FEAT: Init Discovery Service

discovery/internal/db/client.go

@@ -0,0 +1,30 @@
+package db
+
+import (
+	"context"
+	"database/sql"
+	"fmt"
+	"log"
+)
+
+func CreateDBConnection(connectionString string) *sql.DB {
+	sqlDB, err := sql.Open("postgres", connectionString)
+	if err != nil {
+		panic(fmt.Errorf("db: cannot open connection: %w", err))
+	}
+
+	return sqlDB
+}
+
+func CloseConnection(SQLDB *sql.DB) {
+	err := SQLDB.Close()
+	if err != nil {
+		log.Fatalf("Error Closing DB Connection: %s", err)
+	}
+}
+
+func AssertSuccessfulConnection(ctx context.Context, SQLDB *sql.DB) {
+	if err := SQLDB.PingContext(ctx); err != nil {
+		panic(fmt.Errorf("db: cannot connect: %w", err))
+	}
+}

discovery/internal/db/migrate.go

@@ -0,0 +1,38 @@
+package db
+
+import (
+	"database/sql"
+	"embed"
+	"errors"
+	"fmt"
+
+	"github.com/golang-migrate/migrate/v4"
+	"github.com/golang-migrate/migrate/v4/database/postgres"
+	"github.com/golang-migrate/migrate/v4/source/iofs"
+)
+
+//go:embed migrations/*.sql
+var migrationsFS embed.FS
+
+func Migrate(sqlDB *sql.DB) error {
+	driver, err := postgres.WithInstance(sqlDB, &postgres.Config{})
+	if err != nil {
+		return fmt.Errorf("db: creating migration driver: %w", err)
+	}
+
+	source, err := iofs.New(migrationsFS, "migrations")
+	if err != nil {
+		return fmt.Errorf("db: loading embedded migrations: %w", err)
+	}
+
+	m, err := migrate.NewWithInstance("iofs", source, "postgres", driver)
+	if err != nil {
+		return fmt.Errorf("db: initializing migrator: %w", err)
+	}
+
+	if err := m.Up(); err != nil && !errors.Is(err, migrate.ErrNoChange) {
+		return fmt.Errorf("db: applying migrations: %w", err)
+	}
+
+	return nil
+}

discovery/internal/db/migrations/0001_init.down.sql

@@ -0,0 +1,2 @@
+-- Nothing to undo: 0001 creates no objects.
+SELECT 1;

discovery/internal/db/migrations/0001_init.up.sql

@@ -0,0 +1,6 @@
+-- Discovery's schema starts here. The service owns its own database — the
+-- `discovery` role and same-named database provisioned by newServiceDatabase
+-- in infrastructure/main.go — and shares no tables with cms, so nothing is
+-- created yet. The file exists because internal/db/migrate.go embeds
+-- migrations/*.sql: with no migration at all the package would not compile.
+SELECT 1;

discovery/internal/db/repositories/repositories.go

@@ -0,0 +1,7 @@
+// Package repositories holds every SQL statement the service runs. A
+// repository is a struct carrying the *sql.DB opened by db.CreateDBConnection
+// and is assigned to a package-level var in main, the way cms wires VideoRepo
+// and CatagoriesRepo, so handlers call through something substitutable.
+//
+// Empty until discovery has tables to read.
+package repositories