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Bits and pieces

Between bits and bytes and all other pieces.
A tech blog about Clojure, Software Architecture, and Distributed Systems


Here some of my Open Source projects which you might be interested into.


active evolving production check-it-out stars

μ/log is a Clojure library for structured event logging. Contrarily, most of the existing log library which focus on logging human readable messages, μ/log offers APIs to log events and data-points. Human readable messages often encode data which it is then sent to centralized logging systems and loads of effort is put to extract useful information out of the string message. μ/log allow to send data directly and in a safe manner, enabling post processing and query aggregation in ways that other systems can’t.

On top of μ/log, I’m also building μ/trace, a micro-tracing library which allows to extends the basic event-logging capabilities with distributed tracing information.


active stable production use-it stars

safely is a Clojure Circuit-Breaker and retry library with a declarative approach. The purpose of the library is to simply and effectively handle retries declaratively making sure that in a large distributed system these retries won’t cause self-similar mass behavior causing more harm than benefit. The circuit breaker is implemented fully in Clojure and offers good features for observability..


active stable production use-it stars

1Config is A tool and a library to manage application secrets and configuration safely and effectively.

Here some of the key-points and advantages:

  • Easy way to retrieve and manage configuration for your AWS deployed services
  • Compatible with AWS Lambdas as well
  • AWS KMS envelope encryption for extra security (same as S3-SSE, EBS and RDS)
  • Support for key-rotation
  • Highly available (as available as DynamoDB + KMS)
  • Support for multiple environments in the same AWS account
  • Support for multiple services in the same environment
  • Support for multiple concurrent versions of the same service
  • Zero config approach (or at most 1 config ;-))
  • Anti-tampering checks for configuration entries (entries can’t be manipulated manually)
  • Supports Clojure, Java, Groovy, and other JVM languages (more to come)
  • Command line tool for managing changes to the configuration
  • Graphical User interface for managing changes to the configuration
  • Support for local development (outside AWS)
  • Highly-configurable and secure authorization.
  • Support for EDN, JSON, YAML, Java Properties and plain-text.

It has a very strong security model and very a simple but powerful API. Because it offers a Clojure and Java client you can read the configuration directly from your application without using intermediate storage such host filesystem, environment variables etc. The best way to pass certificates and other secrets to your applications. Best way to manage application configuration on AWS in general.


inactive stable production use-it

Optimus is a key-value store which I co-designed and developed while working at It has customizable backends, it defaults to DynamoDB and it offers the ability to load millions of records and atomically publish them. This is used to publish Machine Learning models, or pre-computed values like recommendations in a way that the consumer will either see the new set of values or the old set of values, but never some values from two different partial updates. It provides also APIs to quickly and atomically rollback to a previous published version in case you realize that the new Machine Learning model isn’t performing as you expect.


active stable production use-it stars

where is a small Clojure/ClojureScript library to write predicate functions which are easier to read and easier to compose. It supports a number of built-in comparators which are nil safe and they support case insensitive checks.


active stable production use-it stars

viooh-mirror is an Apache Kafka replication tool. It replicates selected topics from a source cluster into a destination cluster and it replicates associated schemas (from Schema-Registry) as well. It turns out that most of the replication tools available out there they either don’t replicate the schemas or, if the do the don’t preserve the ordering of the schemas as they appear in the source cluster. Viooh-mirror solves that problem. When it replicates a topic ensures that the destination subjects has all the same schemas in the same order. This is a tool which I designed and contributed into the development while working on a Real-Time datalake solution. This solution was developed using Continuous Chaos-Testing, it is fairly robust and it has already replicated over 1 trillion messages across a number of clusters.


inactive stable production hold-on stars

Samsara is a Real-Time analytics platform written in Clojure.

It’s is a large scale analytics platform for BigData. With this project I’m targeting users who feel the need of data analytics and they want to keep their data, as supposed to use a third-party service which it just shows you aggregated reports and not the raw data.

It can be used on both: website and mobile apps, but also in backend services. Samsara provides a end-to-end solution for collecting, ingesting, processing, enrich, query and visualize your data leveraging well established Open Source solutions like Kafka and ElasticSearch.

It has been used in large scale deployments processing over 685 million events per day, and 25 million events per hour in peak time, and over 500K clients.

Because of it’s flexible and scalable processing system you can build easily real-time solutions for your products/services. I’ve used it to build a real-time recommendation system and other machine learning solutions.

I’m looking to expand this project with more out-of-the-box machine learning modules and to create a community behind the project.


inactive feature-complete production use-it stars

An idiomatic Clojure driver for Sophia DB. Sophia is RAM-Disk hybrid storage designed to provide best possible on-disk performance without degradation in time. Sophia is an embedded key/value store which implements a LSM storage system. Very fast and fully ACID (Serialized Snapshot Isolation - SSI) transactional support..


inactive mvp production check-it-out stars

A library to boost performances of Clojure web applications with off-heap serverside caching. Serverside caching is uniquely positionated for effective caching it does NOT require all clients to implement caching directives on the client side. The cached payload is stored off-heap and on disk so that it doesn’t put more pressure on the Garbage Collector. Since the cache data is stored on disk it avoid the problem of a cold-restart with and empty cache. The caching logic can be completely customized to tailor your needs.


maintenance-only stable production use-it stars

TrackIt! allows you to instrument your code and record useful metrics and publish those metrics to a number of backend systems for indexing and visualization, such as:

  • Console
  • Ganglia
  • Graphite
  • Statsd
  • Infuxdb
  • Reimann
  • NewRelic
  • AWS Cloudwatch
  • Prometheus
  • JMX Beans

It is based on the popular Dropwizard’s Metrics library, with a Clojure idiomatic and developer friendly API.

If you are thinking to use this, maybe you should check μ/log out first!

Clojure meets GraalVM


GraalVM is really exciting news for Clojure. Particularly the ability to build native images. In this project I’ve tried to collect all the info to build native-images for Clojure based projects. Building complex projects in GraalVM’s native-image can be quite challenging. Therefore, I’ve tried to take common libraries and build hello-world style projects and build them with GraalVM’s native-image and document challenges, parameters to use and solution to common problems. If you are interested in native images for your Clojure projects this is a good place to start.


stable stable production use-it stars

easy-subnet is a command line tool for easily splitting a network range into subnets. You can describe the desired network layout and easy-subnet will return subnet ranges and masks according to the desired layout. It will also provides a list of unused network ranges.


inactive mvp not-in-use hold-on

dragonfiles is a Clojure tools to easily process files. Most of people are familiar with the Linux tool awk. Although very powerful it lack of expressiveness. I found myself having to process several hundreds of thousands of small files and I was trying to decide whether it would have been better to build a shell-scripting solution or a Hadoop-based solution. I wanted something easy as shell scripting, and not so heavy as Hadoop. So I decided to write a small tool to cover this middle ground where it would be too complex to develop awk scripts but not yet so big enough to move to a BigData solution. The tool allow to easily define a processing function which is applied to every file in input at once or line-by-line. You can harness the power of Clojure together with the rich Java/Clojure libraries ecosystem in a command line environment.

dragonfiles is still work-in-progress but already usable if you really want.