# Copyright (c) 2021 Wind River Systems, Inc.
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
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#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
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latd
---
This is a daemon expected to run inside the LAT container as the entry point.
It accepts requests from clients and issue correspoing commands to generate the image.
Functionalities:
* Accept request to give client an example yaml file to start with
latc getyaml
* Accept build request to build image, with a yaml file supplied.
latc build --file stx.yaml
* Accept request to stop the previous build
latc stop
* Accept request to clean things up, including all build results
latc clean
* Accept status query request, return meaningful contents
latc status
e.g.
lat_status: idle/busy
latest_build_status: running/succeed/fail/not-started
* Accept logs requrest, return log information about the latest build
latc logs
latc(builder container client)
---
A dummy implementation to only show how to make use of volume.py to communicate with latd.
e.g.
latc status/stop/clean/logs/build
volume communication implementation
---
* channel/c-2-s.msg
Client to server message. Convey info about what to do.
action: build/status/stop/logs/clean/getyaml
yaml_file: /mnt/workspace/stx.yaml
* channel/c-2-s.done
A file to watch, when it appears, latd read c-2-s.msg and act accordingly.
* channel/s-2-c.msg
Server to client message. Same format as c-2-s.msg
* channel/s-2-c.done
A file to watch, when it appears, latc reads s-2-c.msg and act accordingly.
* channel/invalid_message
A file which, if exists, indicates the an invalid client request.
* channel/status.lat
File containing LAT container status.
* log/log.appsdk
Hold information about the appsdk debug output.
* client_message_history
Hold message history from client.
* hack/lat-genimage-cmd
A hack file, which replace the 'appsdk genimage ...' command with the contents inside it.
e.g.
echo "sleep 10" > hack/lat-genimage-cmd
This is ONLY for debugging purpose. This mechanism should be removed in formal release.
* latd workflow
Watch c-2-s.done, when it appears, read c-2-s.msg, delete c-2-s.done file.
Fork a subprocess to do the actual work if needed, record its PID; otherwise, perform some action. Send result to client.
Note that the result only means whether the client request is handled by latd or not.
Assumption
---
* At any time, at most one build is run inside LAT container.
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