[#457] Inform the user of misconfigured log_level debug value

If the user set the `log_level = debugX` with X being a number outside
of the valid range 1-5, the application adjusts the logging level to
the upper or lower boundary, now informing the user that her
configuration has been ignored.

Documentation updated.

Also adds `trace` as a synonim for `debug5`.

Close #457

doc/CONFIGURATION.md

@@ -51,7 +51,7 @@ The available keys and their accepted values are reported in the table below.
 | metrics_cache_max_size | 256k | String | No | The maximum amount of data to keep in cache when serving Prometheus responses. Changes require restart. This parameter determines the size of memory allocated for the cache even if `metrics_cache_max_age` or `metrics` are disabled. Its value, however, is taken into account only if `metrics_cache_max_age` is set to a non-zero value. Supports suffixes: 'B' (bytes), the default if omitted, 'K' or 'KB' (kilobytes), 'M' or 'MB' (megabytes), 'G' or 'GB' (gigabytes).|
 | management | 0 | Int | No | The remote management port (disable = 0) |
 | log_type | console | String | No | The logging type (console, file, syslog) |
-| log_level | info | String | No | The logging level, any of the (case insensitive) strings `FATAL`, `ERROR`, `WARN`, `INFO` and `DEBUG` (that can be more specific as `DEBUG1` thru `DEBUG5`). Debug level greater than 5 will be set to `DEBUG5`. Not recognized values will make the log_level be `INFO` |
+| log_level | info | String | No | The logging level, any of the (case insensitive) strings `FATAL`, `ERROR`, `WARN`, `INFO`, `DEBUG` and `TRACE`. The `DEBUG` keyword can be more specific such as `DEBUG1` up to `DEBUG5`; higher numbers mean higher verbosity. Debug level greater than 5 will be set to `DEBUG5`, while levels lower than 1 will be set to `DEBUG1`, and the application will raise a warning about the ignored value. The word `TRACE` is a synonim for `DEBUG5`. Not recognized values will make the log_level be `INFO` |
 | log_path | pgagroal.log | String | No | The log file location. Can be a strftime(3) compatible string. |
 | log_rotation_age | 0 | String | No | The age that will trigger a log file rotation. If expressed as a positive number, is managed as seconds. Supports suffixes: 'S' (seconds, the default), 'M' (minutes), 'H' (hours), 'D' (days), 'W' (weeks). A value of `0` disables. |
 | log_rotation_size | 0 | String | No | The size of the log file that will trigger a log rotation. Supports suffixes: 'B' (bytes), the default if omitted, 'K' or 'KB' (kilobytes), 'M' or 'MB' (megabytes), 'G' or 'GB' (gigabytes). A value of `0` (with or without suffix) disables. |

src/libpgagroal/configuration.c

@@ -2246,6 +2246,12 @@ as_logging_level(char* str)
          free(debug_value);
       }
 
+      if (debug_level < 1 || debug_level > 5)
+      {
+         warnx("Log level debug configuration %d not understood: %s - resetting to none", debug_level, str);
+         debug_level = 1;
+      }
+
       if (debug_level <= 1)
       {
          return PGAGROAL_LOGGING_LEVEL_DEBUG1;
@@ -2288,6 +2294,12 @@ as_logging_level(char* str)
       return PGAGROAL_LOGGING_LEVEL_FATAL;
    }
 
+   // "trace" is a synonim for "debug5"
+   if (!strcasecmp(str, "trace"))
+   {
+      return PGAGROAL_LOGGING_LEVEL_DEBUG5;
+   }
+
    return PGAGROAL_LOGGING_LEVEL_INFO;
 }