check - path checking helper

This program is providing path checking services for vdsm.

The program is running as a child process, accepting commands on stdin, sending events on stdout, and logging messages on stderr.

Commands

start PATH INTERVAL

Start checking PATH every INTERVAL seconds. A "start" event will be sent as response.
stop PATH

Stop checking PATH. A "stop" event will be sent as a response.

Events

start PATH ERRNO DESCRIPTION

A "start" command completed. On success (ERRNO=0), a "check" event will be sent when the first check completes.
check PATH ERRNO [DELAY|DESCRIPTION]

A check for PATH completed. On success (ERRNO=0), DELAY is the read delay in seconds.
stop PATH ERRNO DESCRIPTION

A "stop" command completed. On success (ERRNO=0), no more "check" events will be sent. If path checker is busy and cannot be stopped immediately , an EINPROGRESS error is returned, and a second event will be sent when io has completed and the path checker has stopped.

Logging

LEVEL message... - log message at LEVEL

The parent process may log the messages using its own logger.

Example session

time   sender  message
---------------------------------------------------
00.000 Client: start /path 10
00.001 Server: start /path 0 started
00.002 Server: check /path 0 0.000542
10.002 Server: check /path 0 0.001023
20.001 Server: check /path 0 0.000981
35.345 Server: check /path 5 Input/output error
40.001 Server: check /path 5 Input/output error
50.001 Server: check /path 5 Input/output error
61.655 Server: check /path 0 1.654321
69.000 Client: stop /path
69.001 Server: stop /path 0 stopped

Hacking

Clone the source from gitlab:

git clone https://gitlab.com/nirs/check.git

Required packages - Fedora

dnf install golang make

Required packages - Debian

apt-get install golang-go make

Required packages - common

pip install -r requirements.txt

Building:

make

Running the tests:

make test

Please open a merge request in gitlab.

Containers

To build the containers locally:

cd containers
make

To run the tests in a container:

podman run \
    -it \
    --rm \
    --volume `pwd`:/src:Z \
    check-fedora-35 \
    bash -c "cd src && make test"