diff --git a/docker/.dockerignore b/docker/.dockerignore
new file mode 100644
index 0000000..dcf0102
--- /dev/null
+++ b/docker/.dockerignore
@@ -0,0 +1 @@
+/b/t/
diff --git a/docker/.gitignore b/docker/.gitignore
new file mode 100644
index 0000000..0797d89
--- /dev/null
+++ b/docker/.gitignore
@@ -0,0 +1,2 @@
+/b/
+/build.env.local
diff --git a/docker/build b/docker/build
index 9833541..65989cf 100755
--- a/docker/build
+++ b/docker/build
@@ -1,12 +1,6 @@
 #!/bin/bash
 # -*- coding: utf-8 mode: sh -*- vim:sw=4:sts=4:et:ai:si:sta:fenc=utf-8
 source /etc/ulibauto || exit 1
-cd "$scriptdir"
-
-NAME=ur/nutools
-BUILDDIR=b
-TRANSDIR="$BUILDDIR/t"
-ENVDIR=..
 
 function display_help() {
     uecho "$scriptname: construire $NAME
@@ -16,10 +10,33 @@ USAGE
 
 OPTIONS
     -b, --build
-    -n, --no-cache
-    -r, --run"
+    -n, --no-cache"
 }
 
+function do_prereqs() {
+    :
+}
+function do_build() {
+    local date; local -a args
+    setx date=date +%y%m%d
+    args=(
+        -f Dockerfile
+        -t $NAME:latest
+        --build-arg "date=$date"
+        ${no_cache:+--no-cache}
+    )
+
+    etitle "Création de l'image docker $NAME" \
+        docker build "${args[@]}" "$CTXDIR"
+}
+function do_run() {
+    docker run -it --rm "$NAME"
+}
+
+cd "$scriptdir"
+source ./build.env || die "Impossible de trouver build.env"
+[ -f build.env.local ] && source build.env.local
+
 auto=1
 prereqs=
 build=
@@ -36,24 +53,20 @@ parse_args "$@"; set -- "${args[@]}"
 
 if [ -n "$prereqs" ]; then
     build=
+    run=
 elif [ -n "$auto" ]; then
     build=1
 fi
 
-if [ -n "$build" ]; then
-    setx date=date +%y%m%d
-    args=(
-        -f Dockerfile
-        -t $NAME:latest
-        --build-arg "date=$date"
-        ${no_cache:+--no-cache}
-    )
+if [ -n "$prereqs" ]; then
+    do_prereqs "$@" || die
+fi
 
-    etitle "Création de l'image docker $NAME"
-    docker build "${args[@]}" "$ENVDIR"
-    eend
+if [ -n "$build" ]; then
+    do_build "$@" || die
 fi
 
 if [ -n "$run" ]; then
-    docker run -it --rm "$NAME"
+    do_run "$@" || die
 fi
+
diff --git a/docker/build.env b/docker/build.env
new file mode 100644
index 0000000..4b53837
--- /dev/null
+++ b/docker/build.env
@@ -0,0 +1,15 @@
+# -*- coding: utf-8 mode: sh -*- vim:sw=4:sts=4:et:ai:si:sta:fenc=utf-8
+# Nom de l'image
+NAME=ur/nutools
+# Build context pour docker
+CTXDIR=..
+# Répertoire contenant les fichiers nécessaire au build
+BUILDDIR=b
+# Répertoire temporaire pour construire les fichiers de BUILDDIR. Ce répertoire
+# n'est pas transmis au daemon docker
+TRANSDIR=b/t
+
+# Fonctions spécifiques
+#function do_prereqs() { :; }
+#function do_build() { :; }
+#function do_run() { :; }