Newest first, grouped by year. Search or filter by topic.
JSON payloads can migrate lazily because the reader controls the shape - relational rows cannot, because the table is the shape. VersionKit's EF Core answer is table-per-version - archive Orders as Orders_v2 on a schema bump, track every row's home in a registry, and let old rows stay old until something moves them. Part 7 of the Entity Versioning with VersionKit series.
Thirteen repositories, one umbrella that runs twelve of them, two interchangeable API gateways and a service that watches everything - the Pacco estate read as a system of systems, and the fifteen-part series it earns.
Seeker, initializer, processor, post-processor - Chronicle's whole runtime is four internal classes you can read in ten minutes. A source walk through the pipeline, including the gate that drops messages, the finally block that always persists, and the state that isn't as final as it looks.
The series retrospective - Pacco's domain teaches real rules (state machines, priority expropriation, loyalty ladders, compensations) on top of cardboard data (bare-decimal prices, one vehicle per order, size-cube parcels, no payment, and a capacity check that ships in two halves nobody ever connects). What to steal, what to distrust, and what fourteen parts of source-reading add up to.
KC Star V5 climbs the org chart in a single view - employee to office to region to organisation - and a stored procedure that materialises the rollups. Commission analysis and quote-to-delivery ratios fall out of the same hierarchy.
How one Terraform template models an entire Event Hubs estate as nested lookup maps - hubs, capture, boolean-triplet authorization rules and consumer groups - and the type-unification trap hiding in its empty environments. Part 6 of the Terraform Module Catalog.
AssignVehicleToOrder is the one command in Pacco that cannot finish alone - Orders calls Vehicles, then Pricing, and Pricing calls Customers, a synchronous enrichment chain on the write path of a messaging estate. At the end of it sits a deliberately bus-less calculator with a loyalty ladder, an unassigned Id and a discount logged in dollars.
FastEndpoints wires FluentValidation into the pipeline by request-DTO type, runs validators as singletons, and shares one failure list between binder, validator and handler. The lifetime rule is the part that bites. Part 5 of FastEndpoints in Depth.
Availability guards every save with a version-filtered ReplaceOneAsync - and discards the result, so a lost update is indistinguishable from a successful one and the integration event ships either way. Three folders away, Orders and Customers inherit the same AggregateRoot name with the versioning quietly deleted.
KC Star V4 tracks lineage two incompatible ways depending on which build you run - a normalized FactLineage graph in the root file, a denormalized DataLineage string in the version folder. The fork is real, and it is a clean case study in when a graph pays and when a string is enough.
In Pacco the CQRS split is not a diagram - it is wiring you can read. Every command arrives through two front doors, RabbitMQ subscription and controller-less HTTP dispatch, while queries ride HTTP only; commands assign their own ids in the constructor, and a marker attribute turns each service into its own runtime contract registry.
Deleting a tenant is the most dangerous button in the platform — behind it sit DROP SCHEMA CASCADE and DROP DATABASE. A two-step lifecycle with global query filters, a SaveChanges interception and an explicit purge keeps the blast radius survivable.
V3's rewritten CreateAggregatedFacts expires every aggregate and rebuilds them all from scratch on each run. It is blunt, it is correct, and the trade between rebuild-it-all simplicity and incremental cleverness is one KC Star kept relitigating all the way to V8.
KC Star V9 Simplified's schema is four permission tables and five seeded personas - full access, online-only, store-only, delivery-and-quotes, commission-only. GetFilteredSalesData takes an employee and returns exactly their slice. Permissions you can read in one table.
Every Pacco service that enables Convey's Mongo outbox also sets disableTransactions to true - the aggregate write and the outbox write are separate operations, the pattern's one guarantee switched off in configuration. Meanwhile the inbox that would absorb the resulting duplicates sits beside three handlers that throw on them.
One static registration method wires the whole discovery subsystem into an Azure Functions host, and one CI pipeline packs it as a private NuGet package. The lifetime choices in those few lines quietly decide the caching semantics of the entire estate - and a duplicate registration teaches how DI forgives. Part 5 of Service Discovery Without a Service Mesh.
Four Pacco services need customer data and no two agree on how to get it - Orders and Parcels keep id-only replicas fed by events, Availability phones home mid-command, and Pricing pulls the full details document to count one number. One upstream, three consistency stances, five representations of the same entity.
KC Star V2's measure formulas read like window functions - SUM(...) OVER (PARTITION BY SaleType) - but the implementation is plain GROUP BY. Here is how CreateAggregatedFacts actually builds the aggregates, and why the formula strings deliberately lie.
Inside the Customers service a registration completes - and the rest of the estate hears that a customer was created. Three lines of EventMapper perform the best ubiquitous-language translation in Pacco, sitting on top of a lifecycle state machine with one guarded transition and four administrative jumps.
Fusing per-employee permissions with per-change recalculation multiplies work by headcount. KC Star V9 ships both the naive per-employee implementation and an optimised per-permission-group one that collapses a thousand employees into seven groups. The most important design call in the version.
With no terraform_remote_state anywhere in 230 stacks, every cross-stack reference in this Azure estate was a literal name string - a taxonomy you could read from ls, a coupling with zero runtime dependencies, and a silent-drift hazard on every rename. Part 7 of the Terraform on Azure series.
Order.DeleteParcel raises a ParcelDeleted event and never removes the parcel from the set, while Parcels' cancel and delete handlers detach exactly one parcel of many. Two bounded contexts maintain the same association independently, both with bugs, and end up permanently disagreeing about a fact.
How a pact travels from the consumer's pipeline to the provider's - Pactify's file and HTTP publishers, Pact Broker URL anatomy, and the unchecked response status that makes a failed publish silently pass your build.
Convey's IRejectedEvent gives Pacco an application-level negative acknowledgement - a rejected twin for every command. Reading the four exception-to-message mappers shows the pattern decaying in four different ways, from a failed reserve announced as a failed release to rejection classes nothing ever constructs.
KC Star V1 has no ETL job and no application code. Two PostgreSQL triggers explode sales into dimension rows and version them on change - and the gaps between what they do and what I claimed they do are the most instructive part of V1.
