Monthly Archives: Juli 2020

Raspbian SSH Server fails after upgrade from Stretch to Buster (no SSH connection)

I used this excellent guide to update my Raspbian from Stretch to Buster:https://pimylifeup.com/upgrade-raspbian-stretch-to-raspbian-buster/After rebooting my Pi, the SSH connection was gone. Logging into the Pi using the attached keyboard and monitor allowed me to debug the issue:service ssh statusjournalctl -u ssh -n 200"Missing privilege separation directory /run/sshd"This directory needs to be created at startup for [...]

By | Juli 31st, 2020|Raspberry Pi Blog|Kommentare deaktiviert für Raspbian SSH Server fails after upgrade from Stretch to Buster (no SSH connection)

How to set unique object ids in embedded documents across a MongoDB collection

MongoDB’s updateMany can be used to update all documents which are matched. ProblemIf, however, you want to set unique new ObjectIDs in your update, you would find that MongoDB sets the same ObjectID for every entry:db.getCollection('mypis_collectedpis').updateMany({}, {$set:      {apps: {         "com.picockpit/core": {             meta: {                 version: "2.0",                 name: "PiCockpit Core",                 image: "",                 description: "PiCockpit.com core application"                 [...]

By | Juli 24th, 2020|MongoDB|Kommentare deaktiviert für How to set unique object ids in embedded documents across a MongoDB collection

switching from JSON to MsgPack in a backwards compatible manner with Paho MQTT (JavaScript)

picockpit.com makes heavy use of MQTT. For the upcoming version 2.0 I have decided to switch it to MsgPack.Why MsgPack?MsgPack (actually called MessagePack – packages tend to use MsgPack) is a binary format, aimed at compatibility with JSON, but decreasing file size (which is good for saving bandwidth & server resources).Another advantage: MessagePack allows you [...]

By | Juli 21st, 2020|JavaScript, MQTT|Kommentare deaktiviert für switching from JSON to MsgPack in a backwards compatible manner with Paho MQTT (JavaScript)

Stupid business mistakes #6 :: No clear call to action (button)

A friend forwarded me an email, asking me (and other undisclosed recipients) to sign a petition to continue German support for Nepal.I decided to support her and her cause, spending a minute of my time on this.But this minute turned into this blogpost. And it has a valuable lesson for all of us:if people actually [...]

By | Juli 3rd, 2020|Stupid business mistakes|Kommentare deaktiviert für Stupid business mistakes #6 :: No clear call to action (button)