open-nomad/client/util.go

116 lines
2.8 KiB
Go

package client
import (
"encoding/json"
"fmt"
"io/ioutil"
"math/rand"
"os"
"path/filepath"
"time"
"github.com/hashicorp/nomad/nomad/structs"
)
type allocTuple struct {
exist, updated *structs.Allocation
}
// diffResult is used to return the sets that result from a diff
type diffResult struct {
added []*structs.Allocation
removed []*structs.Allocation
updated []allocTuple
ignore []*structs.Allocation
}
func (d *diffResult) GoString() string {
return fmt.Sprintf("allocs: (added %d) (removed %d) (updated %d) (ignore %d)",
len(d.added), len(d.removed), len(d.updated), len(d.ignore))
}
// diffAllocs is used to diff the existing and updated allocations
// to see what has happened.
func diffAllocs(existing, updated []*structs.Allocation) *diffResult {
result := &diffResult{}
// Index the updated allocations by id
idx := make(map[string]*structs.Allocation)
for _, update := range updated {
idx[update.ID] = update
}
// Scan the existing allocations
existIdx := make(map[string]struct{})
for _, exist := range existing {
// Mark this as existing
existIdx[exist.ID] = struct{}{}
// Check for presence in the new set
update, ok := idx[exist.ID]
// If not present, removed
if !ok {
result.removed = append(result.removed, exist)
continue
}
// Check for an update
if update.ModifyIndex > exist.ModifyIndex {
result.updated = append(result.updated, allocTuple{exist, update})
continue
}
// Ignore this
result.ignore = append(result.ignore, exist)
}
// Scan the updated allocations for any that are new
for _, update := range updated {
if _, ok := existIdx[update.ID]; !ok {
result.added = append(result.added, update)
}
}
return result
}
// Returns a random stagger interval between 0 and the duration
func randomStagger(intv time.Duration) time.Duration {
return time.Duration(uint64(rand.Int63()) % uint64(intv))
}
// shuffleStrings randomly shuffles the list of strings
func shuffleStrings(list []string) {
for i := range list {
j := rand.Intn(i + 1)
list[i], list[j] = list[j], list[i]
}
}
// persistState is used to help with saving state
func persistState(path string, data interface{}) error {
buf, err := json.Marshal(data)
if err != nil {
return fmt.Errorf("failed to encode state: %v", err)
}
if err := os.MkdirAll(filepath.Dir(path), 0700); err != nil {
return fmt.Errorf("failed to make dirs for %s: %v", path, err)
}
if err := ioutil.WriteFile(path, buf, 0600); err != nil {
return fmt.Errorf("failed to save state: %v", err)
}
return nil
}
// restoreState is used to read back in the persisted state
func restoreState(path string, data interface{}) error {
buf, err := ioutil.ReadFile(path)
if err != nil {
return fmt.Errorf("failed to read state: %v", err)
}
if err := json.Unmarshal(buf, data); err != nil {
return fmt.Errorf("failed to decode state: %v", err)
}
return nil
}