When comparing Go vs Grails, the Slant community recommends Go for most people. In the question“What are the best web frameworks to create a web REST API?” Go is ranked 10th while Grails is ranked 21st. The most important reason people chose Go is:
Goroutines are "lightweight threads" that runs on OS threads. They provide a simple way for concurrent operations — prepending a function with `go` will execute it concurrently. It utilizes channels for communication between goroutines which aids to prevent races and makes synchronizing execution effortless across goroutines. The maximum number of OS threads goroutines can run on may be defined at compile time with the `GOMAXPROCS` variable.
Specs
Question Ranking
Pros
Pro Exceptionally simple and scalable multithreaded and concurrent programming
Goroutines are "lightweight threads" that runs on OS threads. They provide a simple way for concurrent operations — prepending a function with go will execute it concurrently. It utilizes channels for communication between goroutines which aids to prevent races and makes synchronizing execution effortless across goroutines. The maximum number of OS threads goroutines can run on may be defined at compile time with the GOMAXPROCS variable.
Pro Simplified C-like syntax that is as easy to read and write as Python
The language is designed in a manner that seems logical. Syntax is simplified to reduce burden on the programmer and compiler developers.
Pro Great team working behind it
Go has a solid team of engineers working on it (some of the best networking engineers in the world are working on Go). Up until now, the great engineering of the language has compensated for its lack of power.
Pro The go compiler compiles binaries instantly — as fast as a scripting language interpreter
Compiled binaries are fast — about as fast in C in most cases. Compiles on every OS without effort — truly cross-platform compiler. As a result of the fast compilation speed, you can use the gorun program to use go source code as if it was a scripting language.
Pro API documentation is rich in content; easy to memorize
Only features deemed critical are added to the language to prevent cruft from working it's way into the language. The language is small enough to fit inside one's head without having to repeatedly open documentation. Documentation is hosted on an official webpage in a manner that is simple to read and understand.
Pro Programmers don't have to argue over what 10% subet of the language to implement in their software project
The language promotes programming in a specific idiomatic style, which helps keep every programmer on the same page.
Pro Built-in unit testing
The idiomatic approach to writing a Go software project is to perform test-driven development with unit testing. Every source code file should have an associated *_test.go file which tests functions in the code.
Pro Provides tools for automatically formatting code for your entire software project
This helps keep every programmer on the same page in a project and eliminates arguments over formatting styles.
Pro Easy to install and configure; simple to compile software
Go software can be immediately installed, regardless of your operating system, package manager, or processor architecture with the go get command. Software is compiled statically by default so there is no need to worry about software dependencies on the client system. Makefiles and headers are no longer necessary, as the package system automatically resolves dependencies, downloads source code and compiles via a single command: go build.
Pro Great language for building networking services
Go was started as a systems language but now it has fully committed in the niche of networking services. This has been a brilliant move by Go because it allows them to capitalize on the immense talent of the Go engineering team (who are in the most part network engineers).
In a world dominated by Java EE and slow scripting language, Go was a breath of fresh air and it continues to be one of the most powerful languages if you want to build networking services.
Pro Supports 'modules' in the form of packages
Every Go source file contains a package line that indicates which package a file belongs to. If the name of the package is 'main', it indicates that this is a program that will be compiled into a binary. Otherwise, it will recognize that it is a package.
Pro Demonstrates a unique, simple concept to object-oriented programming
All types are essentially objects, be they type aliases or structs. The compiler automatically associates types to their methods at compile time. Those methods are automatically associated to all interfaces that match. This allows you to gain the benefits of multiple inheritance without glue code. As a result of the design, classes are rendered obsolete and the resulting style is easy to comprehend.
Pro Automatically generates API documentation for installed packages
Godoc is provided to automatically generate API documentation for Go projects. Godoc also hosts it’s own self-contained web server that will list documentation for all installed packages in your Go path.
Pro Supports splitting source code into multiple files
As long as every source code file in a directory has the same package name, the compiler will automatically concatenate all of the files together during the compilation process.
Pro Multiple variables may be assigned on a single line
This conveniently eliminates the need to create temporary variables.
Fibonacci example: x, y = y, x+y
Pro Syntax for exported code from a package is simplified to be less verbose than other languages
Any variable, type and function whose name begins with a capital letter will be exported by a project, while all other code remains private. There is no longer a need to signify that a piece of code is 'private' or 'public' manually.
Pro Supports functional programming techniques such as function literals
This naturally also supports first class and high order functions, so you may pass functions as variables to other functions.
Pro Performance is on the order of C and Java
Go is blazing fast, but easier to write than Python, JS, Ruby, or many other dynamic languages.
Pro More than 900 plugins
Grails is a full-stack web framework, not just MVC. It contains a lot of stuff out of the box, but it doesn’t enforce it. It contains over 900 plugins which provide a Groovy API for a lot of useful and well-known Java libraries. And what is more important is that they are super easy to install!
Pro Very fast setup and scaffolding
Setting up a new project is quite fast and code generation (scaffolding) saves you a lot of time. It also uses a convention over configuration principle which helps you bypass all the configuration trouble.
Grails also comes with a reloading mechanism out of the box.
Pro Easy to use
Grails is designed to be a rapid development framework with a straight learning curve. It advocates convention over configuration. Extensibility is very simple when using plugins (there is a lot of them). One command in the console – and all the dependencies and configurations are managed for you.
Pro Grails is highly scalable
Grails is an abstraction over Spring and Hibernate. This makes Grails applications fast and scalable. This is because both Spring and Hibernate are themselves scalable.
Pro Great UI design alternatives
Do you need something advanced in the UI? You can either create it in GSP with an addon of CSS/JavaScript or you can find a plugin that will do the work for you. Plugins include integration with Bootstrap, jQuery, Yeoman and much more.
Pro Great documentation and community
The Documentation section is actually a wiki, which can be modified by any logged in user. It has an official manual, tutorials, screencasts, a sample app and much more. If that does not do it for you, then there are countless third-party tutorials, more than 12k questions on SO and much much more
Cons
Con Hard to abstract even the simplest notions
Go is famously regarded as very simple. However, this simplicity becomes problematic in time. Programmers who use Go find themselves over and over again writing the same thing from a very low point of view. Domains not already served by libraries that are easy to glue are very difficult to get into.
Con Designed to make the programmer expendable
Go was designed for large team projects where many contributors may be incompetent. That Go can still get things done under these conditions is a testament to its utility in this niche. Go's infamously weak abstraction power is thus a feature, not a bug, meant to prevent your teammates from doing too much damage. This also means any team member can be easily replaced by another code monkey at minimum cost. Good for the company, bad for you. The more talented programmers, on the other hand, will be very frustrated by having one hand tied behind their back.
Con Performance slowdown because of indirect calls and garbage collection
Practically no meaningful Go application can be written without indirect function calls and garbage collection, these are central to Go's core infrastructure. But these are major impediments to achieving good performance.
Con Easy to shadow variable
Due to single character only difference, declare and assign statement can easily shadow variable from outer scope unconsciously. Example:
err := nil
if xxx {
err := somefunctionthatreturnsanerr
}
return err // always return nil
Con No forms designer
I'm probably an old fart, but being a long time Visual Studio developer, I'm used to the luxury of having a forms designer for rapid development.
Con Implementation of interfaces are difficult to figure out
Finding out what interfaces are implemented by a struct requires a magic crystal ball. They are easy to write, but difficult to read and trawl through.
Con Weak type system
Con Grails is a fairly complex framework
Grails is a pretty heavy piece of software. It's functionality is covered by GORM (Grails' Object Relational Mapping) which is a facade for hybernate and by Spring MVC.
Everything is glued by core Spring and furthermore, Grails adds another level of abstraction on top of all this. These things may create some trouble down the road when debugging.
Con Too obtuse and JVM centric
If you're a big fan of the JVM and have mastered all its goofy quirks, Grails might be a good choice, but there are other frameworks out there that are more straightforward and easier to use.