add information based on jsk-ros-pkg#1706

jsk_robot_common/jsk_robot_startup/lifelog/README.md

@@ -85,3 +85,45 @@ Save object detection result to database
 * `~robot_frame` (String, default: `base_footprint`)
 
   robot base tf frame
+
+
+## Examples
+
+You can start a mongodb logging system using `lifelog/mongodb.launch` and `lifelog/common_logger.launch` files.
+ See [jsk_pr2_lifelog/db_client.launch](https://github.com/jsk-ros-pkg/jsk_robot/blob/5d90d483aaa674d33968f34db83f53cd3d018bd4/jsk_pr2_robot/jsk_pr2_startup/jsk_pr2_lifelog/db_client.launch), [fetch_lifelog.xml](https://github.com/jsk-ros-pkg/jsk_robot/blob/921097b7a9c16cd99d0eb8f9f271bda4784dadc5/jsk_fetch_robot/jsk_fetch_startup/launch/fetch_lifelog.xml) and [jsk_baxter_lifelog/db_client.launch](https://github.com/jsk-ros-pkg/jsk_robot/blob/c03dc5af06d8b7786b4212b132047acaa229eb0e/jsk_baxter_robot/jsk_baxter_startup/jsk_baxter_lifelog/db_client.launch) for examples.
+
+## Sample client
+
+Sample program to retrieve stored data can be found at [jsk_robot_startup/scripts/robot_databse_monogo_example.py](./scripts/robot_databse_monogo_example.py).
+
+To connect replicator server (musca), you need to start [jsk_robot_startup/launch/robot_databse_monogo_server.launch](./launch/robot_databse_monogo_server.launch). Please be careful about `ROS_MASTER_URI`, because `robot_databse_monogo_server.launch` will starts same node name as robot system nodes, thus it may corrupt some settings.
+
+## Troubleshooting
+
+If you encounter following error
+```
+[ERROR] [1666693339.502586]: Could not get message store services. Maybe the message store has not been started? Retrying..
+[ERROR] [1666693339.502586]: Could not get message store services. Maybe the message store has not been started? Retrying..
+```
+
+1) Is mongodb service working correctly?
+```
+sudo systemctl status mongodb.service
+sudo systemctl start mongodb.service
+```
+
+2) Is `mongo` command works?
+```
+mongo localhost:27017
+```
+
+3) Check /etc/mongodb.conf
+```
+$ cat /etc/mongodb.conf | grep -v ^#
+dbpath=/var/lib/mongodb
+logpath=/var/log/mongodb/mongodb.log
+logappend=true
+bind_ip = 0.0.0.0
+journal=true
+```
+Default `bind_jp` is `127.0.0.1`, and it not work on some machines, see [#1706](https://github.com/jsk-ros-pkg/jsk_robot/issues/1706) for more info.