process_group_handler.go

Documentation: github.com/chaos-mesh/chaos-mesh/pkg/chaosdaemon/tasks

     1  // Copyright 2021 Chaos Mesh Authors.
     2  //
     3  // Licensed under the Apache License, Version 2.0 (the "License");
     4  // you may not use this file except in compliance with the License.
     5  // You may obtain a copy of the License at
     6  //
     7  // http://www.apache.org/licenses/LICENSE-2.0
     8  //
     9  // Unless required by applicable law or agreed to in writing, software
    10  // distributed under the License is distributed on an "AS IS" BASIS,
    11  // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    12  // See the License for the specific language governing permissions and
    13  // limitations under the License.
    14  //
    15  
    16  package tasks
    17  
    18  import (
    19  	"strconv"
    20  
    21  	"github.com/go-logr/logr"
    22  
    23  	"github.com/chaos-mesh/chaos-mesh/pkg/cerr"
    24  	"github.com/chaos-mesh/chaos-mesh/pkg/chaosdaemon/util"
    25  )
    26  
    27  var ErrNotTypeSysID = cerr.NotType[SysPID]()
    28  var ErrNotFoundSysID = cerr.NotFoundType[SysPID]()
    29  
    30  type SysPID uint32
    31  
    32  func (s SysPID) ToID() string {
    33  	return strconv.FormatUint(uint64(s), 10)
    34  }
    35  
    36  // ChaosOnProcessGroup is used for inject a chaos on a linux process group.
    37  // Fork is used for create a new chaos on child process.
    38  // Assign is used for update a chaos on child process.
    39  type ChaosOnProcessGroup interface {
    40  	Fork() (ChaosOnProcessGroup, error)
    41  	Assign
    42  
    43  	Injectable
    44  	Recoverable
    45  }
    46  
    47  // ProcessGroupHandler implements injecting & recovering on a linux process group.
    48  type ProcessGroupHandler struct {
    49  	LeaderProcess ChaosOnProcessGroup
    50  	childMap      map[IsID]ChaosOnProcessGroup
    51  	Logger        logr.Logger
    52  }
    53  
    54  func NewProcessGroupHandler(logger logr.Logger, leader ChaosOnProcessGroup) ProcessGroupHandler {
    55  	return ProcessGroupHandler{
    56  		LeaderProcess: leader,
    57  		childMap:      make(map[IsID]ChaosOnProcessGroup),
    58  		Logger:        logr.New(logger.GetSink()),
    59  	}
    60  }
    61  
    62  // Inject try to inject the leader process and then try to inject child process.
    63  // If something wrong in injecting a child process, Inject will just log error & continue.
    64  func (gp *ProcessGroupHandler) Inject(pid IsID) error {
    65  	sysPID, ok := pid.(SysPID)
    66  	if !ok {
    67  		return ErrNotTypeSysID.WrapInput(pid).Err()
    68  	}
    69  
    70  	err := gp.LeaderProcess.Inject(sysPID)
    71  	if err != nil {
    72  		return cerr.FromErr(err).Wrapf("inject leader process: %v", sysPID).Err()
    73  	}
    74  
    75  	childPIDs, err := util.GetChildProcesses(uint32(sysPID), gp.Logger)
    76  	if err != nil {
    77  		return cerr.NotFound("child process").WrapErr(err).Err()
    78  	}
    79  
    80  	for _, childPID := range childPIDs {
    81  		childSysPID := SysPID(childPID)
    82  		if childProcessChaos, ok := gp.childMap[childSysPID]; ok {
    83  			err := gp.LeaderProcess.Assign(childProcessChaos)
    84  			if err != nil {
    85  				gp.Logger.Error(err, "failed to assign old child process")
    86  				continue
    87  			}
    88  			err = childProcessChaos.Inject(childSysPID)
    89  			if err != nil {
    90  				gp.Logger.Error(err, "failed to inject old child process")
    91  			}
    92  		} else {
    93  			childProcessChaos, err := gp.LeaderProcess.Fork()
    94  			if err != nil {
    95  				gp.Logger.Error(err, "failed to create child process")
    96  				continue
    97  			}
    98  			err = childProcessChaos.Inject(childSysPID)
    99  			if err != nil {
   100  				gp.Logger.Error(err, "failed to inject new child process")
   101  				continue
   102  			}
   103  			gp.childMap[childSysPID] = childProcessChaos
   104  		}
   105  	}
   106  	return nil
   107  }
   108  
   109  // Recover try to recover the leader process and then try to recover child process.
   110  func (gp *ProcessGroupHandler) Recover(pid IsID) error {
   111  	_, ok := pid.(SysPID)
   112  	if !ok {
   113  		return ErrNotTypeSysID.WrapInput(pid).Err()
   114  	}
   115  	err := gp.LeaderProcess.Recover(pid)
   116  	if err != nil {
   117  		return cerr.FromErr(err).Wrapf("recovery leader process : %v", pid).Err()
   118  	}
   119  
   120  	for childID, group := range gp.childMap {
   121  		childSysPID, ok := childID.(SysPID)
   122  		if !ok {
   123  			gp.Logger.Error(cerr.NotType[SysPID]().WrapInput(childID).Err(),
   124  				"failed to recover old child process")
   125  		}
   126  
   127  		err := group.Recover(childSysPID)
   128  		if err != nil {
   129  			gp.Logger.Error(err, "failed to recover old child process")
   130  		}
   131  	}
   132  	return nil
   133  }
   134