• Golang: Managing the Garbage Collector settings

  3 min read

  
  

  In Golang, there are two environment variables that can be used to manage the Garbage Collector in Go: GOGC and GOMEMLIMIT. With these variables, you can control how often the garbage collector runs and set an overall memory limit that the Go runtime can use.

  05/11/2024

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• Golang: Using the Garbage Collection tracing

  3 min read

  
  

  Go is a garbage-collected language: It will reclaim any unused memory. This automation can sometimes introduce performance challenges. We can use the GODEBUG environment variable to provide insights into specific internal operations of the Go runtime, such as scheduling, memory allocation, and garbage collection.

  30/10/2024

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• Create a JSON object using a cli tool: jq

  1 min read

  
  

  We can define jq tool as what's sed but for JSON data: We can use it for multiple purposes, for example to create a valid JSON object.

  Let's assume we want to create a JSON containing a multi-line string, we can simulate it like follows or just use some file with cat:

  $ echo -e "multi\nline"
  multi
  line
  

  07/12/2022

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• nmap: List only open ports while scanning

  2 min read

  
  

  While scanning using nmap a network for a specific port (using the -p option), it can be confusing toe get a list of hosts that are alive with either closed or filtered ports while we only care for open ports:

  $ sudo nmap -sS 10.12.16.0/24 -p 8123
  Starting Nmap 7.80 ( https://nmap.org ) at 2022-12-04 18:18 CET
  Nmap scan report for _gateway (10.12.16.1)
  Host is up (0.0010s latency).
  
  PORT     STATE  SERVICE
  8123/tcp filtered polipo
  MAC Address: CD:44:F0:F4:22:44 (Unknown)
  
  Nmap scan report for 10.12.16.10
  Host is up (0.00020s latency).
  
  PORT     STATE SERVICE
  8123/tcp open  polipo
  MAC Address: DC:A6:33:77:AA:BB (Raspberry Pi Trading)
  
  Nmap scan report for 10.12.16.33
  Host is up (0.00046s latency).
  
  PORT     STATE  SERVICE
  8123/tcp closed polipo
  MAC Address: B8:27:EB:8D:99:11 (Raspberry Pi Foundation)
  
  (...)
  
  Nmap done: 256 IP addresses (15 hosts up) scanned in 1.78 seconds
  

  05/12/2022

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• Troubleshooting Spinnaker: Rosco Bakes

  2 min read

  
  

  If we have a baking stage failing that we cannot get our heads around, it might help to be able to retieve some extra information about it. We can get more details about connecting to the redis instance that rosco uses.

  01/06/2022

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