Add rosbag_snapshot to keep a buffer of recent messages in memory for…

… saving to disk

Using `save_snapshot.sh` (or `rosrun rosbag_snapshot snapshot -t`), you can trigger it to save the current buffer to disk. This can be used to debug after an unexpected behavior occurs.

By default it is disabled.  It operates entirely independently of OM_ENABLE_RECORDING and OM_ENABLE_RECORDING_ALL.

config/mower_config.schema.json

@@ -401,6 +401,23 @@
           "description": "Set to true to record your session for debugging. Recordings will be stored in $HOME. Only enable for testing, otherwise your SD card will get full soon.",
           "x-environment-variable": "OM_ENABLE_RECORDING_ALL"
         },
+        "OM_SNAPSHOT_MEMORY_PER_TOPIC": {
+          "type": "number",
+          "default": 0.0,
+          "title": "Snapshot Buffer Memory per Topic",
+          "description": "Sets the maximum memory used per topic (in MB) by the Snapshot Buffer. The Snapshot Buffer stores a recent history of all messages sent, and can be dumped to disk using save_snapshot.sh. It is independent of OM_ENABLE_RECORDING",
+          "x-environment-variable": "OM_SNAPSHOT_MEMORY_PER_TOPIC",
+          "examples": [
+            5.0
+          ]
+        },
+        "OM_SNAPSHOT_DURATION": {
+          "type": "number",
+          "default": 1200,
+          "title": "Snapshot Buffer ",
+          "description": "Sets the maximum age (in seconds) of messages to store in the Snapshot Buffer. The Snapshot Buffer stores a recent history of all messages sent, and can be dumped to disk using save_snapshot.sh. It is independent of OM_ENABLE_RECORDING",
+          "x-environment-variable": "OM_SNAPSHOT_DURATION"
+        },
         "OM_RAIN_MODE": {
           "type": "string",
           "enum": [

config/mower_config.sh.example

@@ -60,10 +60,6 @@ export OM_MOWER_ESC_TYPE="xesc_mini"
 # Currently supported: ps3, steam_stick, steam_touch, xbox360
 export OM_MOWER_GAMEPAD="xbox360"
 
-# Set to true to record your session.
-# Output will be stored in your $HOME
-# export OM_ENABLE_RECORDING_ALL=False
-
 # Full Sound Support - But read on carefully:
 # Up to (and inclusive) OM hardware version 0.13.x, DFPlayer's power supply is set by default to 3.3V.
 # This is done by solder jumper "JP1" whose board track is by default at 3.3V.
@@ -185,7 +181,7 @@ export OM_ENABLE_MOWER=true
 
 # Set the automatic start value based on required behaviour
 #  2 - AUTO - mow whenever possible
-#  1 - SEMIAUTO - mow the entire map once then wait for manual start atgain
+#  1 - SEMIAUTO - mow the entire map once then wait for manual start again
 #  0 - MANUAL - mowing requires manual start (default if unset)
 export OM_AUTOMATIC_MODE=0
 
@@ -205,7 +201,7 @@ export OM_RAIN_DELAY_MINUTES=30
 ################################
 ##    External MQTT Broker    ##
 ################################
-# Set thes in order to publish status data to your external MQTT broker.
+# Set these in order to publish status data to your external MQTT broker.
 # This is for use with smart home.
 
 # export OM_MQTT_ENABLE=False
@@ -216,6 +212,25 @@ export OM_RAIN_DELAY_MINUTES=30
 # export OM_MQTT_TOPIC_PREFIX="openmower"
 
 
+################################
+##     Debugging Settings     ##
+################################
+
+# Set to true to record your session.
+# Output will be stored in your $HOME
+# export OM_ENABLE_RECORDING_ALL=False
+
+# OM_SNAPSHOT options can be used to enable an in-memory buffer of all recent
+# ROS messages for debugging. If something goes wrong, you can dump a
+# a snapshot to disk to reconstruct what happened and debug further,
+# using `$ ./utils/scripts/save_snapshot.sh output_file.bag`.
+# Note that this mechanism is entirely separate from OM_ENABLE_RECORDING_*.
+
+# Memory usage is measured in MB, and duration is measured in seconds.
+# export OM_SNAPSHOT_MEMORY_PER_TOPIC=5.0
+# export OM_SNAPSHOT_DURATION=1200
+
+
 # source the default values for the hardware platform.
 # you only need this line on non-docker installs. in the docker, it will be done automatically.
 # source $(rospack find open_mower)/params/hardware_specific/$OM_MOWER/default_environment.sh

src/open_mower/launch/include/_record.launch

@@ -1,5 +1,5 @@
 <!--
-    Include this file to record all low level comms, so you can playback later on for debugging
+    Include this file to use these utilities to record all low level comms, so you can playback later on for debugging
  -->
 <launch>
     <arg name="prefix" default="record"/>
@@ -22,4 +22,14 @@
     <node if="$(optenv OM_ENABLE_RECORDING_ALL False)" pkg="rosbag" type="record" name="rosbag_record_diag_alle"
           args="record -o /$(env HOME)/all_$(arg prefix) -a" />
 
+    <arg name="snapshot_duration" value="$(optenv OM_SNAPSHOT_DURATION 1200)" />
+    <arg name="snapshot_memory" value="$(optenv OM_SNAPSHOT_MEMORY_PER_TOPIC 0.0)" />
+
+    <node if="$(eval arg('snapshot_duration') > 0 and arg('snapshot_memory') > 0)" name="snapshot" pkg="rosbag_snapshot" type="snapshot" args="" subst_value="true">
+        <param name="default_duration_limit" value="$(arg snapshot_duration)" />  <!-- Maximum time difference between newest and oldest message, seconds, overrides -d flag -->
+        <param name="default_memory_limit" value="$(arg snapshot_memory)" />  <!-- Maximum memory used by messages in each topic's buffer, MB, override -s flag -->
+        <param name="clear_buffer" value="false" />  <!-- No option / true will clear the buffer after writing to bag. False will not clear buffer -->
+        <param name="compression" value="LZ4" />  <!-- LZ4, BZ2, uncompressed -->
+        <param name="record_all_topics" value="true" />
+    </node>
 </launch>

src/open_mower/package.xml

@@ -34,6 +34,7 @@
   <exec_depend>imu_filter_madgwick</exec_depend>
   <exec_depend>twist_mux</exec_depend>
   <exec_depend>rtcm_msgs</exec_depend>
+  <exec_depend>rosbag_snapshot</exec_depend>
 
 
   <!-- The export tag contains other, unspecified, tags -->

utils/scripts/save_snapshot.sh

@@ -0,0 +1,7 @@
+#!/bin/sh
+
+# This script saves a record of all recent low-level ros messages to a ros bag.
+# Usage: ./save_snapshot.sh output_file.bag
+
+
+rosrun rosbag_snapshot snapshot -t -O "$1"