BashCD

Simple cron-friendly polling continuous deployment script.

• Setup
• Variables
• Polling
• Logs
• Locks

• Setup

1. Configure config.sh

# Url of the git repo to be cloned (may contain creds)
export GIT_REPO="<<repo url>>"
# branch to checkout
export GIT_BRANCH="<<branch to poll>>"
# delete logs older that n days
export LOG_RETENTION_DAYS=1
# keep logs of runs that didn't detect change (maybe good for debug)
export KEEP_NOCHANGE_LOGS=false

2. Implement run.sh

Add your custom run.sh implementation, CWD for the script is source code downloaded by poll.sh ($SOURCE_DIR).

run.sh will be ran only when poll.sh determines a change.

Preferably always set -e as the pipeline handles failed scripts gracefully.

3. Test

You must set ENV var WORK_DIR where all intermediate files will be stored. It should be persistent store (not /tmp). Then execute.

WORK_DIR=./cdpipeline ./bashcd.sh

4. CRON

Register tested command as CRON job.

• Variables

BashCD sets some variables for you to use during running of your script run.sh

# contains unique identifier of job instance
$PIPELINE_RUN_ID

# Absolute path of directory containing source code of polled app
$SOURCE_DIR 

# Absolute path to file that contains log for current job instance, always append >> to it. All stdout/stderr of run.sh is redirected there by default.
$LOG_FILE 

# Absolute path to dir where to put built binaries etc...
$ARTIFACT_DIR 

• Polling - poll.sh

By default it contains GIT poller that checks whether there is new HEAD hash in git repo and compares it with previous poll.

poll.sh is expected to download all necessary sources and put them into $SOURCE_DIR and print either "has-changes" or "no-changes".

It should store its current state into $STATE_DIR which is persisted for next runs.

• Logs

All outputs of poll.sh and run.sh are stored into log files that are located at $WORK_DIR/logs. Filename always contains timestamp and result of pipeline e.g. 20210803090340-success.log, 20210803090348-execfailed.log, 20210803090514-nochange.log, 20210803090609-pollfailed.log

Logs are deleted based on $LOG_RETENTION_DAYS.

If $KEEP_NOCHANGE_LOGS is not set to "true" then nochange logs are deleted after run to prevent unnecessary log files.

• Locks

On job startup a lockfile is created that prevents running another same job in parallel. Early bird gets the worm.

License MIT