justfile: Hide DOCKER_SOCKET command output

The justfile would use a command snippet starting with "set -x" to
determine the path of the Docker socket: this helps for debugging, but
most of the time it only prints cryptic messages to the console each
time we run just.

Make just print the output only when we set "debug=true". We cannot use
a variable in the triple-backquoted string, so we need a level of
indirection with a separate command and a call to shell(). We also need
to append a semicolon to "set -x" when set, and we use replace_regex()
for this.

Signed-off-by: Quentin Monnet <[email protected]>

justfile

@@ -46,17 +46,17 @@ _dev_env_container := _dpdk_sys_container_repo + "/dev-env:" + _dpdk_sys_contain
 _doc_env_container := _dpdk_sys_container_repo + "/doc-env:" + _dpdk_sys_container_tag
 _compile_env_container := _dpdk_sys_container_repo + "/compile-env:" + _dpdk_sys_container_tag
 _network := "host"
-export DOCKER_HOST := x"${DOCKER_HOST:-unix:///var/run/docker.sock}"
-export DOCKER_SOCK := ```
-  set -x
+_docker_sock_cmd := replace_regex(_just_debuggable_, ".*", "$0;") + '''
   declare -r DOCKER_HOST="${DOCKER_HOST:-unix:///var/run/docker.sock}"
   declare -r without_unix="${DOCKER_HOST##unix://}"
   if [ -S "${without_unix}" ]; then
     printf -- '%s' "${without_unix}"
   elif [ -S /var/run/docker.sock ]; then
     printf -- '%s' "/var/run/docker.sock"
   fi
-```
+'''
+export DOCKER_HOST := x"${DOCKER_HOST:-unix:///var/run/docker.sock}"
+export DOCKER_SOCK := shell(_docker_sock_cmd)
 
 # The git commit hash of the last commit to HEAD
 # We allow this command to fail in the sterile environment because git is not available there