NexusFabricRequest a walkthrough

The platform

NexusFabric is a process that takes messages, runs them through compiled flows, and delivers them onward. This page describes how it is laid out; the chapters at the end go into detail.

A flow is a file, published as an artifact

A flow is written in a file with a header and steps — in a text editor or on the visual canvas in VS Code, where each step is a node — validated from the command line, and published. Publication produces a compiled artifact identified by its fingerprint; what does not compile never reaches runtime.

  • XSLT outside the supported subset is refused at publication, not run some other way.
  • A literal response status outside the valid range is a compile refusal, and therefore a refusal at command-line validation too.
  • There is exactly one way to read a context name in a flow. The second spelling was deleted, not deprecated.

Four doors, one delivery bracket

A message can arrive through a synchronous HTTP call, through the queue, through a schedule, or through the gRPC door. All four pass through the same access gate and the same delivery bracket, so deduplication, correlation and response memoisation are not rewritten per door.

What changes and what does not between inbound doors
DoorAccess gateHow it reads in the log
Synchronous HTTPThe same oneChannel http
QueueAt enqueue timeChannel queue
ScheduleNot applicable — the trigger is internalChannel cron
gRPCThe same oneChannel grpc

The measured unit is the delivery, not the request: one delivery leaves a receipt entry and exactly one verdict in the log. Which door it came through is read from a dedicated column, not from the kind of event.

One owner of execution

The execution core is synchronous, the edge is asynchronous, and there is a single owner of execution. When the installation is at capacity, the refusal is loud: the message stays durable, but no worker picks it up, and the log records a refusal kind distinct from a flow error. No kind of refusal enters the flows’ error rate.

Installation and configuration

An installation comes up knowing only the operations manual: publication, a request through a closed gate, an event in the log and in the UI, backup and restore, migrations over an older database.

Environment configuration is declared in the flow. A published flow that requires a key the installation does not supply stops start-up, naming the flow, the key and the variable — at start-up, not at the first message in production.

What this page does not cover

The limits are not a footnote to the capabilities. Each chapter below names its own, in its own section, so you can rule a case out in the first week.

The platform, chapter by chapter