Script - log to text file

@jameson

A little brute force, but I use the following when I want all output in a log: set -xv; exec 1> $LOGFILE 2>&1 The variable $LOGFILE points to whatever log file I want to save to.

Showing the running command in a bash script with "set -x"

The exec 1>$LOGFILE 2>&1 bit redirects stdout (1) to the logfile and stderr (2) to stdout.

You should build a logger, and then code logic and error handling in it to send data to a log file

zsh example:

#!/bin/zsh

# example log function

LOGFILE="/var/log/mylog.log"

logger() {
    echo $(date "+%Y-%m-%d %H:%M:%S ") $1 >> "${LOGFILE}"
}


logger "this is a test of the emergency broadcast system"
logger "[ERROR] non zero exit status has occurred..."
logger "[WARN] non standard config detected..."

output:

% sudo zsh -x logger.sh 
+logger.sh:5> LOGFILE=/var/log/mylog.log 
+logger.sh:12> logger 'this is a test of the emergency broadcast system'
+logger:1> date '+%Y-%m-%d %H:%M:%S '
+logger:1> echo 2019-10-16 10:49:05 'this is a test of the emergency broadcast system'
+logger.sh:13> logger '[ERROR] non zero exit status has occurred...'
+logger:1> date '+%Y-%m-%d %H:%M:%S '
+logger:1> echo 2019-10-16 10:49:05 '[ERROR] non zero exit status has occurred...'
+logger.sh:14> logger '[WARN] non standard config detected...'
+logger:1> date '+%Y-%m-%d %H:%M:%S '
+logger:1> echo 2019-10-16 10:49:05 '[WARN] non standard config detected...'

The log file:

% cat /var/log/mylog.log
2019-10-16 10:46:49 this is a test of the emergency broadcast system
2019-10-16 10:49:05 this is a test of the emergency broadcast system
2019-10-16 10:49:05 [ERROR] non zero exit status has occurred...
2019-10-16 10:49:05 [WARN] non standard config detected...

Python Example:

# function that contains logging info
def run_jamf_policy(run_list):
    """run through all jamf policies that need to be done"""
    write_to_dnlog("Status: Installing software...")
    number_of_policies = len(run_list)
    write_to_dnlog("Command: DeterminateManual: %s" % number_of_policies)
    for index, policy in enumerate(run_list, 1):
        # get the vanity name from the MAIN_POLICY_DICT
        name = MAIN_POLICY_DICT[policy]
        write_to_dnlog("Status: Deploying %s" % name)
        write_to_dnlog("Command: DeterminateManualStep:")
        logging.info("starting %s policy..." % policy)
        cmd = ["jamf", "policy", "-event", str(policy)]
        proc = subprocess.Popen(cmd, stdout=subprocess.PIPE, stderr=subprocess.PIPE)
        out, errors = proc.communicate()
        if proc.returncode != 0:
            error_msg = "%s code %s" % (errors.strip(), proc.returncode)
            logging.error("jamf binary failed to install %s, %s", policy, error_msg)
            write_to_dnlog("Status: %s policy failed, please see logs..." % policy)
        elif proc.returncode == 0:
            logging.info("jamf policy %s returned successful.." % policy)
            write_to_dnlog("Status: %s was successfully installed..." % name)
    write_to_dnlog("Command: DeterminateOff:")
    write_to_dnlog("Command: DeterminateOffReset:")

# function to write to the DEP Notify log
def write_to_dnlog(text):
    """function to modify the DEP log and send it commands"""
    depnotify = "/private/var/tmp/depnotify.log"
    with open(depnotify, "a+") as log:
        log.write(text + "
")

You definitely want to build logic around your logging and check exit status and capture things like stderr