For the homework#3 of this week, I had a chance to practice on the docker compose. However, excepting for the little knowledge that I learned from the activity 10 in class, I had no clue what docker compose was. Therefore, I wanted to learn more about docker compose to get a better understanding and also learn how to write a docker compose file.

Docker Compose Tutorial: advanced Docker made simple is one of the resources that I find useful to help me get an overview about the docker compose, how to write an .yml file, and how to run the .yml file with docker-compose commands. Through the website, I know that docker compose is used to define and run multi-container Docker applications; and I also get an idea of what components should be included in a .yml file to create a docker container. Specifically, to create a container service, we need some entries like build, link, image, ports, volumes, command, environment, etc.; and the function of each entry is also described in detail on the website. For example, back to the activity 10 in class, now I am able to convert the docker command given in the below picture to an equivalent .yml file.

As shown in the above docker command, my .yml file will create a container named cache using the image named redis with the tag of 6.0.8. This container has internal port 6379 connecting to the external port 11000, and it also mounts two directories of ./redis.conf and /etc/redis.conf. So, the components that should be included in my .yml file are version, services, web, image, ports, and volumes.

First, version is to define which version of docker compose that I am using. Services is used to define all different containers that I want to create. Web is use to present the container name, in this case, I will replace web with cache. Image will represent which image is used to create the container (redis:6.0.8). Ports is used to map the external port with the internal port (11000:6379). Volume is used to mount the source directory, ./redis.conf, with the destination directory, /etc/redis.conf.

In short, in my opinion, I believe the website that I found is a good resource, because from it, I can find really useful information about docker compose, such as definition of docker compose, how to write .yml file, and docker-compose commands. Thanks to this resource, I am more familiar with .yml file and docker-compose commands. Especially, I used what I learned from this website to do my homework 3.

From the blog CS@Worcester – T's CSblog by tyahhhh and used with permission of the author. All other rights reserved by the author.

• Creational
• Structural
• Behavioral

In what is called software engineering, a design model describes a solution that is determined by the problems found in the design of the software. It makes it possible to represent practices that are best and which evolve over a longer period of time through gaming but also testing that is done by software experienced developers.

1)Creational Design Patterns are patterns that explain how an object can be created. These models make it possible to reduce the complexity but also the instability that they have by making the creation of objects in a more controlled way.

In most cases, the new operator is often considered harmful as it distributes objects throughout the application. This can become even more challenging over time, in order to change the implementation, for the sole reason that the classes have a very close relationship with each other.

Creative design models address this issue here by making the client disconnect from the initialization process that is currently underway.

1. Singleton – Makes it possible to provide a single instance of an object that exists during an application.

2. Factory Method – It is possible to create different objects of different classes that are related, but without making specifications in the exact object that can be created.

3. Abstract Factory – Makes possible the creation of families that are dependent but also connected together.

4. Builder – Has the ability to build complex objects using one approach after another, or in other words step by step.

2) Structural design patterns– These are models that have to do with what is called the organization of objects and classes that are different, but also that change the formation of structures from the largest, but at the same time to make it possible to provide the functionality of ri.

Explain how the structural design model is used-

At the moment when we have two interfaces that have an incompatibility with each other but also that want to have a relationship between them by having adaptation with each other, it is also called as the adapter design model. This model, also known as the adapter model, converts an interface of a class to an interface or another class that the client expects. In other words, what is called adaptability somehow allows the classes to work together, which at another point due to incompatibility could not have happened otherwise.

3)Behavioral design patterns represent the responsibility but also the interaction of different objects.

By generalizing these design models, the interaction that takes place through objects should be in such a way that they too can talk smoothly to each other.

Translated into simpler words, in order to avoid dependencies but also difficult coding, the application and the client at the same time should be connected as loosely as possible.

Behavioral design models have 12 types usable for this model:

1. Enterprise chain model

2.Command model

3.Performer model

4.Iterator Models

5.Broker model

6.The model of memories

7.Observer model

8.The state model

9.Strategy Model

10.Template model

11.Visitor model

12.Object Null

References:

https://www.gofpatterns.com/design-patterns/module2/three-types-design-patterns.php

https://howtodoinjava.com/design-patterns/creational/

https://howtodoinjava.com/design-patterns/structural/

https://www.ifourtechnolab.com/blog/a-complete-guide-on-behavioral-design-pattern-and-chain-of-responsibility-pattern-in-java

From the blog CS@worcester – Xhulja's Blogs by xmurati and used with permission of the author. All other rights reserved by the author.

Unified Modeling Language otherwise known as UML is one of many different modeling languages/types used in programming. The purpose of modeling languages such as UML is to show the structure of code in order to better understand it. Widespread use of UML started in 1997 when it was adopted as a “standard”. UML is used with object oriented programming and is separated into two different categories (Structural and Behavioral Diagrams). Structural Diagrams show static aspects of code while Behavior diagrams show the dynamic parts of code. 

Some concepts listed that are a big part of UML are Class, objects, inheritance, abstraction, encapsulation, and polymorphism; all of these are directly related to object oriented programming. A few types of structural uml diagrams are class diagrams which show static structure, composite diagrams which show internal code structure and show how the code being analyzed acts when it comes to the rest of the program, an object diagram shows what instances are in code and their relations/associations, component diagrams show the organization of a systems physical components. Some Behavior diagrams from uml are state machine diagrams which represent the “state” of the system, Activity diagrams show a systems control, sequence diagrams show interactions between the objects. 

I chose this article as we have worked on UML diagrams in class and this article is structured well and tells the readers what exactly UML is without overloading them with information. Readers are presented with what UML is and different ways it is used to show many different things involved in object oriented programming. The site which the article is on also has multiple other articles which show readers more complex aspects of UML so if they want to dive deeper into the subject they are free and able to do so without having to look for another website for the desired information. 

I liked this article because of its simple format and feel that it helped me when working on assignments regarding uml even though we mainly went over class diagrams knowing the other types of diagrams and what they are used for was interesting and even helpful to me in understanding the significance of class diagrams. Each diagram in UML has a “specialty” you could say as each different diagram type maps out something different and even with class diagrams being rather simple they can help you understand the benefits that UML provides for software based fields.

https://www.geeksforgeeks.org/unified-modeling-language-uml-introduction/?ref=lbp

From the blog CS@Worcester – Dylan Brown Computer Science by dylanbrowncs and used with permission of the author. All other rights reserved by the author.

Docker is a relatively new way of software delivery. With Docker, all that is needed is the image for the dependencies and software needed, and Docker does the rest. This is huge as before you would need to download and install specific versions of software on each and every computer you wanted to work on, but with Docker, you say you want X, Y, and Z and Docker does the rest for you, making life much easier.

The way Docker does this is through what are called “Containers”. Containers allow developers to package an application with everything that it needs, like dependencies and libraries, and then ship it out as one package. This is where the magic happens, as it means that the application will run on any other machine regardless of any customized settings that machine may have that might differ from the main machine that is being used for writing and testing the application. Docker is, in a way, like a virtual machine in this sense, but instead of running an entire virtual operating system, Docker allows applications to run the same kernel as the system they are running on, and only needs applications to be shipped with things not already on the host computer, instead of having to send out everything. This translates to a big performance increase in the speed of the application and reduces the overall size of the application as well.

Docker is also open source, one of the most important things, in my opinion, software can be these days. This means that anyone can contribute to Docker and modify it to their own needs if they need something Docker does not provide by default. This also means that since anyone can modify it, they can also see the inner workings and ensure that nothing is going on that’s not supposed to, like recording private information to sell to advertisers, for example. Docker makes life easy for developers, allowing them to not have to worry about the system that their program will be running on. Docker also gives flexibility in it’s containers and can reduce the number of systems needed for the program to run.

Source

I choose the above article because it gave a good look into what Docker is and how it is useful for software development in today’s world. It explained the key aspects of Docker and what they are useful for compared to past methods. In addition, the article gave a good analogy to Docker by comparing transporting cargo prior to the standardization of using shipping containers to make transporting good easier, as that roughly translates to what Docker does with their containers.

From the blog CS@Worcester – Erockwood Blog by erockwood and used with permission of the author. All other rights reserved by the author.

Applications such as Expedia, Amazon, Netflix or Facebook are using an API that facilitates the sharing data from one application to another. There are hundreds of APIs for many fields like finance, social network, payments and e-commerce. Nowadays, the fastest-growing category APIs is sharing and analyzing of data across various applications which is a place the characteristics of the API determine the value of the application or deem it untenable for use in the real world. But how could APIs connect each application together, let’s us take a deep dive into the world of APIs.

API stand for Application Programming Interface which includes three important components

• Procedures: Known as routine which refer to the specific tasks or functions a program performs. For example: Facebook provides a search API for developers to examine data for analytical purpose
• Protocols: The format is used to communicate data between applications. However application might not have the same format
• Tools: Simply put – building blocks which is the recipe to construct new program

APIs are needed to bring applications together to perform a designed function which allows to use, share and execute data. APIs act as middle man, this allows developers to build new functions between applications and businesses use on a daily basis.

How APIs actually work?

Application: Enterprise businesses and corporation rely onto user financial data, inventory levels and purchase order confirmation back and forth between suppliers, customers and partners. Consumers and business depend on mobile application, spending much time per day on smartphone and tablet apps to exchange businesses with partner and customers.

Programming: Application relies on programming. The application does not make itself. In other words, we would not be able to make new application without developers who write the code to create, testing and design the application software and user interface.

Interface: This is where users and application interact with each other

API is important that without it we would not be able to order stuff from Amazon or personalize your favorite Google homepage. The simple way to understand APIs is to understand that API is an interface that let this application talk to another inside the application via commands designed by programmers.

Types of APIs

• Rest APIs: known as RESTful APIs, stands for Representational State Transfer. It has grown in popularity of late, as an essential part of Web Services. It’s designed for developers to perform requests and receive responses via HTTP. There are four types of HTTP commands that REST is based on which are GET, PUT, POST, and DELETE. Instagram uses API for users to pull up information and pictures
• SOAP APIs: Stands for Simple Object Access Protocol. SOAP is a protocol that is defined by a standard. It is dependent on XML-based systems and programming, has larger and more expensive data. Despite the disadvantages, SOAP provides better security for users.
• RPC APIs: Remote Procedure Call was the earliest form of APIs. They are designed to execute the block of code on different servers.

APIs are running data for business every day. They give businesses and users the flexibility to increase productivity and improve security. Taking advantage of APIs can help them have innovative approaches. While the potential is undeniable, efficiency is still another matter.

Source:

https://www.cleo.com/blog/knowledge-base-what-is-an-api

From the blog CS@Worcester – Nin by hpnguyen27 and used with permission of the author. All other rights reserved by the author.

Whenever you interact with a program it is usually done through an API. Every website you visit, most programs you use, even your own operating system uses APIs to communicate with application. APIs are very prominent in modern computing and are essential to establishing the connection between programs and users alike.

Seeing as every programmer will interact with an API at some point or another, it is important to understand their place and how to create a good API should you need to do so. It is important to realize that characteristics such as being easy to work with, complete, and concise must be met when creating an API. Doing so can result in many gains not just in the finished product, but in other aspects of coding projects. Keshav Vasudevan put it, good API design can lead to “improved developer experience, faster documentation, and higher adoption for your API.

As the author puts it, an API must be extremely simple to use while achieving its goals. To that end Vasudevan has outlined key aspects of API design that one should take into account when creating an API. Much of it comes down to proper organization and the use of consistency to avoid confusion while utilizing the API. Small changes such as keeping URLs short and simple along with setting up resource functionality with HTTP methods can make the process much easier. Methods such as GET, POST, PUT, PATCH, AND DELETE are commonly used in these APIs along with many other methods commonly used in HTTP.

Along with proper organization while building the API, it is just as important to ensure that it is not indecipherable by others. A problem that often occurs with developers and product owners is that the developers might the meaning of a feature and implement incorrect functionality. Developers should check that all GET commands needed are implemented and have an example where one can expect a specific output on a successful run. It is important to give and receive feedback for the developers due to the disconnect that can occur between the target audience of a program and the developers creating it.

An example of the GET response as follows:

responses:
200:
description: Successfully returned information about users
schema:
type: array
items:
type: object
properties:
username:
type: “string”
example: “kesh92”
created_time:
type: “dateTime”
example: “2010-01-12T05:23:19+0000”

Once all this is done, it is important to remember that complexity should be handled ‘elegantly’ as Vasudevan puts it. This entails that there are likely large amounts of different data and information that must be accessed. A lot of these are common and it makes no sense from an efficiency standpoint to create a resource for each piece of data, therefore it is important to keep the ability of resources broad. You should keep the retrieval process simple, down to a query and parameters when searching or using a resource. Overall the API must be as user friendly as possible to ensure that it works well with future users who don’t know the API like you.

Bibliography

Vasudevan, Keshav. “Best Practices in API Design.” SmartBear.com, https://swagger.io/blog/api-design/api-design-best-practices/.

https://swagger.io/blog/api-design/api-design-best-practices/

From the blog CS@Worcester – George Chyoghly CS-343 by gchyoghly and used with permission of the author. All other rights reserved by the author.