github.com/jefferai/terraform@v0.3.7-0.20150310153852-f7512ca29fcf/command/output.go (about)

     1  package command
     2  
     3  import (
     4  	"flag"
     5  	"fmt"
     6  	"strings"
     7  )
     8  
     9  // OutputCommand is a Command implementation that reads an output
    10  // from a Terraform state and prints it.
    11  type OutputCommand struct {
    12  	Meta
    13  }
    14  
    15  func (c *OutputCommand) Run(args []string) int {
    16  	args = c.Meta.process(args, false)
    17  
    18  	cmdFlags := flag.NewFlagSet("output", flag.ContinueOnError)
    19  	cmdFlags.StringVar(&c.Meta.statePath, "state", DefaultStateFilename, "path")
    20  	cmdFlags.Usage = func() { c.Ui.Error(c.Help()) }
    21  	if err := cmdFlags.Parse(args); err != nil {
    22  		return 1
    23  	}
    24  
    25  	args = cmdFlags.Args()
    26  	if len(args) != 1 || args[0] == "" {
    27  		c.Ui.Error(
    28  			"The output command expects exactly one argument with the name\n" +
    29  				"of an output variable.\n")
    30  		cmdFlags.Usage()
    31  		return 1
    32  	}
    33  	name := args[0]
    34  
    35  	stateStore, err := c.Meta.State()
    36  	if err != nil {
    37  		c.Ui.Error(fmt.Sprintf("Error reading state: %s", err))
    38  		return 1
    39  	}
    40  
    41  	state := stateStore.State()
    42  	if len(state.RootModule().Outputs) == 0 {
    43  		c.Ui.Error(fmt.Sprintf(
    44  			"The state file has no outputs defined. Define an output\n" +
    45  				"in your configuration with the `output` directive and re-run\n" +
    46  				"`terraform apply` for it to become available."))
    47  		return 1
    48  	}
    49  	v, ok := state.RootModule().Outputs[name]
    50  	if !ok {
    51  		c.Ui.Error(fmt.Sprintf(
    52  			"The output variable requested could not be found in the state\n" +
    53  				"file. If you recently added this to your configuration, be\n" +
    54  				"sure to run `terraform apply`, since the state won't be updated\n" +
    55  				"with new output variables until that command is run."))
    56  		return 1
    57  	}
    58  
    59  	c.Ui.Output(v)
    60  	return 0
    61  }
    62  
    63  func (c *OutputCommand) Help() string {
    64  	helpText := `
    65  Usage: terraform output [options] NAME
    66  
    67    Reads an output variable from a Terraform state file and prints
    68    the value.
    69  
    70  Options:
    71  
    72    -state=path      Path to the state file to read. Defaults to
    73                     "terraform.tfstate".
    74  
    75  `
    76  	return strings.TrimSpace(helpText)
    77  }
    78  
    79  func (c *OutputCommand) Synopsis() string {
    80  	return "Read an output from a state file"
    81  }