Modules

Each module is its own Go module, so go get pulls in only what you use. The guide column is where you’ll find it in use; the API reference for each lives on pkg.go.dev.

Module	Does	Guide	API
auth	JWT, sessions, API keys, single-use tokens	Authenticate requests	ref
cache	Key-value caching, in-memory or Valkey	Cache expensive work	ref
config	Env, JSON, .env, AWS Secrets Manager	Configure an app	ref
database	database/sql and pgx pools, transactions	Connect a database	ref
email	Transactional email over AWS SES	Send email	ref
log	Structured logging, HTTP/OTLP shipping	Structured logging	ref
migrate	Service-owned migrations, rollback	Connect a database	ref
queue	Job queues backed by AWS SQS	Run background jobs	ref
storage	Object storage on S3 and compatible services	Store and serve files	ref
template	Template storage: memory, dir, FS, database	Serve HTML	ref
ui	HTML rendering, static files, HTMX fragments	Serve HTML	ref

How they fit together

No module imports another module’s service package. They meet through the provider interfaces declared in the core package, so any of them can be replaced by your own implementation or a test mock without the others noticing. The one shared dependency is gas/config: core and most modules embed its gasenv extension for environment detection and bind their settings through gas.ConfigProvider.

That is why every guide registers modules under an interface rather than a concrete type. See Services and DI.

What each constructor needs

A module’s New returns a constructor, not a service. The container calls it with the dependencies it declares, and every one of them must be registered or startup fails with no registration for <type>.

Constructor	Resolves from the container
cachemem.New(), cachevk.New()	gas.ConfigProvider, gas.Logger
database.New()	gas.ConfigProvider, gas.Logger
migrate.New()	gas.DatabaseProvider
s3.New()	gas.ConfigProvider, gas.Logger
sqs.New()	gas.ConfigProvider, gas.Logger
ses.New()	gas.TemplateProvider, gas.ConfigProvider, gas.Logger
jwt.New()	gas.ConfigProvider, gas.Logger
session.New(), apikey.New(), token.New()	gas.DatabaseProvider, gas.Logger, gas.MigrationManager, gas.ConfigProvider
ui.New[T]()	T (a gas.TemplateProvider), *gas.Router, gas.ConfigProvider, gas.Logger
templatedb.NewStore()	gas.DatabaseProvider, gas.Logger, gas.MigrationManager
templatedir.NewStore(path), templatefs.NewStore(fsys)	nothing; call the returned function yourself
gaslog.NewSlogLogger(), gaslog.NewZeroLogLogger()	nothing
config.New()	nothing; built before the app

Versioning

All modules share a single version and are released together. A release tags the root module vX.Y.Z and each submodule <dir>/vX.Y.Z, which is what go get github.com/gasmod/gas/auth@vX.Y.Z resolves against. Mixing versions across modules is not supported.

Gas is pre-1.0, so minor versions may contain breaking changes. See the changelog.