Capabilities handling, database.

2019-09-09 21:52:32 +05:00
parent 4e614c094e
commit 28ddc32368
82 changed files with 12467 additions and 20 deletions
--- a/database/connection.go
+++ b/database/connection.go
@@ -0,0 +1,94 @@
+package database
+
+import (
+	// stdlib
+	"log"
+	"strings"
+	"time"
+
+	// local
+	"develop.pztrn.name/gonews/gonews/configuration"
+	"develop.pztrn.name/gonews/gonews/database/migrations"
+
+	// other
+	"github.com/jmoiron/sqlx"
+	// PostgreSQL driver.
+	_ "github.com/lib/pq"
+)
+
+func startConnectionWatcher() {
+	log.Println("Initializing database connection watcher...")
+
+	migrations.Initialize()
+
+	// Checking configuration validity.
+	// Parameters should not be specified in DSN.
+	if strings.Contains(configuration.Cfg.Database.DSN, "?") {
+		log.Fatalln("Database DSN should not contain parameters, specify them in DATABASE_PARAMS environment variable!")
+	}
+
+	// DSN should be defined.
+	if configuration.Cfg.Database.DSN == "" {
+		log.Fatalln("Database DSN should be defined!")
+	}
+
+	ticker := time.NewTicker(time.Second * time.Duration(configuration.Cfg.Database.Timeout))
+
+	// First start - manually.
+	_ = watcher()
+
+	// Then - every ticker tick.
+	for range ticker.C {
+		doBreak := watcher()
+		if doBreak {
+			break
+		}
+	}
+
+	ticker.Stop()
+	log.Println("Connection watcher stopped and connection to database was shutted down")
+	connWatcherStopped = true
+}
+
+// Actual connection watcher. Returns true if we should stop watching
+// (e.g. due to shutdown) and false if everything is okay.
+func watcher() bool {
+	// If we're shutting down - stop connection watcher.
+	if weAreShuttingDown {
+		log.Println("Closing database connection...")
+		err := Conn.Close()
+		if err != nil {
+			log.Println("Failed to close database connection")
+		}
+		Conn = nil
+		return true
+	}
+
+	// If connection is nil - try to establish (or reestablish)
+	// connection.
+	if Conn == nil {
+		log.Println("(Re)Establishing connection to PostgreSQL...")
+
+		// Compose DSN.
+		dsn := configuration.Cfg.Database.DSN
+		if configuration.Cfg.Database.Params != "" {
+			dsn += "?" + configuration.Cfg.Database.Params
+		}
+
+		// Connect to database.
+		dbConn, err := sqlx.Connect("postgres", dsn)
+		if err != nil {
+			log.Fatalf("Failed to connect to PostgreSQL database, will try to reconnect after %d seconds\n", configuration.Cfg.Database.Timeout)
+			return false
+		}
+
+		log.Println("Database connection (re)established")
+
+		// Migrate database.
+		migrations.Migrate(dbConn.DB)
+
+		Conn = dbConn
+	}
+
+	return false
+}
--- a/database/exported.go
+++ b/database/exported.go
@@ -0,0 +1,45 @@
+package database
+
+import (
+	// stdlib
+	"log"
+	"time"
+
+	// other
+	"github.com/jmoiron/sqlx"
+)
+
+var (
+	// Conn is database connection.
+	Conn *sqlx.DB
+
+	// Shutdown flags.
+	// Sets to true when Shutdown() is called to indicate other subsystes
+	// that we're shutting down.
+	weAreShuttingDown bool
+	// Sets to true when connection watcher will be stopped.
+	connWatcherStopped bool
+)
+
+func Initialize() {
+	log.Println("Initializing database handler...")
+
+	// Reset variables to their default startup state because they
+	// can be set to other values while executing tests.
+	Conn = nil
+	weAreShuttingDown = false
+	connWatcherStopped = false
+
+	go startConnectionWatcher()
+}
+
+func Shutdown() {
+	weAreShuttingDown = true
+	for {
+		if connWatcherStopped {
+			break
+		}
+	}
+
+	time.Sleep(time.Millisecond * 500)
+}
--- a/database/migrations/1_create_users_table.go
+++ b/database/migrations/1_create_users_table.go
@@ -0,0 +1,44 @@
+package migrations
+
+import (
+	// stdlib
+	"database/sql"
+)
+
+// CreateUsersTableUp creates local users table used for authentication.
+func CreateUsersTableUp(tx *sql.Tx) error {
+	if _, err := tx.Exec(`
+	CREATE TABLE users (
+		uuid			UUID NOT NULL,
+		login			TEXT NOT NULL,
+		password_hash	TEXT NOT NULL,
+		password_salt	TEXT NOT NULL,
+		active			BOOLEAN NOT NULL DEFAULT false,
+		created_at		TIMESTAMP WITH TIME ZONE NOT NULL
+	);
+
+	COMMENT ON COLUMN users.uuid IS 'User UUID';
+	COMMENT ON COLUMN users.login IS 'User login';
+	COMMENT ON COLUMN users.password_hash IS 'Hashed user password';
+	COMMENT ON COLUMN users.password_salt IS 'Salt for user password';
+	COMMENT ON COLUMN users.active IS 'Active user flag. 0 - banned';
+	COMMENT ON COLUMN users.created_at IS 'User registration timestamp';
+
+	CREATE INDEX users_uuid_idx ON users(uuid);
+	CREATE INDEX users_login_idx ON users(login);
+	CREATE INDEX users_created_at_idx ON users(created_at);
+	`); err != nil {
+		return err
+	}
+
+	return nil
+}
+
+// CreateUsersTableDown deletes local users table used for authentication.
+func CreateUsersTableDown(tx *sql.Tx) error {
+	if _, err := tx.Exec(`DROP TABLE users;`); err != nil {
+		return err
+	}
+
+	return nil
+}
--- a/database/migrations/exported.go
+++ b/database/migrations/exported.go
@@ -0,0 +1,81 @@
+package migrations
+
+import (
+	// stdlib
+	"database/sql"
+	"log"
+	"os"
+	"strconv"
+
+	// other
+	"github.com/pressly/goose"
+)
+
+func Initialize() {
+	log.Println("Initializing database migrations...")
+
+	_ = goose.SetDialect("postgres")
+
+	goose.AddNamedMigration("1_create_users_table.go", CreateUsersTableUp, CreateUsersTableDown)
+
+	// Migrations should be registered here.
+}
+
+func Migrate(db *sql.DB) {
+	log.Println("Starting database migration procedure...")
+
+	// Prepare migrations configuration.
+	var action = "UP"
+	actionFromEnv, actionFound := os.LookupEnv("DATABASE_ACTION")
+	if actionFound {
+		log.Println("Migration action override: " + actionFromEnv)
+		action = actionFromEnv
+	} else {
+		log.Println("Executing default migration action (UP)")
+	}
+
+	var count int64
+	countFromEnv, countFound := os.LookupEnv("DATABASE_COUNT")
+	if countFound {
+		log.Println("Migration count override: " + countFromEnv)
+		countAsInt, err := strconv.ParseInt(countFromEnv, 10, 64)
+		if err != nil {
+			log.Fatalln("Failed to convert count gathered from DATABASE_COUNT to integer")
+		}
+		count = countAsInt
+	} else {
+		log.Println("Applying or rollback this count of migrations: " + countFromEnv + ". 0 - all.")
+	}
+
+	// Execute migrations.
+	var err error
+	currentDBVersion, gooseerr := goose.GetDBVersion(db)
+	if gooseerr != nil {
+		log.Fatalln("Failed to get database version: " + gooseerr.Error())
+	}
+	log.Println("Current database version obtained: " + strconv.Itoa(int(currentDBVersion)))
+	if action == "UP" && count == 0 {
+		log.Println("Applying all unapplied migrations...")
+		err = goose.Up(db, ".")
+	} else if action == "UP" && count != 0 {
+		newVersion := currentDBVersion + count
+		log.Println("Migrating database to specific version: " + strconv.Itoa(int(newVersion)))
+		err = goose.UpTo(db, ".", newVersion)
+	} else if action == "DOWN" && count == 0 {
+		log.Println("Downgrading database to zero state, you'll need to re-apply migrations!")
+		err = goose.Down(db, ".")
+		log.Fatalln("Database downgraded to zero state. You have to re-apply migrations")
+	} else if action == "DOWN" && count != 0 {
+		newVersion := currentDBVersion - count
+		log.Println("Downgrading database to specific version: " + strconv.Itoa(int(newVersion)))
+		err = goose.DownTo(db, ".", newVersion)
+	} else {
+		log.Fatalln("Unsupported set of migration parameters, cannot continue: " + action + "/" + countFromEnv)
+	}
+
+	if err != nil {
+		log.Fatalln("Failed to execute migration sequence: " + err.Error())
+	}
+
+	log.Println("Database migrated successfully")
+}