open-nomad/command/node_drain.go
2016-03-24 14:43:20 -07:00

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package command
import (
"fmt"
"strings"
)
type NodeDrainCommand struct {
Meta
}
func (c *NodeDrainCommand) Help() string {
helpText := `
Usage: nomad node-drain [options] <node>
Toggles node draining on a specified node. It is required
that either -enable or -disable is specified, but not both.
General Options:
` + generalOptionsUsage() + `
Node Drain Options:
-disable
Disable draining for the specified node.
-enable
Enable draining for the specified node.
-yes
Automatic yes to prompts.
`
return strings.TrimSpace(helpText)
}
func (c *NodeDrainCommand) Synopsis() string {
return "Toggle drain mode on a given node"
}
func (c *NodeDrainCommand) Run(args []string) int {
var enable, disable, autoYes bool
flags := c.Meta.FlagSet("node-drain", FlagSetClient)
flags.Usage = func() { c.Ui.Output(c.Help()) }
flags.BoolVar(&enable, "enable", false, "Enable drain mode")
flags.BoolVar(&disable, "disable", false, "Disable drain mode")
flags.BoolVar(&autoYes, "yes", false, "Automatic yes to prompts.")
if err := flags.Parse(args); err != nil {
return 1
}
// Check that we got either enable or disable, but not both.
if (enable && disable) || (!enable && !disable) {
c.Ui.Error(c.Help())
return 1
}
// Check that we got a node ID
args = flags.Args()
if len(args) != 1 {
c.Ui.Error(c.Help())
return 1
}
nodeID := args[0]
// Get the HTTP client
client, err := c.Meta.Client()
if err != nil {
c.Ui.Error(fmt.Sprintf("Error initializing client: %s", err))
return 1
}
// Check if node exists
if len(nodeID) == 1 {
c.Ui.Error(fmt.Sprintf("Identifier must contain at least two characters."))
return 1
}
if len(nodeID)%2 == 1 {
// Identifiers must be of even length, so we strip off the last byte
// to provide a consistent user experience.
nodeID = nodeID[:len(nodeID)-1]
}
// Exact lookup failed, try with prefix based search
nodes, _, err := client.Nodes().PrefixList(nodeID)
if err != nil {
c.Ui.Error(fmt.Sprintf("Error toggling drain mode: %s", err))
return 1
}
// Return error if no nodes are found
if len(nodes) == 0 {
c.Ui.Error(fmt.Sprintf("No node(s) with prefix or id %q found", nodeID))
return 1
}
if len(nodes) > 1 {
// Format the nodes list that matches the prefix so that the user
// can create a more specific request
out := make([]string, len(nodes)+1)
out[0] = "ID|Datacenter|Name|Class|Drain|Status"
for i, node := range nodes {
out[i+1] = fmt.Sprintf("%s|%s|%s|%s|%v|%s",
node.ID,
node.Datacenter,
node.Name,
node.NodeClass,
node.Drain,
node.Status)
}
// Dump the output
c.Ui.Output(fmt.Sprintf("Prefix matched multiple nodes\n\n%s", formatList(out)))
return 0
}
// Prefix lookup matched a single node
node, _, err := client.Nodes().Info(nodes[0].ID, nil)
if err != nil {
c.Ui.Error(fmt.Sprintf("Error toggling drain mode: %s", err))
return 1
}
// Confirm drain if the node was a prefix match.
if nodeID != node.ID && !autoYes {
verb := "enable"
if disable {
verb = "disable"
}
question := fmt.Sprintf("Are you sure you want to %s drain mode for node %q? [y/N]", verb, node.ID)
answer, err := c.Ui.Ask(question)
if err != nil {
c.Ui.Error(fmt.Sprintf("Failed to parse answer: %v", err))
return 1
}
if answer == "" || strings.ToLower(answer)[0] == 'n' {
// No case
c.Ui.Output("Canceling drain toggle")
return 0
} else if strings.ToLower(answer)[0] == 'y' {
// Non exact match yes
c.Ui.Output("For confirmation, an exact y is required.")
return 0
} else if answer != "y" {
c.Ui.Output("No confirmation detected. For confirmation, an exact 'y' is required.")
return 1
}
}
// Toggle node draining
if _, err := client.Nodes().ToggleDrain(node.ID, enable, nil); err != nil {
c.Ui.Error(fmt.Sprintf("Error toggling drain mode: %s", err))
return 1
}
return 0
}