https://dhryniuk.com/journal I design, ship and run cloud platforms, as observable, reproducible and quiet at 3 a.m. as the job needs, without reinventing the wheel. en Sun, 27 Sep 2026 18:05:53 GMT https://dhryniuk.com/journal/why-the-inventory-left-coolify https://dhryniuk.com/journal/why-the-inventory-left-coolify Sun, 27 Sep 2026 09:00:00 GMT personal adr ops k8s obs 26 Apr 2026. Coolify deployed the app fast; backups, logs and alerts were what it could not give me. https://dhryniuk.com/journal/authorisation-moves-back-into-the-app https://dhryniuk.com/journal/authorisation-moves-back-into-the-app Fri, 25 Sep 2026 09:00:00 GMT personal sec adr postgres web 23 Sep 2026. Why the rewrite trades row-level security for one data-access layer and a test suite. https://dhryniuk.com/journal/dropping-supabase-keeping-postgres https://dhryniuk.com/journal/dropping-supabase-keeping-postgres Fri, 25 Sep 2026 09:00:00 GMT personal adr db postgres web 23 Sep 2026. The Next.js rewrite of the parts inventory moves to plain Postgres, Drizzle and Better Auth. https://dhryniuk.com/journal/lora-star-garage-and-mailbox https://dhryniuk.com/journal/lora-star-garage-and-mailbox Fri, 25 Sep 2026 09:00:00 GMT personal iot embedded adr supabase 28 Jul 2025. One hub on Wi-Fi, battery nodes talking to it point to point, for places Wi-Fi does not reach. https://dhryniuk.com/journal/pairing-a-sensor-with-no-screen https://dhryniuk.com/journal/pairing-a-sensor-with-no-screen Fri, 25 Sep 2026 09:00:00 GMT personal sec iot embedded 28 Jul 2025. A hub key that never leaves the chip, a household key handed out at pairing, revocation by deleting a row. https://dhryniuk.com/journal/panel-driver-to-an-esp32 https://dhryniuk.com/journal/panel-driver-to-an-esp32 Fri, 25 Sep 2026 09:00:00 GMT personal embedded hw 27 Jul 2025. From Good Display's Arduino sample to a PlatformIO project, and an adapter board of my own. https://dhryniuk.com/journal/appwrite-morning-supabase-afternoon https://dhryniuk.com/journal/appwrite-morning-supabase-afternoon Fri, 25 Sep 2026 09:00:00 GMT personal supabase web embedded 24 Jun 2025. The e-ink frame renderer, built twice in one day on two backends. https://dhryniuk.com/journal/render-on-server-draw-on-device https://dhryniuk.com/journal/render-on-server-draw-on-device Fri, 25 Sep 2026 09:00:00 GMT personal adr embedded iot 23 Jun 2025. The e-ink device fetches a finished picture; the server does the layout. https://dhryniuk.com/journal/colour-eink-decides-the-chip https://dhryniuk.com/journal/colour-eink-decides-the-chip Fri, 25 Sep 2026 09:00:00 GMT personal embedded hw adr 18 Jun 2025. A six-colour panel needs PSRAM, a dual-core ESP32-S3 and patience on every refresh. https://dhryniuk.com/journal/first-backend-on-a-rented-vps https://dhryniuk.com/journal/first-backend-on-a-rented-vps Fri, 25 Sep 2026 09:00:00 GMT personal ops sec net 18 Jun 2025. Two Hetzner servers, keys-only SSH and an admin console behind Zero Trust, ten months before the cluster. https://dhryniuk.com/journal/first-colours-on-a-spectra-6-panel https://dhryniuk.com/journal/first-colours-on-a-spectra-6-panel Fri, 25 Sep 2026 09:00:00 GMT personal embedded hw 9 Jan 2024. A four-inch six-colour e-paper panel on the bench, eighteen months before the device had a name. https://dhryniuk.com/journal/pettrack-field-check https://dhryniuk.com/journal/pettrack-field-check Fri, 25 Sep 2026 09:00:00 GMT personal iot hw flutter firebase python mobile 23 Mar 2022. The check a bench cannot do: a real GPS fix on a city street, seen on Android and iOS at once. https://dhryniuk.com/journal/live-video-pi-over-lte https://dhryniuk.com/journal/live-video-pi-over-lte Fri, 25 Sep 2026 09:00:00 GMT personal iot embedded hw python firebase 31 Jul 2021. Let the camera's encoder do the video; the stream that stayed ran at a sixth of the first bitrate. https://dhryniuk.com/journal/two-languages-one-json-contract https://dhryniuk.com/journal/two-languages-one-json-contract Wed, 23 Sep 2026 09:00:00 GMT work web flutter java aws serverless 4 Oct 2024. A drag-and-drop layout editor in Flutter web, with Java Lambdas doing the heavy work. https://dhryniuk.com/journal/decommissioning-without-deleting-docs https://dhryniuk.com/journal/decommissioning-without-deleting-docs Fri, 18 Sep 2026 09:00:00 GMT personal ops k8s 9 Jun 2026. A clean decommission checklist, including what lives outside the repository. https://dhryniuk.com/journal/restore-that-broke-logins https://dhryniuk.com/journal/restore-that-broke-logins Fri, 18 Sep 2026 09:00:00 GMT personal db ops postgres supabase 11 May 2026. A restore without ownership, and the confusing pair of errors it produces. https://dhryniuk.com/journal/first-app-on-the-cluster https://dhryniuk.com/journal/first-app-on-the-cluster Fri, 18 Sep 2026 09:00:00 GMT personal k8s ops supabase 7 May 2026. The components inventory live on k3s, with the exact list of what went wrong. https://dhryniuk.com/journal/backups-that-restore-nothing https://dhryniuk.com/journal/backups-that-restore-nothing Fri, 18 Sep 2026 09:00:00 GMT personal db ops postgres 6 May 2026. A backup job that exited 0 and restored zero rows, and the drill that caught it. https://dhryniuk.com/journal/systemd-resolved-breaks-coredns https://dhryniuk.com/journal/systemd-resolved-breaks-coredns Fri, 18 Sep 2026 09:00:00 GMT personal net k8s 6 May 2026. The second of two Hetzner and Ubuntu 24.04 traps; short and easy to miss. https://dhryniuk.com/journal/adr-defer-cloudnativepg https://dhryniuk.com/journal/adr-defer-cloudnativepg Fri, 18 Sep 2026 09:00:00 GMT personal adr db k8s postgres 4 May 2026. Bundled Postgres per project for now, with written triggers to revisit. https://dhryniuk.com/journal/four-vms-one-cluster https://dhryniuk.com/journal/four-vms-one-cluster Fri, 18 Sep 2026 09:00:00 GMT personal k8s iac obs 26 Apr 2026. The start of the self-hosted platform every later entry runs on. https://dhryniuk.com/journal/fifty-minutes-after-coolify https://dhryniuk.com/journal/fifty-minutes-after-coolify Fri, 18 Sep 2026 09:00:00 GMT personal ops web flutter supabase 27 Nov 2025. Five fixes for Flutter web behind nginx, each a reusable gotcha. https://dhryniuk.com/journal/let-rls-do-the-filtering https://dhryniuk.com/journal/let-rls-do-the-filtering Fri, 18 Sep 2026 09:00:00 GMT personal sec db supabase postgres 27 Nov 2025. Moving authorisation from the client into the database, and the code that disappeared. https://dhryniuk.com/journal/flatten-the-architecture https://dhryniuk.com/journal/flatten-the-architecture Fri, 18 Sep 2026 09:00:00 GMT personal adr web flutter supabase 31 Jul 2025. An honest ADR on removing abstraction from a small app. https://dhryniuk.com/journal/dev-and-prod-on-amplify-branches https://dhryniuk.com/journal/dev-and-prod-on-amplify-branches Fri, 18 Sep 2026 09:00:00 GMT personal aws amplify ops 24 Jan 2025. Environment promotion for a serverless app done by branch merges. https://dhryniuk.com/journal/myspool-web-amplify https://dhryniuk.com/journal/myspool-web-amplify Fri, 18 Sep 2026 09:00:00 GMT personal aws amplify web flutter python serverless 7 Sep 2024. A second-generation rewrite with a collaborator on the backend. https://dhryniuk.com/journal/price-tags-on-device-ocr https://dhryniuk.com/journal/price-tags-on-device-ocr Fri, 18 Sep 2026 09:00:00 GMT learning mobile flutter learn 18 Feb 2022. A one-week, two-person Flutter experiment with on-device text recognition. https://dhryniuk.com/journal/myspool-mobile-1-0 https://dhryniuk.com/journal/myspool-mobile-1-0 Fri, 18 Sep 2026 09:00:00 GMT personal ops mobile flutter 13 Dec 2021. Thirteen months and ninety versioned builds for a solo mobile release. https://dhryniuk.com/journal/ble-provisioned-wifi-esp32 https://dhryniuk.com/journal/ble-provisioned-wifi-esp32 Fri, 18 Sep 2026 09:00:00 GMT learning embedded iot firebase learn 3 Nov 2021. The first microcontroller project, and the device side of a problem the sensor app solved another way. https://dhryniuk.com/journal/mqtt-spike-to-robot-dashboard https://dhryniuk.com/journal/mqtt-spike-to-robot-dashboard Fri, 18 Sep 2026 09:00:00 GMT personal iot mobile flutter 8 Jul 2021. Prove the transport in a throw-away app, then wire the UI. https://dhryniuk.com/journal/push-on-firebase https://dhryniuk.com/journal/push-on-firebase Fri, 18 Sep 2026 09:00:00 GMT personal aws firebase adr flutter mobile 10 May 2021. A two-cloud setup chosen for one feature, and what it costs in configuration. https://dhryniuk.com/journal/clone-or-parametrise https://dhryniuk.com/journal/clone-or-parametrise Fri, 18 Sep 2026 09:00:00 GMT personal web adr php 21 Jan 2021. Copy-per-model was the fast choice for a four-month job; here is what it cost. https://dhryniuk.com/journal/cognito-via-amplify https://dhryniuk.com/journal/cognito-via-amplify Fri, 18 Sep 2026 09:00:00 GMT personal aws amplify adr flutter mobile 7 Nov 2020. The first managed-auth decision, and the CloudFormation that came with it. https://dhryniuk.com/journal/switching-to-flutter https://dhryniuk.com/journal/switching-to-flutter Fri, 18 Sep 2026 09:00:00 GMT personal mobile flutter adr 19 Oct 2020. An eight-day onboarding prototype that decided the next five years of mobile work. https://dhryniuk.com/journal/exploded-view-drawings-as-image-maps https://dhryniuk.com/journal/exploded-view-drawings-as-image-maps Fri, 18 Sep 2026 09:00:00 GMT personal web php 17 Sep 2020. How a catalogue with hundreds of drawings was made navigable without a CMS. https://dhryniuk.com/journal/six-days-of-camfix-builds https://dhryniuk.com/journal/six-days-of-camfix-builds Fri, 18 Sep 2026 09:00:00 GMT personal embedded hw ops android mobile 28 Jul 2020. Eight builds to stabilise a USB camera on a tablet; the final fix was one line. https://dhryniuk.com/journal/react-native-rhyme-finder https://dhryniuk.com/journal/react-native-rhyme-finder Fri, 18 Sep 2026 09:00:00 GMT personal mobile learn android 14 Jul 2020. Second store app, two months after the first, and the only React Native project. https://dhryniuk.com/journal/first-google-play-release https://dhryniuk.com/journal/first-google-play-release Fri, 18 Sep 2026 09:00:00 GMT personal mobile android learn 11 May 2020. A Kotlin age calculator: five days of code, a public listing eight days after the first commit. https://dhryniuk.com/journal/one-branch-per-tablet-generation https://dhryniuk.com/journal/one-branch-per-tablet-generation Fri, 18 Sep 2026 09:00:00 GMT personal embedded adr mobile android 11 Feb 2020. Branching by hardware target: what it cost in merges and why alpha suffixes replaced versions. https://dhryniuk.com/journal/three-lessons-three-languages https://dhryniuk.com/journal/three-lessons-three-languages Fri, 18 Sep 2026 09:00:00 GMT personal mobile android ideas 27 Nov 2019. Localising a content-heavy app early is cheap; retrofitting is not. https://dhryniuk.com/journal/first-ble-lab-sensor https://dhryniuk.com/journal/first-ble-lab-sensor Fri, 18 Sep 2026 09:00:00 GMT personal iot embedded mobile android 12 Oct 2019. The first hardware-in-the-loop code I shipped, nine days after the first commit, on a science tablet with its own sensor port. https://dhryniuk.com/journal/wait-on-quota https://dhryniuk.com/journal/wait-on-quota Thu, 17 Sep 2026 09:00:00 GMT work gcp benchmarking ops 15 Sep 2026. Quota as a scheduling signal rather than an error. https://dhryniuk.com/journal/vendor-feed-empty https://dhryniuk.com/journal/vendor-feed-empty Thu, 17 Sep 2026 09:00:00 GMT work ops data 23 Aug 2026. A weekly refresh that trusted an upstream feed, and the abort gate it earned. https://dhryniuk.com/journal/chart-that-printed-blank https://dhryniuk.com/journal/chart-that-printed-blank Thu, 17 Sep 2026 09:00:00 GMT work web ops node 23 Jun 2026. A race between chart animation and a screenshot, diagnosed from both sides in one day. https://dhryniuk.com/journal/two-stacks-one-bucket https://dhryniuk.com/journal/two-stacks-one-bucket Thu, 17 Sep 2026 09:00:00 GMT work aws cdk iac s3 26 May 2026. Two CDK stacks configuring one bucket overwrite each other silently. https://dhryniuk.com/journal/one-launch-script https://dhryniuk.com/journal/one-launch-script Thu, 17 Sep 2026 09:00:00 GMT work aws benchmarking bash 13 Feb 2026. Replacing a per-instance script matrix with detection at boot. https://dhryniuk.com/journal/fleet-that-launches-itself https://dhryniuk.com/journal/fleet-that-launches-itself Thu, 17 Sep 2026 09:00:00 GMT work aws benchmarking ops bash 6 Feb 2026. What has to be in user-data for a machine to finish a job with nobody watching. https://dhryniuk.com/journal/which-failures-block https://dhryniuk.com/journal/which-failures-block Thu, 17 Sep 2026 09:00:00 GMT work data ops aws serverless 19 Jan 2026. How a hard validation gate turned into a warning, and why that was right. https://dhryniuk.com/journal/rollback-added-then-muted https://dhryniuk.com/journal/rollback-added-then-muted Thu, 17 Sep 2026 09:00:00 GMT work data aws ops 8 Jan 2026. Why a rollback that runs on every failure can be worse than none. https://dhryniuk.com/journal/llm-call-behind-a-queue https://dhryniuk.com/journal/llm-call-behind-a-queue Thu, 17 Sep 2026 09:00:00 GMT work llm aws serverless 7 Oct 2025. A model call is too slow for a request-response API behind a gateway timeout. https://dhryniuk.com/journal/retiring-lambdas-restore-path https://dhryniuk.com/journal/retiring-lambdas-restore-path Thu, 17 Sep 2026 09:00:00 GMT work aws ops serverless 18 Sep 2025. Archive, verify, delete, keep a way back. https://dhryniuk.com/journal/the-sax-day https://dhryniuk.com/journal/the-sax-day Thu, 17 Sep 2026 09:00:00 GMT work java perf ops etl 21 Jul 2025. A streaming parser rolled back and re-landed in one day. https://dhryniuk.com/journal/notebook-becomes-a-lambda https://dhryniuk.com/journal/notebook-becomes-a-lambda Thu, 17 Sep 2026 09:00:00 GMT work aws serverless python 30 Jun 2025. What has to change for an analyst's notebook to run as a production handler. https://dhryniuk.com/journal/reverting-the-revert https://dhryniuk.com/journal/reverting-the-revert Thu, 17 Sep 2026 09:00:00 GMT work java etl 13 Aug 2024. A new union approach, reverted, then re-applied the same evening. https://dhryniuk.com/journal/climbing-the-heap https://dhryniuk.com/journal/climbing-the-heap Thu, 17 Sep 2026 09:00:00 GMT work java jvm perf ops 24 May 2024. How a workbook engine eats memory, and where the real limit was. https://dhryniuk.com/journal/visual-regression-before-release https://dhryniuk.com/journal/visual-regression-before-release Thu, 17 Sep 2026 09:00:00 GMT work qa aws ops serverless web node 26 Feb 2024. Screenshot diffs before every release, and why partial results mattered more than a perfect diff. https://dhryniuk.com/journal/excel-engine-moves-to-java https://dhryniuk.com/journal/excel-engine-moves-to-java Thu, 17 Sep 2026 09:00:00 GMT work java aws fargate etl adr 20 Nov 2023. From Node Lambdas to a Spring Boot container on Fargate, and why. https://dhryniuk.com/journal/lambda-outgrows-itself https://dhryniuk.com/journal/lambda-outgrows-itself Thu, 17 Sep 2026 09:00:00 GMT work aws serverless etl node 13 Jun 2023. How a function grows to thousands of lines, and what that costs. https://dhryniuk.com/journal/dlq-first-real-failure https://dhryniuk.com/journal/dlq-first-real-failure Thu, 17 Sep 2026 09:00:00 GMT work aws serverless ops 7 Jun 2023. A dead-letter handler is only tested when things fail. https://dhryniuk.com/journal/intake-pipeline-shape https://dhryniuk.com/journal/intake-pipeline-shape Thu, 17 Sep 2026 09:00:00 GMT work aws serverless etl node 29 Jul 2022. Validate, clean, process: the pipeline shape that every later version kept. https://dhryniuk.com/journal/leading-zeros-and-exponents https://dhryniuk.com/journal/leading-zeros-and-exponents Thu, 17 Sep 2026 09:00:00 GMT work etl data node 9 Dec 2021. Numbers that are really strings, met in the first month and never forgotten. https://dhryniuk.com/journal/stop-hand-parsing-formulas https://dhryniuk.com/journal/stop-hand-parsing-formulas Thu, 17 Sep 2026 09:00:00 GMT work etl data node 24 Nov 2021. The week a home-grown formula evaluator stopped paying for itself.