Set of logging helper functions that simplifies bash logging. Session ID helps to identify log rows that belong to same session and allows multiple scripts to use same logfile.

logging_utils.sh

# For OSX https://unix.stackexchange.com/questions/141420/tr-complains-of-illegal-byte-sequence
export LC_ALL=C;
# https://gist.github.com/earthgecko/3089509
INTERNAL_SESSION_ID="$(cat /dev/urandom | tr -dc 'a-zA-Z0-9' | fold -w 8 | head -n 1)"

function get_session_id() {
	echo "$INTERNAL_SESSION_ID"
}

function get_logdate() {
	echo "$(date '+%Y-%m-%dT%H:%M:%S')"
}

# When "logging_utils.sh" is sourced in to another script $0 will contain name of that script, not "logging_utils.sh"
function get_script_name() {
	echo "$(basename $0)"
}

# Arguments:
# $1 - log level
# $2 - log message
# $3 - echo arguments
function log() {
	echo "$3" "$(get_logdate) $1 - $(get_session_id) $(get_script_name): $2"
}

# Arguments:
# $1 Log message
# $2 echo arguments
function log_debug() {
	log "DEBUG" "$1" "$2"
}

# Arguments:
# $1 Log message
# $2 echo arguments
function log_info() {
	log "INFO" "$1" "$2"
}

# Arguments:
# $1 Log message
# $2 echo arguments
function log_warn() {
	log "WARN" "$1" "$2"
}

# Arguments:
# $1 Log message
# $2 echo arguments
function log_error() {
	log "ERROR" "$1" "$2"
}