db: reconnect on connection errors

config.go

@@ -28,6 +28,11 @@ import (
 
 // Settings defines methods to get or set configuration values.
 type Settings interface {
+	// SetRetryQueryOnError enables or disable query retry-on-error features.
+	SetRetryQueryOnError(bool)
+	// Returns true if query retry is enabled.
+	RetryQueryOnError() bool
+
 	// SetLogging enables or disables logging.
 	SetLogging(bool)
 	// LoggingEnabled returns true if logging is enabled, false otherwise.
@@ -45,6 +50,8 @@ type conf struct {
 	queryLogger   Logger
 	queryLoggerMu sync.RWMutex
 	defaultLogger defaultLogger
+
+	queryRetryOnError uint32
 }
 
 func (c *conf) Logger() Logger {
@@ -58,27 +65,43 @@ func (c *conf) Logger() Logger {
 	return c.queryLogger
 }
 
+func (c *conf) SetRetryQueryOnError(v bool) {
+	c.setBinaryOption(&c.queryRetryOnError, v)
+}
+
+func (c *conf) RetryQueryOnError() bool {
+	return c.binaryOption(&c.queryRetryOnError)
+}
+
 func (c *conf) SetLogger(lg Logger) {
 	c.queryLoggerMu.Lock()
 	defer c.queryLoggerMu.Unlock()
 
 	c.queryLogger = lg
 }
 
-func (c *conf) SetLogging(value bool) {
+func (c *conf) binaryOption(dest *uint32) bool {
+	if v := atomic.LoadUint32(dest); v == 1 {
+		return true
+	}
+	return false
+}
+
+func (c *conf) setBinaryOption(dest *uint32, value bool) {
 	if value {
-		atomic.StoreUint32(&c.loggingEnabled, 1)
+		atomic.StoreUint32(dest, 1)
 		return
 	}
-	atomic.StoreUint32(&c.loggingEnabled, 0)
+	atomic.StoreUint32(dest, 0)
+}
+
+func (c *conf) SetLogging(value bool) {
+	c.setBinaryOption(&c.loggingEnabled, value)
 }
 
 func (c *conf) LoggingEnabled() bool {
-	if v := atomic.LoadUint32(&c.loggingEnabled); v == 1 {
-		return true
-	}
-	return false
+	return c.binaryOption(&c.loggingEnabled)
 }
 
-// Conf provides global configuration settings for upper-db.
+// Conf provides default global configuration settings for upper-db.
 var Conf Settings = &conf{}

db.go

@@ -268,6 +268,15 @@ func newCompound(c ...Compound) *compound {
 	return &compound{c}
 }
 
+func defaultJoin(in ...Compound) []Compound {
+	for i := range in {
+		if cond, ok := in[i].(Cond); ok && len(cond) > 1 {
+			in[i] = And(cond)
+		}
+	}
+	return in
+}
+
 func (c *compound) Sentences() []Compound {
 	return c.conds
 }
@@ -292,7 +301,7 @@ type Union struct {
 
 // Or adds more terms to the compound.
 func (o *Union) Or(conds ...Compound) *Union {
-	o.compound.push(conds...)
+	o.compound.push(defaultJoin(conds...)...)
 	return o
 }
 
@@ -420,7 +429,7 @@ func And(conds ...Compound) *Intersection {
 //		db.Cond{"year": 1987},
 //	)
 func Or(conds ...Compound) *Union {
-	return &Union{compound: newCompound(conds...)}
+	return &Union{compound: newCompound(defaultJoin(conds...)...)}
 }
 
 // Raw marks chunks of data as protected, so they pass directly to the query

errors.go

@@ -27,26 +27,28 @@ import (
 
 // Error messages.
 var (
-	ErrNoMoreRows               = errors.New(`upper: no more rows in this result set`)
-	ErrNotConnected             = errors.New(`upper: you're currently not connected`)
-	ErrMissingDatabaseName      = errors.New(`upper: missing database name`)
-	ErrMissingCollectionName    = errors.New(`upper: missing collection name`)
-	ErrCollectionDoesNotExist   = errors.New(`upper: collection does not exist`)
-	ErrSockerOrHost             = errors.New(`upper: you may connect either to a unix socket or a tcp address, but not both`)
-	ErrQueryLimitParam          = errors.New(`upper: a query can accept only one limit parameter`)
-	ErrQuerySortParam           = errors.New(`upper: a query can accept only one order by parameter`)
-	ErrQueryOffsetParam         = errors.New(`upper: a query can accept only one offset parameter`)
-	ErrMissingConditions        = errors.New(`upper: missing selector conditions`)
-	ErrUnsupported              = errors.New(`upper: this action is currently unsupported on this database`)
-	ErrUndefined                = errors.New(`upper: this value is undefined`)
-	ErrQueryIsPending           = errors.New(`upper: can't execute this instruction while the result set is still open`)
-	ErrUnsupportedDestination   = errors.New(`upper: unsupported destination type`)
-	ErrUnsupportedType          = errors.New(`upper: this type does not support marshaling`)
-	ErrUnsupportedValue         = errors.New(`upper: this value does not support unmarshaling`)
-	ErrUnknownConditionType     = errors.New(`upper: arguments of type %T can't be used as constraints`)
-	ErrTooManyClients           = errors.New(`upper: can't connect to database server: too many clients`)
-	ErrGivingUpTryingToConnect  = errors.New(`upper: giving up trying to connect: too many clients`)
-	ErrMissingConnURL           = errors.New(`upper: missing DSN`)
-	ErrNotImplemented           = errors.New(`upper: call not implemented`)
-	ErrAlreadyWithinTransaction = errors.New(`upper: already within a transaction`)
+	ErrNoMoreRows                  = errors.New(`upper: no more rows in this result set`)
+	ErrNotConnected                = errors.New(`upper: you're currently not connected`)
+	ErrMissingDatabaseName         = errors.New(`upper: missing database name`)
+	ErrMissingCollectionName       = errors.New(`upper: missing collection name`)
+	ErrCollectionDoesNotExist      = errors.New(`upper: collection does not exist`)
+	ErrSockerOrHost                = errors.New(`upper: you may connect either to a unix socket or a tcp address, but not both`)
+	ErrQueryLimitParam             = errors.New(`upper: a query can accept only one limit parameter`)
+	ErrQuerySortParam              = errors.New(`upper: a query can accept only one order by parameter`)
+	ErrQueryOffsetParam            = errors.New(`upper: a query can accept only one offset parameter`)
+	ErrMissingConditions           = errors.New(`upper: missing selector conditions`)
+	ErrUnsupported                 = errors.New(`upper: this action is currently unsupported on this database`)
+	ErrUndefined                   = errors.New(`upper: this value is undefined`)
+	ErrQueryIsPending              = errors.New(`upper: can't execute this instruction while the result set is still open`)
+	ErrUnsupportedDestination      = errors.New(`upper: unsupported destination type`)
+	ErrUnsupportedType             = errors.New(`upper: this type does not support marshaling`)
+	ErrUnsupportedValue            = errors.New(`upper: this value does not support unmarshaling`)
+	ErrUnknownConditionType        = errors.New(`upper: arguments of type %T can't be used as constraints`)
+	ErrTooManyClients              = errors.New(`upper: can't connect to database server: too many clients`)
+	ErrGivingUpTryingToConnect     = errors.New(`upper: giving up trying to connect: too many clients`)
+	ErrTooManyReconnectionAttempts = errors.New(`upper: too many reconnection attempts`)
+	ErrMissingConnURL              = errors.New(`upper: missing DSN`)
+	ErrNotImplemented              = errors.New(`upper: call not implemented`)
+	ErrAlreadyWithinTransaction    = errors.New(`upper: already within a transaction`)
+	ErrServerRefusedConnection     = errors.New(`upper: database server refused connection`)
 )