README
¶
fx/modules/bootstrap/function
fx module that runs a bootstrap/function handler through the adapter
commands provided in the boostrap.function.adapters group
(BSFunctionAdaptersGroupKey) — cloudevents HTTP, NATS, Pub/Sub, Kafka, AWS Lambda.
fxfact.NewApp(
fx.Provide(func() function.Handler[*event.Event] { return handle }),
cehttp.Module[*event.Event](),
functionfx.Module[*event.Event](middlewares),
).Run()
T must be *event.Event or []*event.Event.
Which adapter runs
Function.Run runs the adapter command the first CLI argument names
(app nats). With no command named, it runs the one
boost.bootstrap.function.default names, or the only adapter in the group:
an app that wires one adapter, as builder does, runs with no argument and no
key. No adapter, or more than one and none chosen, fails the boot with
NotValid (exit code 1) naming the adapters and the key, instead of
printing the usage.
Adapter clients
The nats, cloudevents_nats and Pub/Sub v2 adapter modules
(adapter/contrib/nats-io/nats.go/v1,
adapter/contrib/cloudevents/sdk-go/v2/contrib/nats-io/nats.go/v1,
adapter/contrib/cloud.google.com/pubsub/v2) come in two forms:
| Function | Client |
|---|---|
Module[T]() |
brings its own: the factory fx module of *nats.Conn or *pubsub.Client |
ModuleWithoutClient[T]() |
takes the one the app provides |
ModuleWithNamedClient[T](name) |
takes the one the app provides as name:"<name>" (nats, cenats, pubsub v2) |
Use ModuleWithoutClient when the app already provides that client, such as
the default client a publisher driver or an @Inject gets: fx accepts one
provider per type, so Module there fails the boot with "already provided".
builder generates it that way, and ModuleWithNamedClient for
@Function(client=x). All share one sync.Once: the first call wins.
The function runs the middlewares given to Module, then the
[]middleware.AnyErrorMiddleware[T] provided under the name
MiddlewaresName (bootstrap.function.middlewares), when there is one. That
is how a builder app passes the middlewares of its @Function:
fx.Provide(fx.Annotate(
func() []middleware.AnyErrorMiddleware[*event.Event] { return mws },
fx.ResultTags(`name:"`+functionfx.MiddlewaresName+`"`),
))
Lifecycle
- OnStart —
Function.Runruns in a goroutine, sofx.Newreturns andapp.Run()listens for SIGINT/SIGTERM. - OnStop — the context passed to
Run(and to the adapter command) is cancelled; the hook waits forRunto return, bounded by the stop context (fx's stop timeout), and returns the context error if it does not. - Run ends on its own (no stop requested) — the app is shut down with
exit code 0 on success, or 1 when
Runreturned an error (logged).
The nats, cloudevents_nats and gcp_pubsub (v1 and v2) adapters run on
that context (Helper.Run(cmd.Context())) and block until it is done: when
it is cancelled they take no new message, let the handler finish the one it
holds, with a context the stop does not cancel, and return, so SIGTERM stops
the app with exit code 0 well before the stop timeout. NATS drains its
subscriptions; Pub/Sub gives back a failed message instead of retrying it. A
NATS subject it cannot subscribe to, or a Pub/Sub subscription it cannot
receive on (pubsub: could not receive on <name>, e.g. one that does not
exist), fails Run, so the boot fails with exit code 1. Helper.Start() is
deprecated: it runs with a context that is never cancelled.
The Pub/Sub v1 adapter module provides the v1 *pubsub.Client
(fx/modules/factory/contrib/cloud.google.com/pubsub/v1.ClientModule())
whatever boost.factory.gcp.pubsub.version says, so
boost.bootstrap.function.adapter.pubsub.version=v1 alone turns it on.
Documentation
¶
Index ¶
Constants ¶
const ( BSFunctionAdaptersGroupKey = "boostrap.function.adapters" // MiddlewaresName names the optional []middleware.AnyErrorMiddleware[T] // the function runs after the middlewares given to Module, in order. // builder provides it for @Function(middlewares=[...]). MiddlewaresName = "bootstrap.function.middlewares" )
const (
Root = bootstrap.Root + ".function"
)
Variables ¶
This section is empty.
Functions ¶
func Module ¶
func Module[T any](m []middleware.AnyErrorMiddleware[T]) fx.Option
Module fx module for bootstrap function. The function runs from the app's OnStart and its context is cancelled on OnStop, so app.Run handles SIGTERM gracefully; when the function ends on its own the app shuts down, with exit code 1 if it failed. The function runs m, then the middlewares named MiddlewaresName when the app provides them.
Types ¶
This section is empty.
Source Files
Directories
¶
| Path | Synopsis |
|---|---|
|
contrib/cloud.google.com/pubsub
Package pubsub declares, once, the config the Pub/Sub v1 and v2 function adapter fx modules share: whether the adapter is on and which version it is.
|
Package pubsub declares, once, the config the Pub/Sub v1 and v2 function adapter fx modules share: whether the adapter is on and which version it is. |