CONFIG_FILE")
     fi
@@ -133,7 +137,11 @@ mk_docker_run_options() {
     [ -L "$CHARM_STORE" ] && {
         CHARM_STORE=$(readlink "$CHARM_STORE") || exit 1
     }
-    docker_run_opts+=("-v" "$CHARM_STORE:/srv/charm-store:ro")
+    docker_run_opts+=(
+        "-v" "$CHARM_STORE:/srv/charm-store:ro"
+        "-e" "CHARM_STORE=/srv/charm-store"
+        "-e" "HOST_CHARM_STORE=$CHARM_STORE"
+    )
     relink_subdirs /srv/charm-store/*
 
     ## DEFAULT_COMPOSE_FILE
@@ -148,21 +156,30 @@ mk_docker_run_options() {
     ## COMPOSE_YML_FILE
     if [ "${COMPOSE_YML_FILE+x}" ]; then
         if [ -e "${COMPOSE_YML_FILE}" ]; then
-            docker_run_opts+=("-v" "$COMPOSE_YML_FILE:/tmp/compose.yml:ro")
-            docker_run_opts+=("-e" "COMPOSE_YML_FILE=/tmp/compose.yml")
+            docker_run_opts+=(
+                "-v" "$COMPOSE_YML_FILE:/tmp/compose.yml:ro"
+                "-e" "COMPOSE_YML_FILE=/tmp/compose.yml"
+                "-e" "HOST_COMPOSE_YML_FILE=/tmp/compose.yml"
+            )
         fi
     fi
 
     ## DATASTORE
     if [ "${DATASTORE+x}" ]; then
-        docker_run_opts+=("-v" "$DATASTORE:/srv/datastore/data:rw")
-        docker_run_opts+=("-e" "DATASTORE=/srv/datastore/data")
+        docker_run_opts+=(
+            "-v" "$DATASTORE:/srv/datastore/data:rw"
+            "-e" "DATASTORE=/srv/datastore/data"
+            "-e" "HOST_DATASTORE=$DATASTORE"
+        )
     fi
 
     ## CONFIGSTORE
     if [ "${CONFIGSTORE+x}" ]; then
-        docker_run_opts+=("-v" "$CONFIGSTORE:/srv/datastore/config:rw")
-        docker_run_opts+=("-e" "CONFIGSTORE=/srv/datastore/config")
+        docker_run_opts+=(
+            "-v" "$CONFIGSTORE:/srv/datastore/config:rw"
+            "-e" "CONFIGSTORE=/srv/datastore/config"
+            "-e" "HOST_CONFIGSTORE=$CONFIGSTORE"
+        )
     fi
 
     docker_run_opts+=("-v" "$HOME/.docker:/root/.docker")
@@ -171,6 +188,7 @@ mk_docker_run_options() {
     docker_run_opts+=("-e" "COMPOSE_DOCKER_IMAGE=$COMPOSE_DOCKER_IMAGE")
 
     COMPOSE_LAUNCHER_BIN=$(readlink -f "${BASH_SOURCE[0]}")
+    docker_run_opts+=("-v" "$COMPOSE_LAUNCHER_BIN:/usr/local/bin/compose")
 
     filename=$(mktemp -p /tmp/ -t launch_opts-XXXXXXXXXXXXXXXX)
     {
@@ -178,19 +196,54 @@ mk_docker_run_options() {
     } > "$filename"
     sha=$(sha256sum "$filename")
     sha=${sha:0:64}
-    dest="/var/lib/compose/sessions/$sha"
+    dest="$COMPOSE_VAR/sessions/$sha"
     {
         printf "%s\0" "-v" "$dest:$dest"
         printf "%s\0" "-e" "COMPOSE_LAUNCHER_OPTS=$dest"
         printf "%s\0" "-e" "COMPOSE_LAUNCHER_BIN=$COMPOSE_LAUNCHER_BIN"
     } >> "$filename"
-    mkdir -p /var/lib/compose/sessions
+    mkdir -p "$COMPOSE_VAR"/sessions
     mv "$filename" "$dest"
     echo "$dest"
 }
 
 
 run() {
+    local os docker_run_opts
+
+    ## Order matters, files get to override vars
+    compose_config_files=(
+        /etc/default/charm
+        /etc/default/datastore
+        /etc/compose.conf
+        /etc/compose.local.conf
+        /etc/default/compose
+        ~/.compose/etc/local.conf
+        /etc/compose/local.conf
+    )
+
+    os=$(get_os)
+    case "$os" in
+        linux)
+            COMPOSE_VAR=/var/lib/compose
+            COMPOSE_CACHE=/var/cache/compose
+            ;;
+        mac)
+            if ! [ -e "$HOME/.compose/etc/timezone" ]; then
+                TZ=${TZ:-"Europe/Paris"}
+                echo "$TZ" > "$HOME"/.compose/etc/timezone
+            fi
+            TZ_PATH="$HOME"/.compose/etc/timezone
+            COMPOSE_VAR="$HOME"/.compose/lib
+            COMPOSE_CACHE="$HOME"/.compose/cache
+            ;;
+        *)
+            echo "System '$os' not supported yet." >&2
+            exit 1
+            ;;
+    esac
+
+
     docker_run_opts=()
     if [ -z "$COMPOSE_LAUNCHER_OPTS" ]; then
         clean_unused_sessions

bin/compose-core

@@ -731,7 +731,11 @@ ensure_db_docker_running () {
 
     docker rm "$_DB_NAME" 2>/dev/null || true
 
+    if [ "${HOST_DATASTORE+x}" ]; then
+        host_db_working_dir="$HOST_DATASTORE/${SERVICE_NAME}$DB_DATADIR"
+    else
         host_db_working_dir="$DATASTORE/${SERVICE_NAME}$DB_DATADIR"
+    fi
 
     if is_db_locked; then
         info "Some process is using '$host_db_working_dir'. Trying to find a docker that would do this..."
@@ -814,7 +818,7 @@ _dcmd() {
 
     debug "Db> $command $@"
 
-    if [ -f "$HOST_DB_PASSFILE" -a "$CLIENT_DB_PASSFILE" ]; then
+    if [ "$HOST_DB_PASSFILE" -a -f "$LOCAL_DB_PASSFILE" -a "$CLIENT_DB_PASSFILE" ]; then
         verb "Found and using '$HOST_DB_PASSFILE' as '$CLIENT_DB_PASSFILE'."
         docker_opts=("${db_docker_opts[@]}" "-v" "$HOST_DB_PASSFILE:$CLIENT_DB_PASSFILE")
     else