github.com/demonoid81/containerd@v1.3.4/pkg/ttrpcutil/client.go (about)

     1  /*
     2     Copyright The containerd Authors.
     3  
     4     Licensed under the Apache License, Version 2.0 (the "License");
     5     you may not use this file except in compliance with the License.
     6     You may obtain a copy of the License at
     7  
     8         http://www.apache.org/licenses/LICENSE-2.0
     9  
    10     Unless required by applicable law or agreed to in writing, software
    11     distributed under the License is distributed on an "AS IS" BASIS,
    12     WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    13     See the License for the specific language governing permissions and
    14     limitations under the License.
    15  */
    16  
    17  package ttrpcutil
    18  
    19  import (
    20  	"sync"
    21  	"time"
    22  
    23  	v1 "github.com/containerd/containerd/api/services/ttrpc/events/v1"
    24  	"github.com/containerd/ttrpc"
    25  	"github.com/pkg/errors"
    26  )
    27  
    28  const ttrpcDialTimeout = 5 * time.Second
    29  
    30  type ttrpcConnector func() (*ttrpc.Client, error)
    31  
    32  // Client is the client to interact with TTRPC part of containerd server (plugins, events)
    33  type Client struct {
    34  	mu        sync.Mutex
    35  	connector ttrpcConnector
    36  	client    *ttrpc.Client
    37  	closed    bool
    38  }
    39  
    40  // NewClient returns a new containerd TTRPC client that is connected to the containerd instance provided by address
    41  func NewClient(address string, opts ...ttrpc.ClientOpts) (*Client, error) {
    42  	connector := func() (*ttrpc.Client, error) {
    43  		conn, err := ttrpcDial(address, ttrpcDialTimeout)
    44  		if err != nil {
    45  			return nil, errors.Wrap(err, "failed to connect")
    46  		}
    47  
    48  		client := ttrpc.NewClient(conn, opts...)
    49  		return client, nil
    50  	}
    51  
    52  	client, err := connector()
    53  	if err != nil {
    54  		return nil, err
    55  	}
    56  
    57  	return &Client{
    58  		connector: connector,
    59  		client:    client,
    60  	}, nil
    61  }
    62  
    63  // Reconnect re-establishes the TTRPC connection to the containerd daemon
    64  func (c *Client) Reconnect() error {
    65  	c.mu.Lock()
    66  	defer c.mu.Unlock()
    67  
    68  	if c.connector == nil {
    69  		return errors.New("unable to reconnect to containerd, no connector available")
    70  	}
    71  
    72  	if c.closed {
    73  		return errors.New("client is closed")
    74  	}
    75  
    76  	client, err := c.connector()
    77  	if err != nil {
    78  		return err
    79  	}
    80  
    81  	c.client = client
    82  	return nil
    83  }
    84  
    85  // EventsService creates an EventsService client
    86  func (c *Client) EventsService() v1.EventsService {
    87  	return v1.NewEventsClient(c.Client())
    88  }
    89  
    90  // Client returns the underlying TTRPC client object
    91  func (c *Client) Client() *ttrpc.Client {
    92  	c.mu.Lock()
    93  	defer c.mu.Unlock()
    94  
    95  	return c.client
    96  }
    97  
    98  // Close closes the clients TTRPC connection to containerd
    99  func (c *Client) Close() error {
   100  	c.mu.Lock()
   101  	defer c.mu.Unlock()
   102  
   103  	c.closed = true
   104  	return c.client.Close()
   105  }