diff options
| -rw-r--r-- | blog/entry/gnus+notmuch.mdwn | 103 | ||||
| -rw-r--r-- | blog/entry/rpi4-consfigurator.mdwn | 113 | ||||
| -rw-r--r-- | index.mdwn | 2 | ||||
| -rw-r--r-- | philos/teaching/philos.mdwn | 7 | ||||
| -rw-r--r-- | tech/code/consfigurator.mdwn | 3 | ||||
| -rw-r--r-- | tech/machines.mdwn | 32 |
6 files changed, 245 insertions, 15 deletions
diff --git a/blog/entry/gnus+notmuch.mdwn b/blog/entry/gnus+notmuch.mdwn new file mode 100644 index 0000000..bae4055 --- /dev/null +++ b/blog/entry/gnus+notmuch.mdwn @@ -0,0 +1,103 @@ +[[!tag Emacs notmuch]] + +I'd like to share some pointers for using Gnus together with notmuch rather +than notmuch together with notmuch's own Emacs interface, notmuch.el. I set +about this because I recently realised that I had been poorly reimplementing +lots of Gnus features in my init.el, primarily around killing threads and +catching up groups, supported by a number of complex shell scripts. I've now +switched over, and I've been able to somewhat simplify what's in my init.el, +and drastically simplify my notmuch configuration outside of Emacs. I'm +always more comfortable with less Unix and more Lisp when it's feasible. + +- The basic settings are `gnus-search-default-engines` and + `gnus-search-notmuch-remove-prefix`, explained in `(info "(gnus) Searching")`, + and an entry for your maildir in `gnus-secondary-select-methods`, explained + in `(info "(gnus) Maildir")`. Then you will have `G G` and `G g` in the + group buffer to make and save notmuch searches. + +- I think it's important to have something equivalent to + `notmuch-saved-searches` configured programmatically in your init.el, rather + than interactively adding each saved search to the group buffer. This is + because, as notmuch users know, these saved searches are more like + permanent, virtual inboxes than searches. You can learn how to do this by + looking at how `gnus-group-make-search-group` calls `gnus-group-make-group`. + I have some code running in `gnus-started-hook` which does something like + this for each saved search: + + ``` {.el} + (if (gnus-group-entry group) + (gnus-group-set-parameter group 'nnselect-specs ...) + (gnus-group-make-group ...)) + ``` + + The idea is that if you update your saved search in your init.el, + rerunning this code will update the entries in the group buffer. An + alternative would be to just kill every nnselect search in the group + buffer each time, and then recreate them. In addition to reading + `gnus-group-make-search-group`, you can look in `~/.newsrc.eld` to see the + sort of `nnselect-specs` group parameters you'll need your code to + produce. + + I've very complicated generation of my saved searches from some variables, + but that's something I had when I was using notmuch.el, too, so perhaps + I'll describe some of the ideas in there in another post. + +- You'll likely want to globally bind a function which starts up Gnus if it's + not already running and then executes an arbitrary notmuch search. For that + you'll want `(unless (gnus-alive-p) (gnus))`, and **not** + `(unless (gnus-alive-p) (gnus-no-server))`. This is because you need Gnus + to initialise nnmaildir before doing any notmuch searches. Gnus passes + `--output=files` to notmuch and constructs a summary buffer of results by + selecting mail that it already knows about with those filenames. + +- When you're programmatically generating the list of groups, you might also + want to programmatically generate a topics topology. This is how you do + that: + + ``` {.el} + (with-current-buffer gnus-group-buffer + (gnus-topic-mode 0) + (setq gnus-topic-alist nil gnus-topic topology nil) + ;; Now push to those two variables. You can also use + ;; `gnus-topic-move-matching' to move nnmaildir groups into, e.g., + ;; "misc". + (gnus-topic-mode 1) + (gnus-group-list-groups)) + ``` + + If you do this in `gnus-started-hook`, the values for those variables Gnus + saves into `~/.newsrc.eld` are completely irrelevant and do not need + backing up/syncing. + +- When you want to use `M-g` to scan for new mail in a saved search, you'll + need to have Gnus also rescan your nnmaildir inbox, else it won't know about + the filenames returned by notmuch and the messages won't appear. This is + similar to the `gnus` vs. `gnus-no-server` issue above. I'm using `:before` + advice to `gnus-request-group-scan` to scan my nnmaildir inbox each time any + nnselect group is to be scanned. + +- If you are used to linking to mail from Org-mode buffers, the existing + support for creating links works fine, and the standard `gnus:` links + already contain the Message-ID. But you'll probably want opening the link + to perform a notmuch search for id:foo rather than trying to use Gnus's own + jump-to-Message-ID code. You can do this using `:around` or `:override` + advice for `org-gnus-follow-link`: look at + `gnus-group-read-ephemeral-search-group` to do the search, and then call + `gnus-summary-goto-article`. + +I don't think that the above is especially hacky, and don't expect changes to +Gnus to break any of it. Implementing the above for your own notmuch setup +should get you something close enough to notmuch.el that you can take +advantage of Gnus' unique features without giving up too much of notmuch's +special features. However, it's quite a bit of work, and you need to be good +at Emacs Lisp. I'd suggest reading lots of the Gnus manual and determining +for sure that you'll benefit from what it can do before considering switching +away from notmuch.el. + +Reading through the Gnus manual, it's been amazing to observe the extent to +which I'd been trying to recreate Gnus in my init.el, quite oblivious that +everything was already implemented for me so close to hand. Moreover, I used +Gnus ten years ago when I was new to Emacs, so I should have known! I think +that back then I didn't really understand the idea that Gnus for mail is about +reading mail like news, and so I didn't use any of the features, back then, +that more recently I've been unknowingly reimplementing. diff --git a/blog/entry/rpi4-consfigurator.mdwn b/blog/entry/rpi4-consfigurator.mdwn new file mode 100644 index 0000000..a0e714f --- /dev/null +++ b/blog/entry/rpi4-consfigurator.mdwn @@ -0,0 +1,113 @@ +[[!meta title="Setting up a single-board desktop replacement with Consfigurator"]] + +The ThinkPad x220 that I had been using as an ssh terminal at home finally +developed one too many hardware problems a few weeks ago, and so I ordered a +Raspberry Pi 4b to replace it. Debian builds [minimal SD +card images](http://raspi.debian.net/) for these machines already, but I +wanted to use the usual ext4-on-LVM-on-LUKS setup for GNU/Linux workstations. +So I used [Consfigurator](/tech/code/consfigurator) to build a custom image. + +There are two key advantages to using Consfigurator to do something like this: + +1. As shown below, it doesn't take a lot of code to define the host, it's + easily customisable without writing shell scripts, and it's all + declarative. (It's quite a bit less code than [Debian's image-building + scripts](https://salsa.debian.org/raspi-team/image-specs), though I haven't + carefully compared, and they are doing some additional setup beyond what's + shown below.) + +2. You can do nested block devices, as required for ext4-on-LVM-on-LUKS, + without writing an intensely complex shell script to expand the root + filesystem to fill the whole SD card on first boot. This is because + Consfigurator can just as easily partition and install an actual SD card as + it can write out a disk image, using the same host definition. + +Consfigurator already had all the capabilities to do this, but as part of this +project I did have to come up with the high-level wrapping API, which didn't +exist yet. My first SD card write wouldn't boot because I had to learn more +about kernel command lines; the second wouldn't boot because of a [minor bug +in Consfigurator regarding +/etc/crypttab](https://git.spwhitton.name/consfigurator/commit/?id=94a10f08b087afa25cd7757e1ad2ad4c9a82f63b); +and the third build is the one I'm using, except that the first boot runs into +a [bug in cryptsetup-initramfs](https://bugs.debian.org/1016455). So as far +as Consfigurator is concerned I would like to claim that it worked on my +second attempt, and had I not been using LUKS it would have worked on the +first :) + +## The code + +``` {.common-lisp} +(defhost erebus.silentflame.com () + "Low powered home workstation in Tucson." + (os:debian-stable "bullseye" :arm64) + (timezone:configured "America/Phoenix") + + (user:has-account "spwhitton") + (user:has-enabled-password "spwhitton") + + (disk:has-volumes + (physical-disk + (partitioned-volume + + ((partition + :partition-typecode #x0700 :partition-bootable t :volume-size 512 + (fat32-filesystem :mount-point #P"/boot/firmware/")) + + (partition + :volume-size :remaining + + (luks-container + :volume-label "erebus_crypt" + :cryptsetup-options '("--cipher" "xchacha20,aes-adiantum-plain64") + + (lvm-physical-volume :volume-group "vg_erebus")))))) + + (lvm-logical-volume + :volume-group "vg_erebus" + :volume-label "lv_erebus_root" :volume-size :remaining + + (ext4-filesystem :volume-label "erebus_root" :mount-point #P"/" + :mount-options '("noatime" "commit=120")))) + + (apt:installed "linux-image-arm64" "initramfs-tools" + "raspi-firmware" "firmware-brcm80211" + "cryptsetup" "cryptsetup-initramfs" "lvm2") + (etc-default:contains "raspi-firmware" + "ROOTPART" "/dev/mapper/vg_erebus-lv_erebus_root" + "CONSOLES" "ttyS1,115200 tty0")) +``` + +and then you just insert the SD card and, at the REPL on your laptop, + +``` {.common-lisp} +CONSFIG> (hostdeploy-these laptop.example.com + (disk:first-disk-installed-for nil erebus.silentflame.com #P"/dev/mmcblk0")) +``` + +There is more general information in the [OS installation +tutorial](https://spwhitton.name/doc/consfigurator/tutorial/os_installation.html) +in the Consfigurator user's manual. + +## Other niceties + +- Configuration management that's just as easily applicable to OS installation + as it is to the more usual configuration of hosts over SSH drastically + improves the ratio of cost-to-benefit for including small customisations one + is used to. + + For example, my standard Debian system configuration properties (omitted + from the code above) meant that when I was dropped into an initramfs shell + during my attempts to make an image that could boot itself, I found myself + availed of my custom [Space Cadet-inspired keyboard + layout](/blog/entry/spacecadetrebindings), without really having thought at + any point "let's do something to ensure I can have my usual layout while I'm + figuring this out." It was just included along with everything else. + +- As compared with the ThinkPad x220, it's nice how the Raspberry Pi 4b is + silent and doesn't have any LEDs lit by default once it's booted. A quirk + of my room is that one plug socket is controlled by a switch right next to + the switch for the ceiling light, so I've plugged my monitor into that + outlet. Then when I've finished using the new machine I can flick that + switch and the desk becomes completely silent and dark, without actually + having to suspend the machine to RAM, thereby stopping cron jobs, preventing + remote access from the office to fetch uncommitted files, etc.. @@ -44,7 +44,7 @@ the [Debian](https://debian.org/) operating system. ## E-mail -`spwhitton@spwhitton.name` / `spwhitton@email.arizona.edu` / `spwhitton@debian.org` +`spwhitton@spwhitton.name` / `spwhitton@arizona.edu` / `spwhitton@debian.org` ## OpenPGP diff --git a/philos/teaching/philos.mdwn b/philos/teaching/philos.mdwn index f0f9784..1700722 100644 --- a/philos/teaching/philos.mdwn +++ b/philos/teaching/philos.mdwn @@ -22,3 +22,10 @@ regularly for updates. concepts that you could not expect such a student to already know -- all of the new concepts introduced by the authors we've been reading in this particular class. + +## Office hours + +1. You do not need to ask for an appointment unless the syllabus says + "by appointment only". Just show up at the times given. + +2. Office hours are for one-on-one help, not group review sessions. diff --git a/tech/code/consfigurator.mdwn b/tech/code/consfigurator.mdwn index c3c7f96..8bc5d8b 100644 --- a/tech/code/consfigurator.mdwn +++ b/tech/code/consfigurator.mdwn @@ -37,7 +37,8 @@ we can out of all that existing distro policy-compliant work! ## Installation and usage ## Please see the [user's manual](https://spwhitton.name/doc/consfigurator/), -which includes a tutorial/quick start guide. +which includes a tutorial/quick start guide. There's also [an introductory +video](https://www.youtube.com/watch?v=CSWaBYCPXO8) for Consfigurator 1.0.3. ## Source code ## diff --git a/tech/machines.mdwn b/tech/machines.mdwn index b71c79b..2985e2a 100644 --- a/tech/machines.mdwn +++ b/tech/machines.mdwn @@ -9,8 +9,8 @@ Active service zephyr : desktop workstation in Sheffield -hephaestus -: desktop workstation in Tucson +erebus +: single-board desktop replacement in Tucson [[melete|https://en.wikipedia.org/wiki/Melete]] : laptop @@ -18,23 +18,17 @@ hephaestus [[coeus|https://en.wikipedia.org/wiki/Coeus]] : personal web, git and file server -- LXC host -dionysus -: tablet computer +leto, rhea +: secondary LXC hosts hermes : smartphone asteria -: secondary DNS - -Semi-active service -=================== +: secondary MX & DNS -poseidon -: Debian Haskell Group build machine, donated by Exoscale - -iris -: laptop 2016--2020, now with hardware issues +dionysus +: tablet computer Retired ======= @@ -62,3 +56,15 @@ artemis hestia : low-powered ARM file server + +poseidon +: Debian Haskell Group build machine, donated by Exoscale + +hephaestus +: desktop workstation in Tucson + +iris +: laptop 2016--2020, ssh terminal with hardware issues 2020--2022 + +boreas +: Pinebook Pro, seemingly bricked |