diff --git a/Dockerfile b/Dockerfile
index 11d4fed..91391cb 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -62,8 +62,10 @@ COPY --from=build-image /opt /opt
 ENV PATH="/virtualenv/bin:$PATH"
 ENV VIRTUAL_ENV="/virtualenv"
 ENV LD_LIBRARY_PATH="/opt/oracle/instantclient"
+# IPv6 support is not enabled by default, only bind IPv4
+ENV QE_HOST="0.0.0.0"
 
 EXPOSE 9560/tcp
 VOLUME /config
-# IPv6 support is not enabled by default, only bind IPv4
-ENTRYPOINT ["query-exporter", "/config/config.yaml", "-H", "0.0.0.0"]
+WORKDIR /config
+ENTRYPOINT ["query-exporter"]
diff --git a/README.rst b/README.rst
index 91092f2..43fff69 100644
--- a/README.rst
+++ b/README.rst
@@ -15,10 +15,13 @@ Each query can be run on multiple databases, and update multiple metrics.
 
 The application is simply run as::
 
-  query-exporter config.yaml
+  query-exporter
 
-where the passed configuration file contains the definitions of the databases
-to connect and queries to perform to update metrics.
+which will look for a ``config.yaml`` configuration file in the current
+directory, containing the definitions of the databases to connect and queries
+to perform to update metrics.  The configuration file can be overridden by
+passing the ``--config`` option, or setting the ``QE_CONFIG`` environment
+variable.
 
 
 Configuration file format
@@ -502,8 +505,9 @@ included by passing ``--process-stats`` in the command line.
 Debugging / Logs
 ----------------
 
-You can enable extended logging using the ``-L`` commandline switch. Possible
-log levels are ``CRITICAL``, ``ERROR``, ``WARNING``, ``INFO``, ``DEBUG``.
+You can enable extended logging using the ``-L`` (or ``-log-level``) command
+line switch. Possible log levels are ``critical``, ``error``, ``warning``,
+``info``, ``debug``.
 
 
 Database engines
@@ -537,6 +541,8 @@ To configure the daemon:
 
 - create or edit ``/var/snap/query-exporter/current/config.yaml`` with the
   configuration
+- optionally, create a ``/var/snap/query-exporter/current/.env`` file with
+  environment variables definitions for additional config options
 - run ``sudo snap restart query-exporter``
 
 The snap has support for connecting the following databases:
@@ -561,12 +567,10 @@ where ``$CONFIG_DIR`` is the absolute path of a directory containing a
 ``config.yaml`` file, the configuration file to use. Alternatively, a volume
 name can be specified.
 
-
-A different ODBC driver version to use can be specified during image building,
-by passing ``--build-arg ODBC_bVERSION_NUMBER``, e.g.::
-
-  docker build . --build-arg ODBC_DRIVER_VERSION=17
-
+If, a ``.env`` file is present in the specified volume for ``/config``, its
+content is loaded and applied to the environment for the exporter. The location
+of the dotenv file can be customized by setting the ``QE_DOTENV`` environment
+variable.
 
 The image has support for connecting the following databases:
 
@@ -580,6 +584,14 @@ The image has support for connecting the following databases:
 
 A `Helm chart`_ to run the container in Kubernetes is also available.
 
+ODBC driver version
+~~~~~~~~~~~~~~~~~~~
+
+A different ODBC driver version to use can be specified during image building,
+by passing ``--build-arg ODBC_bVERSION_NUMBER``, e.g.::
+
+  docker build . --build-arg ODBC_DRIVER_VERSION=17
+
 
 .. _Prometheus: https://prometheus.io/
 .. _SQLAlchemy: https://www.sqlalchemy.org/
diff --git a/snap/local/daemon.sh b/snap/local/daemon.sh
index 1afb69d..8ad5767 100755
--- a/snap/local/daemon.sh
+++ b/snap/local/daemon.sh
@@ -1,7 +1,5 @@
 #!/bin/sh -e
 
-CONFIG_FILE="$SNAP_DATA/config.yaml"
+[ -r "$SNAP_DATA/config.yaml" ] || snapctl stop "$SNAP_INSTANCE_NAME"
 
-[ -r "$CONFIG_FILE" ] || snapctl stop "$SNAP_INSTANCE_NAME"
-
-exec "$SNAP/bin/query-exporter" -H 0.0.0.0 :: -- "$CONFIG_FILE"
+exec env -C "$SNAP_DATA" "$SNAP/bin/query-exporter" --
diff --git a/snap/local/query-exporter.completion b/snap/local/query-exporter.completion
deleted file mode 100644
index 6b5575a..0000000
--- a/snap/local/query-exporter.completion
+++ /dev/null
@@ -1,32 +0,0 @@
-
-# Run something, muting output or redirecting it to the debug stream
-# depending on the value of _ARC_DEBUG.
-__python_argcomplete_run() {
-    if [[ -z "$_ARC_DEBUG" ]]; then
-        "$@" 8>&1 9>&2 1>/dev/null 2>&1
-    else
-        "$@" 8>&1 9>&2 1>&9 2>&1
-    fi
-}
-
-_python_argcomplete() {
-    local IFS=$'\013'
-    local SUPPRESS_SPACE=0
-    if compopt +o nospace 2> /dev/null; then
-        SUPPRESS_SPACE=1
-    fi
-    COMPREPLY=( $(IFS="$IFS" \
-                  COMP_LINE="$COMP_LINE" \
-                  COMP_POINT="$COMP_POINT" \
-                  COMP_TYPE="$COMP_TYPE" \
-                  _ARGCOMPLETE_COMP_WORDBREAKS="$COMP_WORDBREAKS" \
-                  _ARGCOMPLETE=1 \
-                  _ARGCOMPLETE_SUPPRESS_SPACE=$SUPPRESS_SPACE \
-                  __python_argcomplete_run "$1") )
-    if [[ $? != 0 ]]; then
-        unset COMPREPLY
-    elif [[ $SUPPRESS_SPACE == 1 ]] && [[ "$COMPREPLY" =~ [=/:]$ ]]; then
-        compopt -o nospace
-    fi
-}
-complete -o nospace -o default -o bashdefault -F _python_argcomplete query-exporter
diff --git a/snap/snapcraft.yaml b/snap/snapcraft.yaml
index 1de6703..80b4b29 100644
--- a/snap/snapcraft.yaml
+++ b/snap/snapcraft.yaml
@@ -14,6 +14,8 @@ description: |
 
     - create or edit `/var/snap/query-exporter/current/config.yaml` with the
       configuration
+    - optionally, create a `/var/snap/query-exporter/current/.env` file with
+      environment variables definitions for additional config options
     - run `sudo snap restart query-exporter`
 
   Currently supported databases are:
@@ -83,12 +85,16 @@ parts:
       - libodbc2
       - libpq5
       - libxml2
+    override-build: |
+      craftctl default
+      _QUERY_EXPORTER_COMPLETE=bash_source query-exporter > "$CRAFT_PART_INSTALL/query-exporter.completion"
     prime:
       - bin/python3
       - bin/query-exporter
       - etc
       - lib
       - pyvenv.cfg
+      - query-exporter.completion
       - usr/lib
 
   wrappers: