CloudflareDDNS/etc/logwatch/README.md

# Using Logwatch to monitor Cloudflare DDNS updater script <!-- omit in toc -->

The Cloudflare DDNS update script's log file has been set up so that utilities
like Logwatch can easily parse it.  In order to make that happen, a LogFile
Group file, Service and Script have to be created for Logwatch to generate
reports.  The correct (general) directory structure has been created in this git
archive already.  Below are the details of each file.

## Contents <!-- omit in toc -->

- [LogFile Group file (/etc/logwatch/conf/logfiles/cfddns.conf)](#logfile-group-file-etclogwatchconflogfilescfddnsconf)
    - [Log file location](#log-file-location)
    - [Archive location and name format](#archive-location-and-name-format)
    - [External script for timestamp processing](#external-script-for-timestamp-processing)
- [Service definition file (/etc/logwatch/conf/services/cfddns.conf)](#service-definition-file-etclogwatchconfservicescfddnsconf)
    - [LogFile Group file definition](#logfile-group-file-definition)
    - [Report title](#report-title)
- [Service script (/etc/logwatch/scripts/services/cfddns)](#service-script-etclogwatchscriptsservicescfddns)
    - [Detail levels](#detail-levels)
- [Timestamp processing script (/etc/logwatch/scripts/shared/sqfullstampanywhere)](#timestamp-processing-script-etclogwatchscriptssharedsqfullstampanywhere)
    - [The time format specification](#the-time-format-specification)
    - [The search REGEX](#the-search-regex)
- [Testing](#testing)
- [Final thoughts](#final-thoughts)

## LogFile Group file (/etc/logwatch/conf/logfiles/cfddns.conf)

### Log file location

Update this as needed to point to the location and name of the log file
generated by the updater script.  Remember, by default, the log file is created
in the same directory as the script itself.

```Ini
LogFile = /path/to/your/cfddns.log
...
```

Best practices suggest you use the *-l*
flag to change this location to something like */var/log/cfddns.log*, for
example.  In that case, the entry would look like:

```Ini
LogFile = /var/log/cfddns.log
...
```

### Archive location and name format

If you want Logwatch to process old (archived) log files generated by something
like *Logrotate*, then you have to specify the location and file name format of
those files.  I've included the generalized compressed format of such rotated
files as the default in the script.  Suppose you store your log files in the
recommended location (*/var/log/*) and are using *Logrotate* with compression
enabled, the archive line would look like:

```Ini
...
Archive = /var/log/cfddns.log.?.gz
...
```

This would tell Logwatch, when the archive option is set to true, that your
*cfddns.log* files are archived as: *cfddns.log.1.gz*, *cfddns.log.2.gz*, etc.
and are all located in */var/log/*.

**Note: This line is totally optional and only used if you set the archive
option in Logwatch to true.  You can comment/delete this line if you wish.**

### External script for timestamp processing

Since the log file uses a non-standard (according to Logwatch) method of
datestamping, a custom filter had to be created.  See the
[relevant](#timestamp-processing-script-etclogwatchscriptssharedsqfullstampanywhere)
section of this document for more information.

The script file is called with an *\** before the filename.

```Ini
...
*sqFullStampAnywhere
...
```

If you change the name of this file, you will have to change this line.
Remember that whatever you type here as a name is converted to all-lowercase
so your filename should be all lowercase also.

## Service definition file (/etc/logwatch/conf/services/cfddns.conf)

### LogFile Group file definition
The service file needs to know what group of log files it is responsible for
processing.  This MUST match the name of your *LogFile Group file*:

```Ini
LogFile = cfddns
...
```

If you change your LogFile Group filename, then update it here too without the
*.conf* extension.

### Report title
The Logwatch output file (html or text) is divided into sections.  You can
define the title to be anything that has meaning for you.  I have arbitrarily
chosen *"CloudFlare DDNS update"* but you can change it to anything you want by
modifying the line:

```Ini
...
Title = "CloudFlare DDNS update"
```

## Service script (/etc/logwatch/scripts/services/cfddns)

Logwatch calls any script with a name that **matches the service name**.  You'll
notice that I just named everything *cfddns* to keep things simple.  You can
change this to whatever you want, however.  If you changed the service name to
*"cloudflare*.conf", for example, you would have to rename this script file to
"*cloudflare*" with no extension.  Note: The script is a PERL file (note the
shebang) but it can be written in any language.

In essence, Logwatch just spits out the log file(s) defined in the LogFile Group
file as standard input (STDIN) for the script and then takes whatever is output
(STDOUT) from the script to assemble into it's report.

### Detail levels

The script supports four (4) detail levels as follows:

-  **Level 0: Summary output only**
    -  This will display an aggregate total of certain logged elements.  It will
       display the total number of hostnames (A and AAAA) that are already
       up-to-date, those that needed updating, those successfully updated and
       the total number of errors (of any type) encountered by the script.  All
       totals are relative to the reporting period Logwatch is using (--range
       parameter).

       **This is the recommended reporting level.**  It does not
       take up much space and is quick to read.  If you see successful updates
       match the number of needed updates and no errors logged, then things are
       working properly.  If you notice errors, you should consult the full
       logs.
-  **Levels 1-4: Critical messages**
    -  This uses the data which is summarized by Level 0 but outputs the actual
       messages in the log file.  For example, you will see the actual text of
       the errors logged instead of just a total number of errors.  This level
       of reporting is useful when *initially* monitoring the script's
       operation since you can see the actual text of any generated errors.
-  **Level 5: Verbose (debugging) output**
    -  Like the previous level, this outputs the actual messages found in the
       log file.  However, it also includes *[INFO] tags* which contain logged
       messages such as the detected IP address and the specific names of any
       hostnames not found in your Cloudflare account, etc.  This level of
       reporting is useful in diagnosing why errors are occurring or if you just
       want more insight into how the script works.
       
       **This level of output will
       make your Logwatch reports longer and consume more of your time to
       review. You should not use this level day-to-day.**
- **Levels 6+: Complete log file dump**
    -  Any number greater than 5 passed as a detail level will trigger the
       script to dump the entire log file out to Logwatch line-by-line.  This is
       useful only if you are debugging an issue and cannot get access to the
       actual raw log file itself.  The actual log file is colour-coded which
       makes it much easier to read for debugging purposes.
       
       **Use this detail level only when you need
       to see the entire log file and cannot otherwise access the log file.**

## Timestamp processing script (/etc/logwatch/scripts/shared/sqfullstampanywhere)

This is basically a modified version of the '*applyeurodate*' script that comes
with Logwatch.  It had to be modified to search within [square brackets] and to
accept characters coming before the stamp (i.e. ANSI colour codes).  If you
change the '**stamp**' variable in the updater script to update the timestamp to
your liking (which to totally fine!) then you'll probably have to update this
file.  There are two lines you need to modify to suit your new '**stamp**'
variable.

### The time format specification

'*$SearchDate*' is the variable used in the PERL script to do exactly what it
says, search for the date stamp.  I have it set up to look for the format
'*year-month-date hour:minute:second*'.  Note, we don't care about brackets or
anything here, we're just defining the format of the date/time stamp.

```Perl
...
$SearchDate = TimeFilter('%Y-%m-%d %H:%M:%S');
...
```

If you changed the '**stamp**' variable so it was formatted as '*month/day/year
hour:minute*' (ex: '*[09/27/2018 18:38]*') then you'd update the **$SearchDate**
variable as follows (note: no mention of the square brackets!):

```Perl
...
$SearchDate = TimeFilter('%m/%d/%Y %H:%M');
...
```

### The search REGEX

The PERL script uses a '*regular expression*' (REGEX) to search within the log file for
'*$SearchDate*'.  For the default datestamp, this specification looks like:

```Perl
...
if ($ThisLine =~ m/\[$SearchDate\] /o) {
...
```

The REGEX appears between '*m/*' and '*/o*'.  In this case, it searches for
'*$SearchDate*' inside [square brackets] appearing anywhere on the line.  This
is because ANSI colour-codes often appear before the datestamp in the default
log file.  If you have modified this so that your datestamp appears at the
beginning of the line and in the example format in the section above (using
slashes instead of dashes) then you'd rewrite this REGEX as follows:

```Perl
...
if ($ThisLine =~ m/^\[$SearchDate\] /o) {
...
```

or using regular brackets anywhere on the line:

```Perl
...
if ($ThisLine =~ m/\($SearchDate\) /o) {
...
```

or without any brackets but appearing at the beginning of the line:

```Perl
...
if ($ThisLine =~ m/^$SearchDate /o) {
...
```

## Testing

Run *logwatch --help* and note the options.  You can test just this service
locally on your screen with the following command (assuming you kept default
names for everything):

```Bash
# Summary output, entire duration of log file
logwatch --service cfddns --output stdout --format text --range all --detail 0

# Minimal detail, yesterday only
logwatch --service cfddns --output stdout --format text --range yesterday --detail 3

# Verbose output, today only
logwatch --service cfddns --output stdout --format text --range today --detail 5
```

## Final thoughts

That's it!  I'm a horrible PERL programmer so if anyone can optimize/improve the
script file used for Logwatch then please do it!  Otherwise, I hope this made
sense and helped you integrate the updater script with Logwatch for easy
monitoring :-)