WEBVTT 00:04.910 --> 00:10.920 Engine X provides us two log types error logs and access logs a log. 00:10.970 --> 00:17.720 As the name suggests for anything that failed or didn't happen as expected and access logs to log all 00:17.720 --> 00:19.800 requests to the server. 00:19.970 --> 00:26.060 Logging is an extremely important aspect of not only in generics but web servers in general as logs 00:26.060 --> 00:30.330 allow us to track down errors or even identify malicious users. 00:30.380 --> 00:32.570 Logging has also enabled by default. 00:32.600 --> 00:39.200 So for that reason most of the time leaving the lock configuration as is will be fine but understanding 00:39.200 --> 00:45.830 how to change them is definitely important and disabling logs for certain conditions or creating resource 00:45.830 --> 00:51.570 specific logs can both help lower resource usage and improve the log file structure. 00:51.620 --> 00:56.990 In our case we said the path to the log files when we configured in generics in the installation section 00:56.990 --> 01:02.700 of the course which was slash var slash log slash engine X.. 01:03.570 --> 01:06.260 And if we list the contents of that directory. 01:07.040 --> 01:14.000 We see those two log files error log and accessed log with both files already containing several entries 01:14.030 --> 01:17.970 from throughout this course as we can see from the file sizes. 01:18.410 --> 01:20.960 I'll change into that logs directory. 01:21.760 --> 01:27.990 And clear both of these log files so we can start from scratch just echo an empty string to access dot 01:27.990 --> 01:28.880 log. 01:29.020 --> 01:31.090 And same for error dot log. 01:31.120 --> 01:31.680 Done. 01:33.460 --> 01:40.730 Then to see a default access log entry head over to the browser and request slash a thumb dot PRNG. 01:41.650 --> 01:42.580 That loads. 01:42.610 --> 01:44.470 So check the access log. 01:45.520 --> 01:48.840 And there we have it for thumb dot PRNG. 01:49.150 --> 01:55.810 Now a very common misconception is that forro fours get logged in the error log which most of the time 01:55.870 --> 01:57.550 is not the case. 01:57.550 --> 02:04.290 First let's reset this configuration back to serving the demo site without any rewrites save that. 02:06.750 --> 02:07.840 Reload. 02:08.700 --> 02:16.590 And again in the browser I'll request a u r l that does not exist say slash missing which gives us that 02:16.590 --> 02:18.970 standard engine X for a 4. 02:19.080 --> 02:20.410 Check the access log. 02:21.190 --> 02:22.330 And there we have it. 02:22.420 --> 02:25.310 That request with a status of four of four. 02:25.330 --> 02:32.710 Now I say not always as a properly handled foro for won't produce an error blog entry but in our case 02:33.070 --> 02:36.940 log that out engine X could not match a file to the request. 02:36.940 --> 02:37.630 You are right. 02:37.750 --> 02:39.470 And resulted in an error. 02:39.520 --> 02:44.920 Just something to keep in mind for a form is a perfectly valid response and by no means an error in 02:44.920 --> 02:52.490 itself to create a typical entry in the error log then will have to cause engine X to actually malfunction. 02:52.510 --> 02:58.990 For example I'll add a second argument to the root directive which only expects a single argument save 02:58.990 --> 03:02.430 this attempt to reload the configuration. 03:03.840 --> 03:11.130 Which has of course silently failed but in there a log we have that error entry invalid number of arguments 03:11.190 --> 03:16.360 in root directive with a reference to the line in the configuration file. 03:16.440 --> 03:22.770 We can also create custom log files or disable logging all together for a given context by means of 03:22.770 --> 03:27.350 the access underscore log or error underscore log directives. 03:27.390 --> 03:32.590 For example let's say we want to add an exit log for all requests to slash secure. 03:32.850 --> 03:38.810 I'll create a location context for that you are by returning a simple string. 03:39.150 --> 03:41.470 Welcome to secure area. 03:41.760 --> 03:50.400 And in here enable an access log by saying access underscore log with a path to that log file var log 03:50.490 --> 03:58.470 slash engine X. secure dot access dot log keeping it in that engine log directory save. 03:59.710 --> 04:07.390 Reload the configuration and immediately if we list the contents of our log in generics that file has 04:07.390 --> 04:10.900 already been created ready to log requests. 04:11.780 --> 04:13.980 Navigate to slash secure. 04:15.110 --> 04:16.420 We get the message. 04:16.430 --> 04:18.230 So check the access log. 04:19.100 --> 04:20.450 And there it is. 04:20.480 --> 04:26.660 Whilst no longer existing in the global access log it is possible to log this to both However by simply 04:26.660 --> 04:29.520 adding another access log with the global path. 04:29.690 --> 04:35.330 In which case we'll get that log entry and both log directives being one of the few directives you can 04:35.330 --> 04:41.180 use multiple times like this but will cover directive types in more detail in the next lesson. 04:41.180 --> 04:47.360 Another common use of the log directive is to disable logging for certain requests and in doing so reducing 04:47.360 --> 04:53.660 server load and keeping log files smaller particularly useful for sites receiving very high traffic 04:54.320 --> 05:00.730 to disable logging for a given context then it's as simple as saying access underscore log off. 05:01.460 --> 05:08.060 Generally I'd say disable the majority of access logs and leave error logging in place but this will 05:08.060 --> 05:14.210 depend on individual server requirements for more advanced logging configurations we can also specify 05:14.210 --> 05:20.620 the access log format enabled Jesus being of the log file or set the log level for error logs. 05:20.780 --> 05:25.000 But again that's typically for larger more advanced configurations. 05:25.070 --> 05:29.150 I've linked to a very good engine XT dot.com article in the LIS and resources. 05:29.240 --> 05:32.930 Should you be interested in these advanced options in the next lesson. 05:32.930 --> 05:37.770 We'll take a look at those different DirecTV types and the basics of inheritance.