ashiqyousuf/sbank

Purpose and process entry point

sbank is a Go banking-service backend: accounts, transfers, users, authentication sessions/tokens, and user lifecycle RPCs. main.go is the composition root, loading configuration and starting the service stack. The repository exposes both native gRPC and HTTP/JSON through a gRPC-Gateway-generated bridge; legacy/direct HTTP handlers also exist under api/.

API delivery surfaces

The primary contract is protobuf-defined user RPCs in proto/service_simple_bank.proto, with request/message definitions in proto/rpc_create_user.proto, proto/rpc_login_user.proto, and proto/rpc_update_user.proto. Generated server, gRPC, and gateway bindings reside in pb/service_simple_bank_grpc.pb.go and pb/service_simple_bank.pb.gw.go. OpenAPI/Swagger static assets are shipped in doc/swagger/, embedded through doc/statik/statik.go.

gRPC application layer

gapi/server.go implements the protobuf service and owns request handling. RPC implementations in gapi/rpc_create_user.go, gapi/rpc_login_user.go, and gapi/rpc_update_user.go convert protobuf inputs to persistence/auth operations and return API messages. gapi/authorization.go provides gRPC authorization interception, while gapi/error.go maps domain/storage failures to transport-level gRPC errors. This interceptor boundary does not automatically apply to gateway HTTP requests.

HTTP API layer

api/server.go provides an HTTP server/route layer alongside the gRPC-first API. Resource handlers are separated by banking concern: api/account.go, api/transfer.go, and api/user.go. api/middleware.go is the HTTP cross-cutting boundary for concerns such as authentication, distinct from gRPC interception. api/validator.go validates inbound HTTP payloads.

Persistence and transactional banking core

PostgreSQL schema evolution is defined in db/migration/000001_init_schema.up.sql, db/migration/000002_add_users.up.sql, and db/migration/000003_add_sessions.up.sql. SQL query specifications live in db/query/account.sql, db/query/transfer.sql, and db/query/session.sql; sqlc-generated typed access code is under db/sqlc/. db/sqlc/store.go is the principal persistence boundary, coordinating queries and likely transaction-scoped account/transfer/entry changes, preventing handlers from directly assembling banking transactions.

Identity, sessions, and credentials

User records and durable sessions are modeled via db/query/user.sql, db/query/session.sql, and generated types in db/sqlc/models.go. The token abstraction in token/maker.go allows authentication implementation substitution; token/jwt_maker.go and token/paseto_maker.go implement JWT and PASETO issuance/verification. Password hashing/verification belongs to util/password.go, keeping raw credentials out of transport and store layers.

Asynchronous verification capability

worker/distributor.go abstracts task publication, while worker/task_send_verify_email.go defines the email-verification task payload/work unit. This establishes an async boundary for external email delivery, although no concrete queue or mail-provider implementation appears in the tree.

Runtime and infrastructure

The runtime is Go (module metadata: go.mod) with PostgreSQL implied by SQL migrations and sqlc usage. Configuration is loaded through util/config.go with environment values represented by app.env. Protocol infrastructure includes gRPC, protobuf, gRPC-Gateway HTTP translation, and embedded Swagger UI/OpenAPI documentation.