gvisor.dev/gvisor@v0.0.0-20240520182842-f9d4d51c7e0f/runsc/cmd/state.go (about)

     1  // Copyright 2018 The gVisor 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  package cmd
    16  
    17  import (
    18  	"context"
    19  	"encoding/json"
    20  	"os"
    21  
    22  	"github.com/google/subcommands"
    23  	"gvisor.dev/gvisor/pkg/log"
    24  	"gvisor.dev/gvisor/runsc/cmd/util"
    25  	"gvisor.dev/gvisor/runsc/config"
    26  	"gvisor.dev/gvisor/runsc/container"
    27  	"gvisor.dev/gvisor/runsc/flag"
    28  )
    29  
    30  // State implements subcommands.Command for the "state" command.
    31  type State struct{}
    32  
    33  // Name implements subcommands.Command.Name.
    34  func (*State) Name() string {
    35  	return "state"
    36  }
    37  
    38  // Synopsis implements subcommands.Command.Synopsis.
    39  func (*State) Synopsis() string {
    40  	return "get the state of a container"
    41  }
    42  
    43  // Usage implements subcommands.Command.Usage.
    44  func (*State) Usage() string {
    45  	return `state [flags] <container id> - get the state of a container`
    46  }
    47  
    48  // SetFlags implements subcommands.Command.SetFlags.
    49  func (*State) SetFlags(*flag.FlagSet) {}
    50  
    51  // Execute implements subcommands.Command.Execute.
    52  func (*State) Execute(_ context.Context, f *flag.FlagSet, args ...any) subcommands.ExitStatus {
    53  	if f.NArg() != 1 {
    54  		f.Usage()
    55  		return subcommands.ExitUsageError
    56  	}
    57  
    58  	id := f.Arg(0)
    59  	conf := args[0].(*config.Config)
    60  
    61  	c, err := container.Load(conf.RootDir, container.FullID{ContainerID: id}, container.LoadOpts{})
    62  	if err != nil {
    63  		util.Fatalf("loading container: %v", err)
    64  	}
    65  
    66  	state := c.State()
    67  	log.Debugf("Returning state for container %q: %+v", c.ID, state)
    68  
    69  	// Write json-encoded state directly to stdout.
    70  	encoder := json.NewEncoder(os.Stdout)
    71  	encoder.SetIndent("", "  ")
    72  	if err := encoder.Encode(state); err != nil {
    73  		util.Fatalf("error marshaling container state: %v", err)
    74  	}
    75  	return subcommands.ExitSuccess
    76  }