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WakaTime’s infra is split across DigitalOcean and AWS. We use DigitalOcean Droplets for compute resources, AWS S3 to store code stats, and DigitalOcean Spaces for backups. You can find more info on this split infra decision in this blog post. The files we store in S3 are usually between 10KB and 50KB in size, and we store multiple terabytes of these files. We don’t use Spaces CDN, and our Spaces ...

1. Introduction In the third part of this series of articles about real-time stream processing we learned how to import the .json flight data files to ElasticSearch using its bulk API as well as its low-level and high-level REST APIs. In this article we will introduce yet another way, Logstash. 2. What is Logstash Logstash is an open-source data collection ...

Redis is an in-memory database with very high write and read speed, and a limitation that data sets can’t be larger than available RAM. It’s like memcached but supports data structures instead of just strings as values. Redis is great for caching lookups to AWS S3 from an external server, which can speed up your S3 reads and save you money on Outgoing Data ...

Writing asynchronous code in Javascript is relatively easy. // async function let attempt = 1; while (true) { try { const result = await operationThatMayFail(); // it didn't fail return result; } catch (error) { if (attempt >= maxAttempts || error !== 'Retryable') { // either unhandleable, or no further attempts throw error; } } attempt++; await sleep(pauseTime); } This ...

When writing a test it’s important to test both positive and negative scenarios. It’s important to test edge cases. However, when choosing test data, the test data needs to illustrate the test case well. If the test data is hard to connect back to the exact use case, then it can lead someone to misunderstand the test, its implied specification, ...

As soon as we hear the word mobile, we realize that it has majorly occupied the human space. Internet, videos, music, social networks, navigation, etc. you name it and you’ve got it. The relationship between mobile apps and human beings has become an unshakable bond. As the mobile app trends progress, it becomes a dire need to have a robust ...

Concurrency control can be an important part of a REST API, especially if you expect concurrent update requests for the same resource. In this post we will look at different options to avoid lost updates over HTTP. Let’s start with an example request flow, to understand the problem: We start with Alice and Bob requesting the resource /articles/123 from the ...

In our previous post, we saw how to upload a file using the Spring framework’s default implementation for MultipartFile interface. In this post, we will see how we can use the Commons FileUpload library and the wrapper implementation CommonsMultipartFile provided by the Spring framework. Update the pom.xml We will update the maven dependencies to include commons-io and commons-fileupload. We will ...

Uploading files is one of the most common operations in a web application. In this article we will look at how to upload file from an HTML page and copy it to the file system on the server. Creating a HTML form with file upload option The below HTML code and its corresponding Javascript code creates the HTML form and ...