new: database library provided to charm.

bin/compose

@@ -49,6 +49,18 @@ quick_cat_file() { quick_cat_stdin < "$1"; }
 quick_cat_stdin() { local IFS=''; while read -r line; do echo "$line"; done ; }
 export -f quick_cat_file quick_cat_stdin md5_compat
 
+clean_cache() {
+    local i=0
+    for f in $(ls -t "$CACHEDIR/"*.cache.* 2>/dev/null | tail -n +500); do
+        ((i++))
+        rm -f "$f"
+    done
+    if (( i > 0 )); then
+        debug "${WHITE}Cleaned cache:${NORMAL} Removed $((i)) elements (current cache size is $(du -sh "$CACHEDIR" | cut -f 1))"
+    fi
+}
+
+
 trap_add "EXIT" clean_cache
 
 usage="$exname CHARM"'
@@ -330,6 +342,219 @@ get_file() {
 export -f get_file
 
 
+##
+## Common database lib
+##
+
+_clean_docker() {
+    local _DB_NAME="$1" container_id="$2"
+    (
+        set +e
+        debug "Removing container $_DB_NAME"
+        docker stop "$container_id"
+        docker rm "$_DB_NAME"
+        rm -vf "/tmp/${_DB_NAME}.state"
+    )
+}
+export -f _clean_docker
+
+
+are_files_locked_in_dir() {
+    local dir="$1" device hdev ldev
+    device=$(stat -c %d "$dir") || {
+        err "Can't stat %d."
+        return 1
+    }
+    device=$(printf "%04x" $device)
+    hdev=${device:0:2}
+    ldev=${device:2:2}
+    inodes=$(find "$dir" -printf ':%i:\n')
+
+    found=
+    while read -r inode; do
+        debug "try inode:$inode"
+        if [[ "$inodes" == *":$inode:"* ]]; then
+            found=1
+            break
+        fi
+    done < <(cat /proc/locks | grep " $hdev:$ldev:" | sed -r "s/^.*$hdev:$ldev:([0-9]+).*$/\1/g") 
+
+    [ "$found" ]
+}
+export -f are_files_locked_in_dir
+
+export _PID="$$"
+ensure_db_docker_running () {
+
+    _DB_NAME="db_${DB_NAME}_${_PID}"
+    if [ -e "/tmp/${_DB_NAME}.state" ]; then
+        export DOCKER_IP="$(cat "/tmp/${_DB_NAME}.state")"
+        debug "Re-using previous docker/connection '$DOCKER_IP'."
+        _set_db_params "$DOCKER_IP"
+        return 0
+    fi
+
+    if [ -e "/tmp/${_DB_NAME}.working" ]; then
+        ## avoid recursive calls.
+        if [ -z "$DOCKER_IP" ]; then
+            err "Currently figuring up DOCKER_IP, please set it yourself before this call if needed."
+            return 1
+        else
+            debug "Ignoring recursive call."
+        fi
+        return 0
+    fi
+
+    touch "/tmp/${_DB_NAME}.working"
+
+    docker rm "$_DB_NAME" 2>/dev/null || true
+
+    host_db_working_dir="$DATASTORE/${SERVICE_NAME}$DB_DATADIR"
+
+    if is_db_locked; then
+        info "Some process is using '$host_db_working_dir'. Trying to find a docker that would do this..."
+        found=
+        for docker_id in $(docker ps -q); do
+            has_volume_mounted=$(
+                docker inspect \
+                       --format "{{range .Mounts}}{{if eq .Destination \"$DB_DATADIR\"}}{{.Source}}{{end}}{{end}}" \
+                       "$docker_id")
+            if [ "$has_volume_mounted" == "$host_db_working_dir" ]; then
+                found="$docker_id"
+                break
+            fi
+        done
+        if [ -z "$found" ]; then
+            err "Please shutdown any other docker using this directory."
+            return 1
+        fi
+        export container_id="$found"
+        info "Found docker $docker_id is already running."
+    else
+        verb "Database is not locked."
+        if ! docker_has_image "$DOCKER_BASE_IMAGE"; then
+            docker pull "$DOCKER_BASE_IMAGE"
+        fi
+
+        docker_opts=
+        if [ -f "$DB_PASSFILE" ]; then
+            verb "Found and using '$DB_PASSFILE'."
+            docker_opts="$db_docker_opts -v $SERVER_ROOT_PREFIX$DB_PASSFILE:$DB_PASSFILE"
+        fi
+        debug docker run -d \
+              --name "$_DB_NAME" \
+              $docker_opts \
+              -v "$host_db_working_dir:$DB_DATADIR" \
+              "$DOCKER_BASE_IMAGE"
+        if ! container_id=$(
+                docker run -d \
+                       --name "$_DB_NAME" \
+                       $docker_opts \
+                       -v "$host_db_working_dir:$DB_DATADIR" \
+                       "$DOCKER_BASE_IMAGE"
+             ); then
+            err "'docker run' failed !"
+            _clean_docker "$_DB_NAME" "$container_id"
+            rm "/tmp/${_DB_NAME}.working"
+            return 1
+        fi
+        trap_add EXIT,ERR "_clean_docker '$_DB_NAME' '$container_id'"
+
+    fi
+
+
+    if DOCKER_IP=$(wait_for_docker_ip "$container_id"); then
+        echo "$DOCKER_IP" > "/tmp/${_DB_NAME}.state"
+        debug "written /tmp/${_DB_NAME}.state"
+        rm "/tmp/${_DB_NAME}.working"
+        _set_db_params "$DOCKER_IP"
+        return 0
+    else
+        err "Db not found. Docker logs follows:"
+        docker logs --tail=5 "$container_id" 2>&1 | prefix "  | " >&2
+        rm "/tmp/${_DB_NAME}.working"
+        return 1
+    fi
+}
+export -f ensure_db_docker_running
+
+## Require to set $db_docker_opts if needed, and $DB_PASSFILE
+##
+_dcmd() {
+    local docker_opts command="$1"
+    shift
+
+    debug "Db> $command $@"
+
+    if [ -f "$DB_PASSFILE" ]; then
+        verb "Found and using '$DB_PASSFILE'."
+        db_docker_opts="$db_docker_opts -v $SERVER_ROOT_PREFIX$DB_PASSFILE:$DB_PASSFILE"
+    fi
+
+    debug docker run -i --rm \
+           $db_docker_opts \
+           --entrypoint "$command" "$DOCKER_BASE_IMAGE" $db_cmd_opts "$@"
+    docker run -i --rm \
+           $db_docker_opts \
+           --entrypoint "$command" "$DOCKER_BASE_IMAGE" $db_cmd_opts "$@"
+}
+export -f _dcmd
+
+
+## Executes code through db
+dcmd () {
+
+    [ "$DB_NAME" ] || print_syntax_error "$FUNCNAME: You must provide \$DB_NAME."
+    [ "$DB_DATADIR" ] || print_syntax_error "$FUNCNAME: You must provide \$DB_DATADIR."
+    [ "$DB_PASSFILE" ] || print_syntax_error "$FUNCNAME: You must provide \$DB_PASSFILE."
+    [ "$_PID" ] || print_syntax_error "$FUNCNAME: You must provide \$_PID."
+    [ "$(type -t is_db_locked)" == "function" ] || print_syntax_error "$FUNCNAME: You must provide function 'is_db_locked'."
+    [ "$(type -t _set_db_params)" == "function" ] || print_syntax_error "$FUNCNAME: You must provide function '_set_db_params'."
+    [ "$(type -t ddb)" == "function" ] || print_syntax_error "$FUNCNAME: You must provide function 'ddb'."
+
+    ensure_db_docker_running </dev/null || return 1
+
+    _dcmd "$@"
+}
+export -f dcmd
+
+## Warning: requires a ``ddb`` matching current database to be checked
+wait_for_docker_ip() {
+   local name=$1 timeout=5 timeout_count=0 DOCKER_IP= DB_OK=
+   while [ -z "$DOCKER_IP" ]; do
+       sleep 1
+       DOCKER_IP=$(docker inspect --format='{{.NetworkSettings.IPAddress}}' "$name" 2>/dev/null)
+       verb "[1/2] Waiting for docker $name... ($[timeout_count + 1]/$timeout)"
+       ((timeout_count++)) || true
+       if [ "$timeout_count" == "$timeout" ]; then
+          err "${RED}timeout error${NORMAL}(${timeout}s):"\
+              "Could not find '$name' docker" \
+              "container's IP."
+          return 1
+       fi
+   done
+   verb "[1/2] Found docker $name IP: $DOCKER_IP"
+   timeout_count=0
+   DB_OK=
+   _set_db_params "$DOCKER_IP"
+   while [ -z "$DB_OK" ]; do
+       sleep 1
+       echo "SELECT 1;" | ddb >/dev/null  && DB_OK=1
+       verb "[2/2] Waiting for db service from docker $name... ($[timeout_count + 1]/$timeout)"
+       ((timeout_count++)) || true
+       if [ "$timeout_count" == "$timeout" ]; then
+          err "${RED}timeout error${NORMAL}(${timeout}s):"\
+              "Could not connect to db on $DOCKER_IP." \
+              "container's IP."
+          return 1
+       fi
+   done
+   verb "[2/2] Db is ready !"
+   echo "$DOCKER_IP"
+   return 0
+}
+export -f wait_for_docker_ip
+
 ##
 ## Arrays
 ##