Configuration parsing error: mmap_log_buffer_size

[symstu-tempesta]

Describe the issue
I cannot set the configuration value for mmap_log_buffer_size.

Expected Behavior
Tempesta FW starts correctly but currently crashes when the mmap_log_buffer_size configuration parameter is set.

To Reproduce
Add the following line to your Tempesta configuration and start the application:

mmap_log_buffer_size 4096;

Configuration file

            listen 80;
            server localhost:8000;

            access_log dmesg mmap mmap_host=localhost mmap_log=/tmp/access.log;
            mmap_log_buffer_size 4096;

Version or commit hash
80598c9

Stacktrace or debug log

[23215.774224] Start test: t_clickhouse.test_clickhouse_logs.TestClickhouseLogsBaseTest2.test_missing_log
[23215.933958] [tdb] Start Tempesta DB
[23215.952773] [tempesta fw] Initializing Tempesta FW kernel module...
[23216.038606] [tempesta fw] ERROR: the first character is not a letter: '4'
[23216.038609] [tempesta fw] ERROR: syntax error
[23216.038611] [tempesta fw] ERROR: configuration parsing error:
                  5:             4096;
                     ^^^^^^^^^^^^^^^^^
[23216.038613] [tempesta fw] Warning: Configuration parsing has failed. Clean up...
[23216.086674] [tempesta fw] exiting...
[23216.180309] [tdb] Shutdown Tempesta DB

[EvgeniiMekhanik]

I think we should implement additional configuration file for this daemon (in JSON format) and use boost to parse it. Daemon should be started in two modes as a daemon or in a handle mode for debug purpose

[krizhanovsky]

Please create a new wiki page for tfw_logger and document mmap_log_buffer_size there (we don't have anything about this option in our wiki). The mmap part must be moved from https://tempesta-tech.com/knowledge-base/Handling-clients/ to the new wiki page.

Now access_log must just accept two options, which can be used together: tfw_logger and dmesg. E.g.

access_log dmesg tfw_logger=/path/to/config.json

See #2421 for the configuration changes: make the transition to the separate JSON configuration and leave the ML configuration part for #2421.

Please also rename utils to log or logger - "utils" is to generic and contains the logging daemon only, which is going to grow in the next few issues.