What's inside My Vaccine Pass? (Part 1)

When they were talking about how vaccine passports might work, I had an idea of how I'd make such a system. A QR code with some information about each person and their vaccination status, a signature signed with the private key of the issuer, and a way for people to verify that signature with the issuer's public key.

Why does Docker restart all containers regularly?

For as long as I can remember, every now and then, all my Docker containers restart. I had no idea why. I am running Ubuntu 16.04 LTS (Xenial). I got the exact start time of my containers like so: docker inspect --format='{{.State.StartedAt}}' <CONTAINERID> (Thanks to Tim Robinson for that bit of magic.) Then I looked in the syslog for entries around that date. (I used lnav to make that a bit easier to do.

View a config file without comments

Sometimes you have a config file that has is heavily annotated (which is great). But sometimes you just want to see the actual configuration without all that help text. Use grep’s -v (invert) option: cat config | grep -v \# (Note that the # has to be escaped.)

Importing a Maildir using Dovecot

I’m looking into using Dovecot as a way to store all my old emails (I have emails going back 20 years would you believe!) Before I commit to it though, I am testing how easy it is to migrate between servers. To import the contents of one Maildir into Dovecot, use the following: doveadm -Dv import maildir:<path> "" all Where: -Dv means verbose debugging. You don’t need that. maildir:<path> tells Dovecot where to get the emails from, and that they’re in the Maildir format.

Re-signing an Enterprise iOS app

If you have an in-house app that you’ve distributed across your organisation as part of the iOS Enterprise program, you may find that the app stops working or installing. This is likely because your provisioning profile and/or certificate has expired. If you look at the console (in Xcode, Devices), you’ll see something like: Apr 26 15:05:58 iPad amfid[3086] <Error>: SecTrustEvaluate [leaf IssuerCommonName SubjectCommonName] Apr 26 15:05:58 iPad amfid[3086] <Error>: /private/var/mobile/Containers/Bundle/Application/256F1EAD-8F72-49CA-AC96-A50CD52F788A/MyApp.app/MyApp not valid: 0xe8008015: A valid provisioning profile for this executable was not found.

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