.

go/xcommon/xnet/lonet/lonet.go

@@ -22,7 +22,7 @@
 // Package lonet provides TCP network simulated on top of localhost TCP loopback.
 //
 // For testing distributed systems it is sometimes handy to imitate network of
-// several TCP hosts. It is also handy that port allocated on Dial/Listen/Accept on
+// several TCP hosts. It is also handy that ports allocated on Dial/Listen/Accept on
 // that hosts be predictable - that would help tests to verify network events
 // against expected sequence. When whole system could be imitated in 1 OS-level
 // process, package lab.nexedi.com/kirr/go123/xnet/pipenet serves the task via
@@ -32,7 +32,7 @@
 //
 // Similarly to pipenet addresses on lonet are host:port pairs and several
 // hosts could be created with different names. A host is xnet.Networker and
-// so can be worked with similarly to regular TCP network with
+// so can be worked with similarly to regular TCP network access-point with
 // Dial/Listen/Accept.  Host's ports allocation is predictable: ports of a host
 // are contiguous integer sequence starting from 1 that are all initially free,
 // and whenever autobind is requested the first free port of the host will be

go/xcommon/xnet/lonet/registry_sqlite.go

@@ -23,9 +23,12 @@ package lonet
 import (
 	"context"
 	"errors"
+	"fmt"
 
 	"crawshaw.io/sqlite"
 	"crawshaw.io/sqlite/sqliteutil"
+
+	"lab.nexedi.com/kirr/go123/xerr"
 )
 
 // registry schema
@@ -41,6 +44,8 @@ import (
 // "schemaver"	str(int) - version of schema.
 // "network"    text     - name of lonet network this registry serves.
 
+const schemaVer = "lonet.1"
+
 type sqliteRegistry struct {
 	dbpool *sqlite.Pool
 
@@ -48,8 +53,9 @@ type sqliteRegistry struct {
 }
 
 // openRegistrySqlite opens SQLite registry located at dburi.
-// XXX network name?
-func openRegistrySQLite(ctx context.Context, dburi string) (_ *sqliteRegistry, err error) {
+//
+// the registry is setup/verified to be serving specified lonet network.
+func openRegistrySQLite(ctx context.Context, dburi, network string) (_ *sqliteRegistry, err error) {
 	r := &sqliteRegistry{uri: dburi}
 	defer r.regerr(&err, "open")
 
@@ -60,7 +66,7 @@ func openRegistrySQLite(ctx context.Context, dburi string) (_ *sqliteRegistry, e
 
 	r.dbpool = dbpool
 
-	err = r.setup(ctx)
+	err = r.setup(ctx, network)
 	if err != nil {
 		r.Close()
 		return nil, err
@@ -90,8 +96,8 @@ func (r *sqliteRegistry) withConn(ctx context.Context, f func(*sqlite.Conn) erro
 	return f(conn)
 }
 
-var errNoRows   = errors.New("query1: empty result")
-var errManyRows = errors.New("query1: multiple results")
+var errNoRows   = errors.New("query: empty result")
+var errManyRows = errors.New("query: multiple results")
 
 // query1 is like sqliteutil.Exec but checks that exactly 1 row is returned.
 //
@@ -116,9 +122,9 @@ func query1(conn *sqlite.Conn, query string, resultf func(stmt *sqlite.Stmt), ar
 	return nil
 }
 
-func (r *sqliteRegistry) setup(ctx context.Context) (err error) {
-	return r.withConn(ctx, func(conn *sqlite.Conn) error {
-		err := sqliteutil.ExecScript(conn, `
+func (r *sqliteRegistry) setup(ctx context.Context, network string) error {
+	return r.withConn(ctx, func(conn *sqlite.Conn) (err error) {
+		err = sqliteutil.ExecScript(conn, `
 			CREATE TABLE IF NOT EXISTS hosts (
 				hostname	TEXT NON NULL PRIMARY KEY,
 				osladdr		TEXT NON NULL
@@ -133,13 +139,79 @@ func (r *sqliteRegistry) setup(ctx context.Context) (err error) {
 			return err
 		}
 
-		// XXX check schemaver
-		// XXX check network name
+		// do check/init under transaction
+		defer sqliteutil.Save(conn)(&err)
+
+		// XXX vvv review error handling
+
+		// check/init schema version
+		ver, err := r.config(conn, "schemaver")
+		if err != nil {
+			return err
+		}
+		if ver == "" {
+			ver = schemaVer
+			err = r.setConfig(conn, "schemaver", ver)
+			if err != nil {
+				return err
+			}
+		}
+		if ver != schemaVer {
+			return fmt.Errorf("schema version mismatch: want %q; have %q", schemaVer, ver)
+		}
+
+		// check/init network name
+		dbnetwork, err := r.config(conn, "network")
+		if err != nil {
+			return err
+		}
+		if dbnetwork == "" {
+			dbnetwork = network
+			err = r.setConfig(conn, "network", dbnetwork)
+			if err != nil {
+				return err
+			}
+		}
+		if dbnetwork != network {
+			return fmt.Errorf("network name mismatch: want %q; have %q", network, dbnetwork)
+		}
+
 
 		return nil
 	})
 }
 
+// config gets one registry configuration value by name.
+//
+// if there is no record corresponding to name ("", nil) is returned.
+// XXX add ok ret to indicate presence of value?
+func (r *sqliteRegistry) config(conn *sqlite.Conn, name string) (value string, err error) {
+	defer xerr.Contextf(&err, "config: get %q", name)
+
+	err = query1(conn, "SELECT value FROM meta WHERE name = ?", func(stmt *sqlite.Stmt) {
+		value = stmt.ColumnText(0)
+	}, name)
+
+	switch err {
+	case errNoRows:
+		return "", nil
+	case errManyRows:
+		value = ""
+	}
+
+	return value, err
+}
+
+// setConfig sets one registry configuration value by name.
+func (r *sqliteRegistry) setConfig(conn *sqlite.Conn, name, value string) (err error) {
+	defer xerr.Contextf(&err, "config: set %q = %q", name, value)
+
+	err = sqliteutil.Exec(conn,
+		"INSERT OR REPLACE INTO meta (name, value) VALUES (?, ?)", nil,
+		name, value)
+	return err
+}
+
 func (r *sqliteRegistry) Announce(ctx context.Context, hostname, osladdr string) (err error) {
 	defer r.regerr(&err, "announce", hostname, osladdr)
 
@@ -149,7 +221,7 @@ func (r *sqliteRegistry) Announce(ctx context.Context, hostname, osladdr string)
 			hostname, osladdr)
 
 		switch sqlite.ErrCode(err) {
-		case sqlite.SQLITE_CONSTRAINT_UNIQUE:	// XXX test
+		case sqlite.SQLITE_CONSTRAINT_UNIQUE:
 			err = errHostDup
 		}
 

go/xcommon/xnet/lonet/registry_sqlite_test.go

@@ -21,6 +21,7 @@ package lonet
 
 import (
 	"context"
+	"fmt"
 	"io/ioutil"
 	"os"
 	"testing"
@@ -39,7 +40,7 @@ func TestRegistrySQLite(t *testing.T) {
 
 	ctx := context.Background()
 
-	r, err := openRegistrySQLite(ctx, dbpath)
+	r, err := openRegistrySQLite(ctx, dbpath, "aaa")
 	X(err)
 
 	// query checks that result of Query(hostname) is as expected.
@@ -112,7 +113,7 @@ func TestRegistrySQLite(t *testing.T) {
 	query(r, "α", "alpha:1234")
 	query(r, "β", ø)
 
-	r2, err := openRegistrySQLite(ctx, dbpath)
+	r2, err := openRegistrySQLite(ctx, dbpath, "aaa")
 	// r2.Network() == ...
 	query(r2, "α", "alpha:1234")
 	query(r2, "β", ø)
@@ -133,4 +134,15 @@ func TestRegistrySQLite(t *testing.T) {
 	X(r2.Close())
 
 	query(r2, "α", errRegistryDown)
+
+
+	// verify network mismatch detection works
+	r3, err := openRegistrySQLite(ctx, dbpath, "bbb")
+	if !(r3 == nil && err != nil) {
+		t.Fatalf("network mismatch: not detected")
+	}
+	errWant := fmt.Sprintf(`%s: open []: network name mismatch: want "bbb"; have "aaa"`, dbpath)
+	if err.Error() != errWant {
+		t.Fatalf("network mismatch: error:\nhave: %q\nwant: %q", err.Error(), errWant)
+	}
 }