NiFi Registry in Docker with Git auto-cloning on startup


Running NiFi Registry with Git and auto-cloning on startup is possible with three authentication options:

  1. HTTPS user and password
  2. git+ssh (~/.ssh bind mount)
  3. git+ssh (SSH keys as environment variables)

Publishing Docker image to Docker Hub using Automated builds

Although there are some resources on how to create, label and publish images to, I have found myself in need to put all those pieces together. This article is the complete example of how to create, build and test, label and publish docker image using Automated Builds with source code hosted at

In this article we will:

  • create small docker image, build it and test locally
  • create and link repository with GitHub repository
  • setup automated builds of the image
  • alter the automated builds setup to include build-time labels
  • verify the build

Using Apache NiFi to ingest SNMP tables into Avro

SNMP is a very old protocol, dating back to 1988 and was elaborated later in 90s. When it comes to hardware monitoring, however, nearly every device supports at least SNMPv2. This makes it the “good enough” choice for basic monitoring of devices.

In this article, we create a Apache NiFi data flow, which will collect SNMP tables and convert them into Avro format.

Although there is SNMP processor in NiFi available, we will proceed with different approach, since the processor does not support querying SNMP tables. Steps in this article include:

  • Preparing sandbox environment – simulator for SNMP server, setting up command line tools to grab SNMP tables (ifTable is used as an exapmle)
  • Designing the NiFi DataFlow – step-by-step data flow design instructions to query SNMP server for a table, parse the CSV-like output into Apache Avro format (one record per CSV line).

How to add PBKDF2 password hashing to a Spring Security based project

Although there are some secure password hashing algorithms available, PBKDF2 is not yet implemented in Spring Security. Only BCryptPasswordEncoder, NoOpPasswordEncoder, StandardPasswordEncoder are available in versions 4.0.0.RC1 and 3.2.5.RELEASE.

In this article, we create and use our own PBKDF2 implementation of the PasswordEncoder.