Feature/service discovery

[Rekseto]

No description provided.

[Copilot]

Pull request overview

This PR introduces a service discovery system that enables nodes to advertise and discover services from other nodes in the network. The implementation includes a database-backed service registry, a pub/sub mechanism for broadcasting service changes, and shell operations for querying and synchronizing service information.

• Adds a new services module with discovery, persistence, and synchronization capabilities
• Implements a ServiceChangeFeed pub/sub mechanism for broadcasting service state changes
• Integrates the NAT module as an example service discoverer

Reviewed changes

Copilot reviewed 15 out of 15 changed files in this pull request and generated 4 comments.

Show a summary per file

File	Description
mod/services/module.go	Core interface defining the services module API and discovery options
mod/services/service.go	Service data structure representing a discoverable service
mod/services/service_change.go	Event type for service state changes (enabled/disabled)
mod/services/service_change_feed.go	Pub/sub broadcast primitive for service change events
mod/services/src/module.go	Main module implementation with remote service discovery logic
mod/services/src/op_discovery.go	Shell operation handler for discovering local services with snapshot and follow modes
mod/services/src/op_sync.go	Shell operation handler for synchronizing services from a remote identity
mod/services/src/loader.go	Module loader with database migration and dependency injection
mod/services/src/deps.go	Dependency injection setup that discovers ServiceDiscoverer implementations
mod/services/src/db.go	Database operations layer with transaction support
mod/services/src/db_service.go	Database model for cached service records
mod/nat/src/service_discoverer.go	NAT module's implementation of ServiceDiscoverer interface
mod/nat/src/module.go	Added service discovery fields to NAT module
mod/nat/src/loader.go	Initialize ServiceChangeFeed in NAT module loader
mod/all/mods.go	Register the new services module

Comments suppressed due to low confidence (1)

mod/nat/src/module.go:45

• The serviceChangeFeed is created in the loader but is never closed when the module shuts down. The Run method (line 41-45) doesn't call Close on the feed before returning. This could lead to resource leaks, particularly goroutines from Subscribe calls that may not properly clean up. Consider adding a defer statement to close the feed when the context is done.

func (mod *Module) Run(ctx *astral.Context) error {
	mod.ctx = ctx.IncludeZone(astral.ZoneNetwork)
	<-ctx.Done()

	return nil

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[Rekseto]

@cryptoarashi rebased on master to use new channel implementation

[cryptoarashi]

1. Ops should not contain heavy logic.

Move heavy logic to a module function DiscoverServices(...) (<-chan, error) and
use it in an op. See mod/objects the scope of OpSearch() vs Search(),
OpDescribe() vs Describe().

2. A single module should be able to expose more than one service. This implementation assumes all services will only post a single service in its snapshot collecting phase.

3. Object files are missing the init function adding them to the default blueprints.

[Rekseto]

1. Ops should not contain heavy logic.

Move heavy logic to a module function DiscoverServices(...) (<-chan, error) and use it in an op. See mod/objects the scope of OpSearch() vs Search(), OpDescribe() vs Describe().

2. A single module should be able to expose more than one service. This implementation assumes all services will only post a single service in its snapshot collecting phase.
3. Object files are missing the init function adding them to the default blueprints.

Done @cryptoarashi