Avatar (Fabio Alessandro Locati|Fale)'s blog

Inject DB connections in Golang gRPC API

March 21, 2022

One of the first issues that I had to solve when I started to use gRPC was how to inject a DB connection pool to the function handling the request. The DB connection injection is needed because creating a new SQL connection every time there is a new gRPC request (and tearing it down at the end) is a massive waste of resources. Also, this approach could limit the scalability of the API since the database probably has a limited number of connections it will accept.

Read More

CORS headers with gRPC-Gateway

July 28, 2021

A few years ago, I wrote a blog post on managing CORS headers with Negroni. Lately, I’ve created a new API server that needed to be accessible from the browser, but this time I used a different technology, more precisely gRPC-Gateway. Few months after I wrote that blog post, I stopped writing new REST services by hand. I did not rewrite all the services that used the old paradigm just because they needed a fix or a new feature, but for all new services, I moved to gRPC with gRPC-Gateway.

Read More

VPN with NAT in Google Cloud

March 1, 2020

Google Cloud provides the capability of terminating a VPN connection with a VPN Gateway. The problem is that the VPN Gateway - at the moment - is relatively limited in capabilities. One of the missing capabilities I would have liked to see implemented is the NAT capability. VPNs can be used to connect the machines of two different parties. Although this is usually not the best architectural pattern, since a connection on the public internet encrypted at the Transport Layer is often a better option, it’s relatively common in more legacy environments.

Read More

GoLang vanity urls on AWS Lambda

March 21, 2019

After the article on the reasons to use vanity URLs in Go and the one about how to implement a lightweight vanity URLs provider, I’d like to share with you how you can leverage AWS Lambda to implement a vanity URLs provider. The first thing we will need is to import the github.com/aws/aws-lambda-go package. This package will provide us with the needed functions to easily integrate our Go code with AWS Lambda.

Read More

Reasons to prefer vanity URLs for GoLang packages

January 18, 2019

Golang forces its users to use the repository URL of the dependency in the import statement. For instance, if we want to import the “test” package that is hosted at github.com/fale/test, we will need to use github.com/fale/test. On the one hand, this is very nice since it allows anyone reading the code to immediately understand where the code is hosted and therefore find it very quickly. Also, this URL-based import path guarantees that no two different packages can have the same import path, preventing this kind of confusion for both programmers and the compiler itself.

Read More

Calling a SOAP service in Go

December 3, 2018

Today the IT world is very focused on high performance, high throughput interfaces. In this situation, it is common to find REST and gRPC API, given their performances compared to the other solutions. Sometimes, though, we still encounter old API written with older techniques or new API that for some reasons have been developed with outdated technologies. One of those cases that I’ve encountered a few times over the last few months is SOAP.

Read More

CORS with Go and Negroni

November 18, 2018

There are some pieces that you need to put in every microservice you write. Those are for instance logging, error handling, authentication. Over the last year, I found myself writing over and over CORS headers. This requirement brought me to think that I should have used a Negroni middleware since we are already using Negroni for other middlewares. I started looking online for an already written one, and I found a bunch, but I was not happy with what I found, so I decided to write my own.

Read More

A lightweight approach to Go vanity import paths

September 23, 2018

Golang uses URLs for the dependencies packages resolution. To unbundle the code repository hosting the package and the import path, Golang supports the idea of Vanity Import Paths. The way this has been implemented is that, as long as the import path points to a page where Go can find the real package URL, it will follow through. So, we will need to create a web server that can serve pages in a way that the Go toolchains can understand.

Read More

A small HTTP debug server in Go

August 31, 2018

Lately, I found myself to work on an application that was communicating via SOAP with a server. My goal was to understand how this application worked with the SOAP server to emulate its behavior. Even if I had access to the source code of the application, I thought it would have been easier, faster and more fun to do the work without actually reading the code. It’s important to note that actually, the application is fairly small and self-contained.

Read More

libVirt on Hetzner

April 26, 2017

After many years of using Hetzner as a server provider, and having rented from them multiple servers for many reasons, I decided to rent a server with 128Gb of RAM to do some tests with many (virtualized) machines on top of CentOS. As it often happens, hosting providers put in place a lot of security measurements that sometimes make doing simple stuff more complex. The first approach I tried was using the (only) Ethernet interface as a bridged interface, but that did not brought me very far.

Read More
Older