Where is apache log file

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GIT Guide. Linux Guide. Spring Framework. Learn C Language. Core Java. Computer Science. What are Deadlocks? MongoDB vs. Interactive Courses, where you Learn by doing. Available for FREE! As any developer or system administrator will tell you, log files are an extremely useful tool for debugging issues within a web application.

In fact, log files are typically utilized as the primary source of information when a website is malfunctioning. One specific log file that can be used in debugging applications or simply gaining insight into visitor activity is the access log produced by an Apache HTTP server.

Since the real power of log data comes from comprehending the meaning of the data through analysis, I will also discuss the benefits of working with a log management and analytics platform such as Sumo Logic to derive valuable insights from access log data.

This particular log file is responsible for recording data for all requests processed by the Apache server. So if an individual visits a webpage on your site, the access log file will contain details regarding this event.

This information is valuable in a variety of situations: for example, if a common request is failing for each individual trying to get to a particular web page, the link may be pointing to a page that no longer exists; if a certain page on the site is taking longer than it should to load, log entries could indicate SQL queries that could be refactored to improve performance; if one particular page on the site is very popular, aggregating data from access logs could shine a light on commonly requested resources, thus enabling businesses to increase their popularity by providing more related content.

So, for the purposes of this article, we will stick to detailing where the Apache access logs can be found on a Linux machine. On the Ubuntu Linux distribution, for example, access log records will be written to the following location by default:.

The default location may vary slightly on other Linux distributions, but you will not have to look very far in most cases.

Ultimately, the location and format more on this later of the access logs are defined by a CustomLog directive which can be viewed and modified within your Apache HTTP server configuration. Now that you know what Apache access logs are and where they can be found, we can explain how to interpret the entries so that your development team and other IT personnel can make good use of them.

Making sense of the Apache access logs requires that the analyst understand the format in which the access logs are being recorded. As mentioned above, the format for the access logs is defined in the CustomLog directive along with the location.

We will take a look at two popular log formats that are often utilized with Apache access logs below. The Common Log Format is a standardized text file format used by various web servers in generating server log files. With an Apache HTTP server, the Common Log Format can be used to produce access logs that are straightforward enough for developers and administrators to read.

In addition, as it is a standardized format in use by multiple web servers, CLF-formatted log files can be easily used by many log analysis platforms. Another format that is often used with Apache access logs is the Combined Log Format. This format is very similar to the Common Log Format but contains a few extra fields to provide more information for use in analysis and debugging operations. An access log record that is recorded in the Combined Log Format looks something like this:.

As you can see, the first seven fields are identical to those in Common Log Format. The context containers include: main apache config, vhost config, within directory tags, and.

This module is provided by default in many of the package distributions, but may require enabling. For the purposes of logging, the FilterTrace directive posts information to the error log. Directives include:. The following example applies filtering in a vhost context container conditionally on filter and include modules:. This module constructs an environment variable and a unique identifier for each request.

This unique identifier is written to the access log. This allows application developers to trace a request through the web server to the application server. It can be useful for debugging a request. Apache spins off child processes to handle requests, and a child instance processes several requests at a time. As a result, it is sometimes desirable to use a unique identifier to identify a single request across multiple server instances and child processes. The identifier is constructed from a bit IP address, bit process ID, bit timestamp coupled to a bit counter for tighter resolution than a single-second, bit thread index.

The timestamp component is UTC to prevent issues with daylight savings time adjustments. The application handler should treat the identifier as an opaque token only and not dissected into constituents.

LOG IN. Ultimate Guide to Logging Your open-source resource for understanding, analyzing, and troubleshooting system logs. NET Logging Basics. NET Logging Libraries. NET Searching Logs. NET Troubleshooting and Analyzing. Apache Logging Basics The Apache log records events that were handled by the Apache web server including requests from other computers, responses sent by Apache, and actions internal to the Apache server.

Types of Apache Logs Apache generates two kinds of logs: access logs and error logs. Access Log The access log contains information about requests coming in to the web server. Here is an example of a typical access log entry: Here is an example error log: [Thu Mar 13 ] [error] [client Log Level Directive The LogLevel directive determines the minimum s everity level of events that are logged to a specific destination.

Log Format The LogFormat directive controls the layout and formatting of log events. This is useful for identifying traffic from a particular source. This is useful for measuring the speed of your site. This is useful for tracing a request from Apache to your web application server. Assigning Nicknames LogFormat strings can be assigned nicknames, which you can then use with a CustomLog directive to write logs using the specified format.