In
computing
Computing is any goal-oriented activity requiring, benefiting from, or creating computing machinery. It includes the study and experimentation of algorithmic processes, and development of both hardware and software. Computing has scientific, e ...
, logging is the act of keeping a
log
Log most often refers to:
* Trunk (botany), the stem and main wooden axis of a tree, called logs when cut
** Logging, cutting down trees for logs
** Firewood, logs used for fuel
** Lumber or timber, converted from wood logs
* Logarithm, in mathe ...
of
events
Event may refer to:
Gatherings of people
* Ceremony, an event of ritual significance, performed on a special occasion
* Convention (meeting), a gathering of individuals engaged in some common interest
* Event management, the organization of ev ...
that occur in a computer system, such as problems, errors or just information on current operations. These events may occur in the
operating system
An operating system (OS) is system software that manages computer hardware, software resources, and provides common services for computer programs.
Time-sharing operating systems schedule tasks for efficient use of the system and may also in ...
or in other
software
Software is a set of computer programs and associated documentation and data. This is in contrast to hardware, from which the system is built and which actually performs the work.
At the lowest programming level, executable code consists ...
. A message or log entry is recorded for each such event. These log messages can then be used to monitor and understand the operation of the system, to
debug problems, or during an
audit
An audit is an "independent examination of financial information of any entity, whether profit oriented or not, irrespective of its size or legal form when such an examination is conducted with a view to express an opinion thereon.” Auditing ...
. Logging is particularly important in
multi-user software
Multi-user software is computer software that allows access by multiple users of a computer. Time-sharing systems are multi-user systems. Most batch processing systems for mainframe computers may also be considered "multi-user", to avoid leaving t ...
, to have a central overview of the operation of the system.
In the simplest case, messages are written to a file, called a log file. Alternatively, the messages may be written to a dedicated logging system or to a
log management
Log management (LM) comprises an approach to dealing with large volumes of computer-generated log messages (also known as audit records, audit trails, event-logs, etc.).
Log management generally covers:
* Log collection
* Centralized log agg ...
software, where it is stored in a database or on a different computer system.
Specifically, a transaction log is a log of the communications between a system and the users of that system, or a data collection method that automatically captures the type, content, or time of transactions made by a person from a terminal with that system. For Web searching, a transaction log is an electronic record of interactions that have occurred during a searching episode between a Web search engine and users searching for information on that Web search engine.
Many operating systems, software frameworks and programs include a logging system. A widely used logging standard is
Syslog
In computing, syslog is a standard for message logging. It allows separation of the software that generates messages, the system that stores them, and the software that reports and analyzes them. Each message is labeled with a facility code, i ...
, defined in Internet Engineering Task Force (IETF)
RFC
RFC may refer to:
Computing
* Request for Comments, a memorandum on Internet standards
* Request for change, change management
* Remote Function Call, in SAP computer systems
* Rhye's and Fall of Civilization, a modification for Sid Meier's Civ ...
5424). The Syslog standard enables a dedicated, standardized subsystem to generate, filter, record, and analyze log messages. This relieves software developers of having to design and code their ad hoc logging systems.
Event logs
Event logs record events taking place in the execution of a system in order to provide an
audit trail
An audit trail (also called audit log) is a security-relevant chronological record, set of records, and/or destination and source of records that provide documentary evidence of the sequence of activities that have affected at any time a specific ...
that can be used to understand the activity of the system and to diagnose problems. They are essential to understand the activities of complex systems, particularly in the case of applications with little user interaction (such as
server
Server may refer to:
Computing
*Server (computing), a computer program or a device that provides functionality for other programs or devices, called clients
Role
* Waiting staff, those who work at a restaurant or a bar attending customers and su ...
applications).
It can also be useful to combine log file entries from multiple sources. This approach, in combination with
statistical analysis
Statistical inference is the process of using data analysis to infer properties of an underlying distribution of probability.Upton, G., Cook, I. (2008) ''Oxford Dictionary of Statistics'', OUP. . Inferential statistical analysis infers propertie ...
, may yield
correlations
In statistics, correlation or dependence is any statistical relationship, whether causal or not, between two random variables or bivariate data. Although in the broadest sense, "correlation" may indicate any type of association, in statistics ...
between seemingly unrelated events on different servers. Other solutions employ network-wide querying and
report
A report is a document that presents information in an organized format for a specific audience and purpose. Although summaries of reports may be delivered orally, complete reports are almost always in the form of written documents. Usage
In ...
ing.
Transaction logs
Most
database systems
In computing, a database is an organized collection of data stored and accessed electronically. Small databases can be stored on a file system, while large databases are hosted on computer clusters or cloud storage. The design of databases span ...
maintain some kind of transaction log, which are not mainly intended as an audit trail for later analysis, and are not intended to be
human-readable
A human-readable medium or human-readable format is any encoding of data or information that can be naturally read by humans.
In computing, ''human-readable'' data is often encoded as ASCII or Unicode text, rather than as binary data. In most c ...
. These logs record changes to the stored data to allow the database to recover from
crashes or other data errors and maintain the stored data in a consistent state. Thus, database systems usually have both general event logs and transaction logs.
Transaction log analysis
The use of data stored in transaction logs of Web search engines, Intranets, and Web sites can provide valuable insight into understanding the information-searching process of online searchers. This understanding can enlighten information system design, interface development, and devising the information architecture for content collections.
Message logs
Internet Relay Chat (IRC),
instant messaging (IM) programs,
peer-to-peer
Peer-to-peer (P2P) computing or networking is a distributed application architecture that partitions tasks or workloads between peers. Peers are equally privileged, equipotent participants in the network. They are said to form a peer-to-peer n ...
file sharing clients with chat functions, and
multiplayer
A multiplayer video game is a video game in which more than one person can play in the same game environment at the same time, either locally on the same computing system (couch co-op), on different computing systems via a local area network, or ...
games (especially
MMORPG
A massively multiplayer online role-playing game (MMORPG) is a video game that combines aspects of a role-playing video game and a massively multiplayer online game.
As in role-playing games (RPGs), the player assumes the role of a Player charac ...
s) commonly have the ability to automatically save textual communication, both public (IRC channel/IM conference/MMO public/party chat messages) and private chat between users, as message logs.
Message logs are almost universally plain text files, but IM and
VoIP
Voice over Internet Protocol (VoIP), also called IP telephony, is a method and group of technologies for the delivery of voice communications and multimedia sessions over Internet Protocol (IP) networks, such as the Internet. The terms Internet t ...
clients (which support textual chat, e.g. Skype) might save them in
HTML
The HyperText Markup Language or HTML is the standard markup language for documents designed to be displayed in a web browser. It can be assisted by technologies such as Cascading Style Sheets (CSS) and scripting languages such as JavaScri ...
files or in a custom format to ease reading or enable
encryption
In cryptography, encryption is the process of encoding information. This process converts the original representation of the information, known as plaintext, into an alternative form known as ciphertext. Ideally, only authorized parties can decip ...
.
Internet Relay Chat (IRC)
In the case of IRC software, message logs often include system/server messages and entries related to channel and user changes (e.g. topic change, user joins/exits/
kicks
A kick is a physical Strike (attack), strike using the leg, in unison usually with an area of the knee or lower using the foot, heel, tibia (shin), ball of the foot, blade of the foot, toes or knee (the latter is also known as a knee (strike), ...
/
bans,
nickname
A nickname is a substitute for the proper name of a familiar person, place or thing. Commonly used to express affection, a form of endearment, and sometimes amusement, it can also be used to express defamation of character. As a concept, it is ...
changes, the user status changes), making them more like a combined message/event log of the channel in question, but such a log isn't comparable to a true IRC server event log, because it only records user-visible events for the time frame the user spent being connected to a certain channel.
Instant messaging
Instant messaging and VoIP clients often offer the chance to store encrypted logs to enhance the user's privacy. These logs require a password to be decrypted and viewed, and they are often handled by their respective writing application. Some privacy focused messaging services, such as
Signal
In signal processing, a signal is a function that conveys information about a phenomenon. Any quantity that can vary over space or time can be used as a signal to share messages between observers. The ''IEEE Transactions on Signal Processing'' ...
, record minimal logs about users, limiting their information to connection times.
Server log
![Apache Log](https://upload.wikimedia.org/wikipedia/commons/c/ca/Apache_Log.png)
A server log is a log file (or several files) automatically created and maintained by a
server
Server may refer to:
Computing
*Server (computing), a computer program or a device that provides functionality for other programs or devices, called clients
Role
* Waiting staff, those who work at a restaurant or a bar attending customers and su ...
consisting of a list of activities it performed.
A typical example is a
web server
A web server is computer software and underlying hardware that accepts requests via HTTP (the network protocol created to distribute web content) or its secure variant HTTPS. A user agent, commonly a web browser or web crawler, initiate ...
log which maintains a history of page requests. The
W3C
The World Wide Web Consortium (W3C) is the main international standards organization for the World Wide Web. Founded in 1994 and led by Tim Berners-Lee, the consortium is made up of member organizations that maintain full-time staff working to ...
maintains a standard format (the
Common Log Format
For computer log management, the Common Log Format, also known as the NCSA Common log format, (after NCSA HTTPd) is a standardized text file format used by web servers when generating server log files. Because the format is standardized, the ...
) for web server log files, but other proprietary formats exist.
Some servers can log information to computer readable formats (such as
JSON
JSON (JavaScript Object Notation, pronounced ; also ) is an open standard file format and data interchange format that uses human-readable text to store and transmit data objects consisting of attribute–value pairs and arrays (or other ser ...
) versus the human readable standard.
More recent entries are typically appended to the end of the file. Information about the request, including
client
Client(s) or The Client may refer to:
* Client (business)
* Client (computing), hardware or software that accesses a remote service on another computer
* Customer or client, a recipient of goods or services in return for monetary or other valuabl ...
IP address
An Internet Protocol address (IP address) is a numerical label such as that is connected to a computer network that uses the Internet Protocol for communication.. Updated by . An IP address serves two main functions: network interface ident ...
, request
date
Date or dates may refer to:
*Date (fruit), the fruit of the date palm (''Phoenix dactylifera'')
Social activity
*Dating, a form of courtship involving social activity, with the aim of assessing a potential partner
** Group dating
*Play date, a ...
/
time
Time is the continued sequence of existence and events that occurs in an apparently irreversible succession from the past, through the present, into the future. It is a component quantity of various measurements used to sequence events, to ...
,
page
Page most commonly refers to:
* Page (paper), one side of a leaf of paper, as in a book
Page, PAGE, pages, or paging may also refer to:
Roles
* Page (assistance occupation), a professional occupation
* Page (servant), traditionally a young m ...
requested,
HTTP
The Hypertext Transfer Protocol (HTTP) is an application layer protocol in the Internet protocol suite model for distributed, collaborative, hypermedia information systems. HTTP is the foundation of data communication for the World Wide Web, ...
code, bytes served,
user agent
In computing, a user agent is any software, acting on behalf of a user, which "retrieves, renders and facilitates end-user interaction with Web content". A user agent is therefore a special kind of software agent.
Some prominent examples of us ...
, and
referrer
In HTTP, "" (a misspelling of Referrer) is an optional HTTP header field that identifies the address of the web page (i.e., the URI or IRI), from which the resource has been requested. By checking the referrer, the server providing the new web ...
are typically added. This data can be combined into a single file, or separated into distinct logs, such as an access log,
error
An error (from the Latin ''error'', meaning "wandering") is an action which is inaccurate or incorrect. In some usages, an error is synonymous with a mistake. The etymology derives from the Latin term 'errare', meaning 'to stray'.
In statistics ...
log, or referrer log. However, server logs typically do not collect user-specific information.
These files are usually not accessible to general Internet users, only to the
webmaster
A webmaster is a person responsible for maintaining one or more websites. The title may refer to web architects, web developers, site authors, website administrators, website owners, website coordinators, or website publishers.
The duties of ...
or other administrative person of an Internet service. A statistical analysis of the server log may be used to examine traffic patterns by time of day, day of week, referrer, or user agent. Efficient web site administration, adequate hosting resources and the fine tuning of sales efforts can be aided by analysis of the web server logs.
See also
*
Common Log Format
For computer log management, the Common Log Format, also known as the NCSA Common log format, (after NCSA HTTPd) is a standardized text file format used by web servers when generating server log files. Because the format is standardized, the ...
*
Digital traces
Digital footprint or digital shadow refers to one's unique set of traceable digital activities, actions, contributions and communications manifested on the Internet or digital devices. Digital footprints can be classified as either passive or ...
*
Event Viewer
Event Viewer is a component of Microsoft's Windows NT operating system that lets administrators and users view the event logs on a local or remote machine. Applications and operating-system components can use this centralized log service to repo ...
*
Java Logging Frameworks
A Java logging framework is a computer data logging package for the Java platform. This article covers general purpose logging frameworks.
Logging refers to the recording of activity by an application and is a common issue for development teams. ...
– logging frameworks for
Java
Java (; id, Jawa, ; jv, ꦗꦮ; su, ) is one of the Greater Sunda Islands in Indonesia. It is bordered by the Indian Ocean to the south and the Java Sea to the north. With a population of 151.6 million people, Java is the world's List ...
* .NET Logging Frameworks - logging frameworks for
.NET
*
List of web analytics software
This is a list of web analytics software used to collect and display data about visiting website users.
Self-hosted software Free / Open source ( FLOSS)
This is a comparison table of web analytics software released under a free software license ...
*
Logbook
A logbook (or log book) is a record used to record states, events, or conditions applicable to complex machines or the personnel who operate them. Logbooks are commonly associated with the operation of aircraft, nuclear plants, particle accelera ...
*
Log4J
Apache Log4j is a Java-based logging utility originally written by Ceki Gülcü. It is part of the Apache Logging Services, a project of the Apache Software Foundation. Log4j is one of several Java logging frameworks.
Gülcü has since c ...
*
Log management and intelligence
Log management (LM) comprises an approach to dealing with large volumes of computer-generated log messages (also known as audit records, audit trails, event-logs, etc.).
Log management generally covers:
* Log collection
* Centralized log aggr ...
*
Logging as a Service (LaaS) Logging as a service (LaaS) is an IT architectural model for centrally ingesting and collecting any type of Logfile, log files coming from any given source or location; such as Computer server, servers, Software application, applications, devices et ...
* Pantheios – logging API library
*
Runtime intelligence
Software analytics is the analytics specific to the domain of software systems taking into account source code, static and dynamic characteristics (e.g., software metrics) as well as related processes of their development and evolution. It aims ...
*
Server log
In computing, logging is the act of keeping a log of events that occur in a computer system, such as problems, errors or just information on current operations. These events may occur in the operating system or in other software. A message or lo ...
*
Web counter
A web counter or hit counter is a publicly displayed running tally of the number of visits a webpage has received.
Web counters are usually displayed as an inline digital image or in plain text. Image rendering of digits may use a variety of ...
*
Web log analysis software Web log analysis software (also called a web log analyzer) is a kind of web analytics software that parses a server log file from a web server, and based on the values contained in the log file, derives indicators about when, how, and by whom a web ...
*
XML log
XML log or XML logging is used by many computer programs to log the programs operations. An XML logfile records a description of the operations done by a program during its session. The log normally includes: timestamp, the programs settings duri ...
References
{{Authority control
Data logging
A data logger (also datalogger or data recorder) is an electronic device that records data over time or about location either with a built-in instrument or sensor or via external instruments and sensors. Increasingly, but not entirely, they ar ...
Computer logging