slackdump wrapper to use in a cron job to download one month of Slack conversations and attachments

getmonth.sh

#!/bin/bash
# using bash for `printf -v` to zero-pad month

# slackdump: https://github.com/rusq/slackdump
# instructions for getting secrets to put in secrets.txt: https://github.com/rusq/slackdump/blob/master/doc/login-manual.rst

# Run it from a directory containing subdirectories named after slack workspaces, each containing a secrets.txt:
# getmonth.sh some-slack-workspace-name lastmonth
# getmonth.sh other-slack-workspace-name 2024 6

set -e

basedir=$(dirname "$0")

workspace=$1
if [ -z "$workspace" ]; then
	echo "Pass slack workspace, then either 'lastmonth' or year and month."
	exit
fi

workspacedir="$basedir/$workspace"
if [ ! -d "$workspacedir" ]; then
	echo "Directory does not exist: $workspacedir"
	exit
fi

if [ ! -f "$workspacedir/secrets.txt" ]; then
	echo "Secrets file does not exist in $workspacedir"
	exit
fi

if [ "$2" = "lastmonth" ]; then
	first_day=$(date -u -d "`date +%Y%m01` -1 month" +%Y-%m-%dT%H:%M:%S)
	last_day=$(date -u +%Y-%m-01T00:00:00)

	# for filename:
	year=$(date -u -d "$first_day" +"%Y")
	month=$(date -u -d "$first_day" +"%m")
else
	year="$2"

	if [ -z "$3" ]; then
		echo "Pass year and month."
		exit
	fi

	# zero-pad month:
	printf -v month "%02d" $3

	first_day=$(date -u -d "`date +${year}${month}01`" +%Y-%m-%dT%H:%M:%S)
	last_day=$(date -u -d "`date +${year}${month}01` +1 month" +%Y-%m-%dT%H:%M:%S)
fi

cachedir="$workspacedir/cache"

pushd "$workspacedir"
slackdump -w "$workspace" -cache-dir "$cachedir" -dump-from $first_day -dump-to $last_day -download -export-type standard -export slackdump-${year}-${month}.zip

popd