Add acquis docker start script and add inside readme

docker/README.md

@@ -285,6 +285,7 @@ config.yaml) each time the container is run.
 | __Agent__               | | (these don't work with DISABLE_AGENT) |
 | `TYPE`                  | | [`Labels.type`](https://docs.crowdsec.net/Crowdsec/v1/references/acquisition/) for file in time-machine: `-e TYPE="<type>"` |
 | `DSN`                   | | Process a single source in time-machine: `-e DSN="file:///var/log/toto.log"` or `-e DSN="cloudwatch:///your/group/path:stream_name?profile=dev&backlog=16h"` or `-e DSN="journalctl://filters=_SYSTEMD_UNIT=ssh.service"` |
+| `ACQUIS_<name>`        | | Create a file within `acquis.d` with `<name>` as filename and value as a base64 encoded string (base64 -e -w0) which is decoded on startup to be file contents |
 |                         | | |
 | __Bouncers__            | | |
 | `BOUNCER_KEY_<name>`    | | Register a bouncer with the name `<name>` and a key equal to the value of the environment variable. |

docker/docker_start.sh

@@ -365,6 +365,15 @@ for BOUNCER in /run/secrets/@(bouncer_key|BOUNCER_KEY)* ; do
 done
 shopt -u nullglob extglob
 
+## Create acquisition files
+for ACQUIS in $(compgen -A variable | grep -i ACQUIS); do
+    CONTENT=$(printf '%s' "${!ACQUIS}" | base64 -d)
+    NAME=$(printf '%s' "$ACQUIS" | cut -d_  -f2-)
+    if [[ -n $CONTENT ]] && [[ -n $NAME ]]; then
+        echo "$CONTENT" > "/etc/crowdsec/acquis.d/$NAME.yaml"
+    fi
+done
+
 # set all options before validating the configuration
 
 conf_set_if "$CAPI_WHITELISTS_PATH" '.api.server.capi_whitelists_path = strenv(CAPI_WHITELISTS_PATH)'