The data collected inform key business decisions. For example, you can determine peak hours when customers place orders using your web application. With such insights in hand, the management can make informed business decisions to scale up revenue. Unlike Elastic Search , Graylog offers a single-application solution in data collection, parsing, and visualization. It rids the need for installation of multiple components unlike in ELK stack where you have to install individual components separately.
Graylog collects and stores data in MongoDB which is then visualized on user-friendly and intuitive dashboards. Graylog is widely used by developers in different phases of app deployment in tracking the state of web applications and obtaining information such as request times, errors, etc. This helps them to modify the code and boost performance. Written in C, Fluentd is a cross-platform and opensource log monitoring tool that unifies log and data collection from multiple data sources.
Fluentd processes both structured and semi-structured sets of data. It analyzes application logs, events logs, clickstreams and aims to be a unifying layer between log inputs and outputs of varying types.
It structures data in a JSON format allowing it to seamlessly unify all facets of data logging including the collection, filtering, parsing, and outputting logs across multiple nodes. Additionally, it boasts of a flexible plugin architecture where users can take advantage of over community-developed plugins to extend its functionality.
LOGalyze is a powerful network monitoring and log management tool that collects and parses logs from network devices, Linux, and Windows hosts. It was initially commercial but is now completely free to download and install without any limitations.
It also provides extensive search capabilities and real-time event detection of services across multiple nodes. Like the aforementioned log monitoring tools, LOGalyze also provides a neat and simple web interface that allows users to log in and monitor various data sources and analyze log files.
NXlog is yet another powerful and versatile tool for log collection and centralization. NXlog has the capability of collating events logs from numerous endpoints in varying formats including Syslog and windows event logs. It can perform a range of log related tasks such as log rotation, log rewrites. You can download NXlog in two editions: The community edition, which is free to download, and use, and the enterprise edition which is subscription-based.
TecMint is the fastest growing and most trusted community site for any kind of Linux Articles, Guides and Books on the web. Millions of people visit TecMint! For lawyers, like myself, it can be difficult to discern technical references in a license written by a developer. And I am sure it is equally frustrating for developers encountering legalese in a more traditional open source license.
With that said, grasping a basic understanding of open source software licenses does not have to be a challenge. As an attorney at Capital One supporting our Open Source Program Office I help educate our software engineers and developers on the impacts of using code under the various open source licenses. That education leads to a better understanding of company policy and helps developers think strategically about what open source software they use in their projects.
The easiest way to understand open source licenses is to take a step back and look at patterns in the licenses. When you do that you see it is possible to group licenses that share common terms into certain categories:. This post will compare the different license categories, explaining what they mean, what you need to know about using a license in that category, and why you might choose to use code under a license in the category. I will also address the concept of Public Domain as a separate category from open source licenses.
The category of permissive licenses is a great starting point because generally these licenses are the easiest to understand. There are hundreds of variations of permissive licenses, but they all boil down to the same thing.
With a permissive open source license you can do whatever you want with the code, just give the original author recognition as required by the license. The main thing you may want to do, that is not always possible with other categories of open source licenses, is license the code under a different license.
The language of a permissive license lets you combine the original code with your own code and then license that combined work with whatever license you want, or even no license at all.
That is what distinguishes permissive licenses from the different versions of copyleft licenses that will be discussed later. If it sounds simple, it is. Permissive licenses are designed to be appealing to a wide audience of users.
Almost always, you are asked to recognize the original author by including a copy of the license with your program. This retains the copyright notice and tells subsequent users that the program contains open source software under a permissive license. The idea being that a person could track down the open source code to review it themselves. Henry, a developer, wants to use Library A in his project.
Library A is under the MIT license , a permissive open source software license. Henry wants to make modifications to Library A and combine it with his own proprietary code. If we think of the open source license categories as a spectrum, next to permissive licenses are the slightly more restrictive weak copyleft licenses.
Before getting into what makes a license weak versus strong copyleft it is important to understand the concept of copyleft itself. Copyright has traditionally been used to exclude others from your original work and copyleft is essentially the inverse of that concept. Copyleft uses copyright to dictate downstream usage rights.
With a copyleft license you grant others rights associated with the work and require that they too will grant those same rights if they turn around and convey the work to someone else. You are not excluding others from the work so much as inviting others to use, modify, and redistribute the work with the requirement that those permissions remain intact. The mechanism to keep those permissions intact is the requirement that the license stays the same. Whether the license must apply to just that particular open source component and any modifications to it , or to any code linked to the open source component, is the difference between weak copyleft and strong copyleft.
Weak copyleft open source software licenses are those that require the original code, and modifications to that code, to remain under the same license. You may combine code under a weak copyleft license with other code under different licenses because the weak copyleft license only applies to the individual component and not the broader program.
Often the component must be distinguished from the rest of the application, usually by requiring it to remain in a separate file. The draw of a weak copyleft license is that you get some benefit of the copyleft concept the ability to see improvements and modifications to your original work , while still appealing to users that may shy away from strong copyleft licenses because of concerns about the need to disclose the source code of their broader program.
One important thing to understand with weak and strong copyleft licenses is that the trigger for the conditions in the licenses is distribution. Distribution is a concept from copyright law, which is basically the act of giving someone a copy of something.
In other contexts, this is very straightforward. With a book, for example, if I make copies of the book available and hand you the book it has been distributed. You received a copy of it. With software it is slightly more complicated. If a user downloads the software to their device or is provided a copy of it on a flash drive it has been distributed. But increasingly software is developed using a SaaS model and in those instances users are accessing the software, but not receiving a copy of it, so distribution has not occurred.
More on that subject in the discussion of Network Copyleft licenses, but for now what is important to understand is that if there is no distribution the copyleft requirement for a weak copyleft license does not apply. Henry has modified Library B to fix a bug. The program will also contain additional proprietary code.
This particular license somewhat straddles the line between weak and strong copyleft and does not really fit in perfectly with either category. The important consideration for a library that is licensed under the LGPL is how it is linked within the application. If it is dynamically linked it can generally be treated as a weak copyleft license. If it is statically linked there are other requirements for compliance. With an understanding of weak copyleft it is easier to grasp what constitutes a strong copyleft open source software license.
A strong copyleft open source software license applies the copyleft requirement more broadly to the larger program instead of it being limited to the single component. In other words, if you use code under a strong copyleft license within your program you generally though not always would need to apply the terms of the strong copyleft license to the entire program.
This is an important question because it defines the scope of the copyleft requirement. This is a completely valid concern — organizations like Google, for instance, will ban use of AGPL3-licensed software entirely. If no one uses your software, then you've failed before you've started. Although widespread adoption is undoubtedly the top goal of any new open source company, it's not really clear what your license should optimize for. If the goal is to maximize value, should your license prefer low adoption resistance or high value capture?
To answer this question, let's turn to OSS. As of Nov. While most commercial OSS companies are permissively licensed, GPL and copyleft licenses seem to occupy the majority in value. This isn't surprising. Intuitively, restrictive licenses should allow you to capture more direct value from your creations.
If we consider a breakdown of average valuation by license type, the prominence of permissive licenses seem to diminish considerably:.
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