Easy cloud option for a problem statement in GO Lang

Most part of my career I worked on Windows based systems, when cloud computing evolved, in one of my previous companies I had a great opportunity to work on open sources stuff Go Lang and Mongo Db. My manager was not intended to experiment on business critical application using GO Lang. But understanding the ease of compilation and scalability of Go he was convinced, so I did a POC. It got approved and moved to production after a through testing .The entire  application development was done on Windows 7 running machines.

Since the organization has sufficient resources (man, money and metals) my job was only to develop the application using GO Lang and provide binaries for Linux and Windows servers. 

Problem statement:

After couple of years, one of my close friends (Naveen) come up with an idea to develop remote monitoring system using telemetric devices, since he is an instrumentation engineer, did research and selected two telemetric devices.

The idea is, we install telemetric devices in heavy machinery, and periodically telemetric devices send extensive information(what he calls it as extreme instrumentation engineering)  to the server. The added value is  to monitor systems and give sensible notifications to the end user about the health and status of the machines. 

Since each type of the device contains different protocol to send and receive data, we decided not to go ahead with any vendor specific server. Vendor servers are designed to work only with their devises and they impose many rules to use them. So we planned to design a server that should suffice all kinds of protocols. 

What we need to up the application , our initial solution?

As it is an experimental stuff , we do not want to spend so much of money but the below are the basic requirements to embark the project execution.

• Required equipment

1.  Teltonika FM5300  (Purchased) 
2.  Ruptel device (Purchased) 
3.  Two Simcards with data bundle (Thought to use our spare sim cards) 
4.  Static IP address (Took MyStaticIP Subscription 23$ @ month)

•  Required software

1.  Two windows development machines ( Personal Laptops) 
2.  Visual studio as we started writing using C# (Express version)
3.  SQL Server database (Express version) 
4. Source control ( Not to use at the moment)
5. Windows based server( Looking for free hosting options)

Somehow spending very limited amount we could arrange all required stuff and start developing server using Microsoft stack.

Server development was impressive, tested with device satisfied with the development. We then started analyzing similar products and market requirements, what we understood is most of the companies are struggling to scale their servers due to technology constraints when there is high demand from their clients.

For example 1000 devices are connected and every 10 sec a device has to send data to the server... 1000 * 3600/10 * 24 = 860000 transactions per day.  Actually 1000 devices are very minimal for an average sized company in the market.

Re-designing the problem statement from the nonfunctional requirements point of view

• We had a lengthy discussion and decided to considering the below requirements as well
•   As more number of devices with more frequency of request-response cycle are configured
•  Server resources should be scalable
•  Server application can be configured to multiple platforms as the application may be moved to different clouds based on the future financial and technology decisions
• As type of the devices grow, code changes and then binaries change, so agile, easy compilation and easy deployment options to be considered
•  Easy to host options to be considered
• Open source and free technologies and tools to be used
• Development should be inclined with evolving cloud frameworks

As our non-functional and deployment requirements changes it directly impact development technology stack, hence it require redesign as below.

•   Required equipment

1.  Teltonika FM5300  (Purchased)
2.  Ruptel device (Purchased)
3.   Two Simcards with data bundle (Thought to use our spare sim cards) 
4.   Static IP address (Took MyStaticIP Subscription 23$ @ month

• Required software

1. Installed Ubuntu instead of Windows.
2. Go Lang with LiteIDE
3.  MongoDB with MonghChef
4. GIT and made our application as opensource on GITHUB
5. Linux Server

We started re-developing the application, using GO Lang and MongoDb as NOSQL database.

As I am not a usual Linux user , it took me 2 days., to install Ubuntu, understand Linux commands and directory system.

Configured GO , MongoDb, LiteIDE ,MongoChef ,GIT  as very nice installation guides are given.

Configured Go and Mongo environment variables and GIT directorys are configured according to my desired directory structure , every thing is up and and development application is running well.

After spending 15 days of time , could develop a very good concurrent server using Go Lang, it is really fast and tested with 10,000 virtual clients with the frequence of 5 sec a request (Cannot purchase many devices and configure)

We made one of our laptop as server and compiled the binaries and configured the server with Static IP every things works fine

To test server scalability, we created upto 4 Linux containers  configured server application , application is smoot and dam .. good.

Developing & hosting on cloud

After a little search  on Amazon, Microsoft, Google cloud services decided to go with Www.Koding.Com which is a simple and efficinet , free cloud provider for research and expermental projects.

What benefits we get with Koding.Com?

•  A clean Ubuntu terminal with reasonably good resources
•  Any package can be installed on the provided VM as sudo permissions are given to you.
•  GoLang , GIT are pre-installed so, cloning from GITHUB is very easy. Using Go tools source can be compiled and binaries are extracted with hassle free.
• Could install MongoDB and required tools as easy as I could do on my personal machine
• The biggest benefit we got is, we get a public ip for free so all clients can communicate the the server hosted on Clould free of cost. Only the issue is IP changes for every server reboot. This alone saves us 25$ a month and no need of any additional server required.
• As we move to production, without changing the set-up can upgrade to a commercial package.

What you should know to use Koding.Com Cloud?

•   Should know to use Linux terminal and Linux basic commands (ls,mkdir,mv,rm etc..)
•  Should know to configure .bashsr and .profile environment settings on Linux
•   Should know to install required packages using apt-get

This is all how we develop an application and trying to move it to production with limited resources in hand.

Any enthusiastic developers can develop and host applications on cloud without spending a single penny.

I am very much thankful to the open source community and Koding.Com. 

Pointers in Go Lang

Pointers is a kind of concept to be learned with eminence and passion. I don’t think, a short and terse explanation on Pointers is really worth full. Unlike C Lang Pointers(open to perform and better performer one way), Go’s pointers are designed with extreme care so that certain Pointer manipulations are separated from core design and kept in a package called “unsafe”. In this post, concept has been segregated into different sections starting from creating pointer to different scenarios in Go Lang.

Here are the sections the whole concept is segregated into

What is a Pointer?

What are the differences between Go Lang and C pointers?

Why Java does not have pointers?

What are main advantages of pointers in Go Lang?

Maintaining object life cycle using pointers

Unsafe package in Go Lang

Pointers in function parameters

Pointers in Structs and Struct receivers, Struct methods

Pointers in Interfaces

Here is the explanation

What is a Pointer?

Like in C language, Pointer is a variable which is used to store address of another variable. Every variable is stored in a memory location and every memory location has an address hence, Pointer in Go Lang is used to hold an address of another variable. Have a look at the below figure.

50 is the value of a variable and 1001 is the address of 50. So pointer holds 1001 which is the address of 50 and even pointer also has its own address which is 2047. So far, Go’s pointers story is same like C Language.

Go uses &(ampersand) and *(asterisk) operators for pointer manipulations. In addition to them there are other types and packages available for pointer manipulations. We will discuss about them in later sections described below.

Just keep in your mind that a pointer variable always keeps the address of a variable.

The below figure explains a simple and very first pointer example.




Creating Pointers example

Download above example from :Pointers example-1

De-Reference a Pointer: Any pointer variable can be de-referenced by using “nil”. E.g.

var value int8 = 100 var Ptr *int8 = &value Ptr=nil

Now Pointer variable “Ptr” is not referenced to any variable.

void Pointer : Like in C language there is no discrete keyword like void in Go Lang. Void pointer similar functionality can be obtain using unsafe package.

Pointer arithmetic: This feature is not included as a core feature in Go Lang. According to Google’s view pointer arithmetic to be done with great care and necessity.  

(Other sections yet to be completed so stay tuned)

 

Types in Go Lang

Understanding the way “Types in Go Lang” work is a very essential step in order to write better and precise programming.

Go is a statistically typed language. That means, each variable has a type and once type is given to a variable that type cannot be changed. But of course there are situations where we need to switch between types using dynamic typing.

· There are two Types in Go Lang

1.Named types : A type that is declared with pre declared type.Pre declared types: Boolean, Numeric and String types

2.Unnamed types: A type that is declared using previously declared types or a composition. Composite types:array, struct, pointer, function, interface, slice, map, and channel types. Composite types are constructed using literals

·Static or Dynamic type

1.Static type: A type of a variable when it is declared. Generally all types are static types. So once a variable is declared with a type it does not change

2. Dynamic type: Dynamic type is only applicable for interface variables. A type varies during the execution of the program. Ultimately any dynamic type should be assigned to a static type. I have explained more about dynamic type in type assertion section below.

 Rules to follow in types

· Implicit conversion is not possible from one type to another type in Go Lang, even though the value belongs to a pre defined type. So unlike in other programming languages int16 cannot be implicitly converted to int32.

var age uint8 = 47 var newage int16 = int16(age)// This is called explicit //conversion. Since age is uint8 explicitly converted

·  Unlike Java and C#, Go does not differentiate stack and heap memory.

· Methods can be assigned only to the types declared in the same package. Take a look at the example below. 

func (s string) Length(str string) int {     return len(str) } func main() {     var name string = "About types  in Go Lang"     fmt.Printf(name.Length(name)) }

The above program compiles an error, because string type is not declared in the same package. String is a pre declared type; hence, the rule is receiver of the method should be defined in the same package.

·  The below figure explains, how to create type from the underlining primitive types and how to create type from an existing type. It also explains type casting between types



                          Creating types from underlying types

Download above program from Creating and casting types

Type assertions

As all of us know and have experienced the importance of dynamic types in Java and C# programming. Dynamic types are very useful when using generic frameworks and design patterns. Dynamic type in Go Lang can be created by using empty interface {}.See the below code snippet

//The below types are declared dynamically using empty interface

 var name interface{} ="Jiten"

 var age interface{} = 33

  var address interface{} ="Bur Dubai, Dubai"

Once a value is assigned to a dynamic type, at any point of time it has to be assigned to its original type. Similar concept is boxing and unboxing in .NET family languages. Go’s way of dynamic type to static type is called type assertion. The below figure explains how to cast from dynamic type to variable’s actual type.

Type assertion & casting

  Download above program from Type assertion and casting

 

So far in this post, I gave overall information about types. Going forward I will post more specific about Pointer, Array, Slice, Map, Func, Struct , Interface and Channel types. Each post would give precise information about each of the types.

Enjoy Go Lang, stay tuned, thanks for reading.

Overview of Go Lang

Go Lang project initiation

·       Go Lang is an open source project started at Google in 2007. Main designers of this language are Robert Griesemer, Rob Pike(Unix designer), and Ken Thompson(Unix designer). In 2009 it was declared as an open source project and then about 450 developers from various parts of the world involved in writing various packages for Go Language.

·       Go Lang core libraries are designed using C Language and later using Go lang itself.

·       Go Lang features were influenced by C, Python, Pascal and Java languages.

Why Go Lang?

·       Go is a general purpose programming language like C language. Preferably a systems programming language.

·       C language was developed about half a century ago, and programming community still consider it is worth to learn because of its robustness, simplicity and performance. But certainly it lacks in some areas like utilizing multi core processors, cloud computing and Web, since at the time of C Lang development, these features did not exist.

·       The aim of Go language is not to replace C language. In fact it uses C language for Go’s core packages. So the aim is to  produce a concrete general purpose language similar to C in terms of simplicity , performance and robustness by utilizing latest updates in hardware and software technology to ease programming.

·       All programming languages right now are targeted to develop enterprise application (like Java,C#) , web applications(PHP ,RUBY etc..) or for any specific purpose . But there is no single modern language which can fulfill the gap that a general purpose language can suffice by giving advantages of Java like garbage collection, Python and VB like simplicity and C++ like performance. Here Go exactly fits.

Go- important features

·       Works on all major operating systems (Windows, Mac, Linux, Plan9 etc...).

·       Wonderful tool set for cross compilation on various processors and OS architectures like ARM 5, ARM 6, Win 32, Win 64, Linux 32,64 etc…

·       Comparatively fast compilation, hence application opens faster than many other programming language applications.

·       Hundreds of packages already are developed , tested and used by open source community.

·       Community developed many IDEs to develop Go applications. Some of them are Eclipse Add in, IntelliJ for Go, LiteIDE (Specially designed for Go).

·       Like many other programming languages Go Lang does not entertain warnings during compilation. Compiler gives only errors , no warnings. For e.g. if you declare a variable or a package and it is not used then according to Go Lang compiler it is an error.

Go Lang- important features

·       First class focus on concurrency patterns using Go routines and channels. Hence, better performance can be obtained from multi core systems. This is one of the key reasons of its wide adaptability.

·       Go is a very light weight language. There are fewer checks by compiler in comparison to  Java, C# and C++ etc... so compilation with Go is faster than many other language compilations.

·       Go is a Garbage collected language. Statically typed and type safe language.

·       There is no need to give “;” at the end of each statement. Compiler can automatically understand from the source code. Similarly programming has been simplified whereever it is possible in Go Lang.

·       Easy and effective variable type declarations.

·       Multiple return values from functions and methods.

·       Has different way of exception handling. There are no try catch blocks in Go.

·       Arrays, Slices and Maps are innovative and robust.

·       Innovative and different approach for Object Orientation. No classes in Go Lang but we can obtain similar features from structs and interfaces

·       Different and innovative approach in using Interfaces.

·       Many packages are available for Web, Servers, JSON Web Services and database programming. Please check the following link for all approved packages https://golang.org/pkg/

 

Information on downloads

·       Download latest Go version from http://golang.org/dl/

·       Download LiteIDE from http://sourceforge.net/projects/liteide/files/
 

Since Go is a new language with different approach, there is always a chance to think and program in an innovative out of the box way . Enjoy learning Go Lang.

Stay tuned for more tutorials on Go language features.

 

 

 

 

 

 

 

 

Variable declaration and assigning values in Go Lang

   There are various ways to declare and assign values to variables in GoLang.

• Declaring variables using var keyword
• Declaring  variables and assigning values with a special assignment operator :=

Below images depict various ways of declaring and assigning values to variables



Variable declaration using var keyword and assigning values



Download above code from Variable declaration example-1

As mentioned earlier there is another way of declaring variables at the time of assigning values to them. It can be called as ad-hoc declaration . The below image explains how to do that

Variable declaration and assign value in an ad-hoc way

 Download above code from Variable declaration example-2

Thanks for reading, please do write your comments and correct me if some thing is wrong or some thing to be added to it. I will write advanced techniques in Go Lang in my upcoming posts..