github.com/1aal/kubeblocks@v0.0.0-20231107070852-e1c03e598921/pkg/controller/graph/transformer.go (about)

     1  /*
     2  Copyright (C) 2022-2023 ApeCloud Co., Ltd
     3  
     4  This file is part of KubeBlocks project
     5  
     6  This program is free software: you can redistribute it and/or modify
     7  it under the terms of the GNU Affero General Public License as published by
     8  the Free Software Foundation, either version 3 of the License, or
     9  (at your option) any later version.
    10  
    11  This program is distributed in the hope that it will be useful
    12  but WITHOUT ANY WARRANTY; without even the implied warranty of
    13  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    14  GNU Affero General Public License for more details.
    15  
    16  You should have received a copy of the GNU Affero General Public License
    17  along with this program.  If not, see <http://www.gnu.org/licenses/>.
    18  */
    19  
    20  package graph
    21  
    22  import (
    23  	"context"
    24  	"errors"
    25  
    26  	"github.com/go-logr/logr"
    27  	"k8s.io/client-go/tools/record"
    28  
    29  	"github.com/1aal/kubeblocks/pkg/controller/client"
    30  	intctrlutil "github.com/1aal/kubeblocks/pkg/controllerutil"
    31  )
    32  
    33  // TransformContext is used by Transformer.Transform
    34  type TransformContext interface {
    35  	GetContext() context.Context
    36  	GetClient() client.ReadonlyClient
    37  	GetRecorder() record.EventRecorder
    38  	GetLogger() logr.Logger
    39  }
    40  
    41  // Transformer transforms a DAG to a new version
    42  type Transformer interface {
    43  	Transform(ctx TransformContext, dag *DAG) error
    44  }
    45  
    46  // TransformerChain chains a group Transformer together
    47  type TransformerChain []Transformer
    48  
    49  // ErrPrematureStop is used to stop the Transformer chain for some purpose.
    50  // Use it in Transformer.Transform when all jobs have done and no need to run following transformers
    51  var ErrPrematureStop = errors.New("Premature-Stop")
    52  
    53  // ApplyTo applies TransformerChain t to dag
    54  func (r TransformerChain) ApplyTo(ctx TransformContext, dag *DAG) error {
    55  	var delayedError error
    56  	for _, transformer := range r {
    57  		if err := transformer.Transform(ctx, dag); err != nil {
    58  			if intctrlutil.IsDelayedRequeueError(err) {
    59  				if delayedError == nil {
    60  					delayedError = err
    61  				}
    62  				continue
    63  			}
    64  			return ignoredIfPrematureStop(err)
    65  		}
    66  	}
    67  	return delayedError
    68  }
    69  
    70  func ignoredIfPrematureStop(err error) error {
    71  	if err == ErrPrematureStop {
    72  		return nil
    73  	}
    74  	return err
    75  }