/
meterstatus.go
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/
meterstatus.go
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// Copyright 2014 Canonical Ltd.
// Licensed under the AGPLv3, see LICENCE file for details.
package state
import (
"github.com/juju/errors"
"github.com/juju/mgo/v3/bson"
"github.com/juju/mgo/v3/txn"
jujutxn "github.com/juju/txn/v3"
)
// MeterStatus represents the metering status of a unit.
type MeterStatus struct {
Code MeterStatusCode
Info string
}
// Severity returns relative severity of the meter status.
func (m *MeterStatus) Severity() int {
return m.Code.Severity()
}
// MeterStatusCode represents the meter status code of a unit.
// The int value represents its relative severity when compared to
// other MeterStatusCodes.
type MeterStatusCode int
// Severity returns the relative severity.
func (m MeterStatusCode) Severity() int {
return int(m)
}
// String returns a human readable string representation of the meter status.
func (m MeterStatusCode) String() string {
s, ok := meterString[m]
if !ok {
return MeterNotAvailable.String()
}
return s
}
// MeterStatusFromString returns a valid MeterStatusCode given a string representation.
func MeterStatusFromString(str string) MeterStatusCode {
for m, s := range meterString {
if s == str {
return m
}
}
return MeterNotAvailable
}
// This const block defines the relative severities of the valid MeterStatusCodes in ascending order.
const (
MeterNotAvailable MeterStatusCode = iota
MeterRed
MeterAmber
MeterNotSet
MeterGreen
)
var (
meterString = map[MeterStatusCode]string{
MeterGreen: "GREEN",
MeterNotSet: "NOT SET",
MeterAmber: "AMBER",
MeterNotAvailable: "NOT AVAILABLE",
MeterRed: "RED",
}
)
type meterStatusDoc struct {
DocID string `bson:"_id"`
ModelUUID string `bson:"model-uuid"`
Code string `bson:"code"`
Info string `bson:"info"`
}
func isValidMeterStatusCode(codeStr string) (MeterStatusCode, error) {
code := MeterStatusFromString(codeStr)
switch code {
case MeterGreen, MeterAmber, MeterRed:
return code, nil
default:
return MeterNotAvailable, errors.NotValidf("meter status %q", codeStr)
}
}
// SetMeterStatus sets the meter status for the unit.
func (u *Unit) SetMeterStatus(codeStr, info string) error {
code, err := isValidMeterStatusCode(codeStr)
if err != nil {
return errors.Trace(err)
}
meterDoc, err := u.getMeterStatusDoc()
if err != nil {
return errors.Annotatef(err, "cannot update meter status for unit %s", u.Name())
}
if meterDoc.Code == code.String() && meterDoc.Info == info {
return nil
}
buildTxn := func(attempt int) ([]txn.Op, error) {
if attempt > 0 {
err := u.Refresh()
if err != nil {
return nil, errors.Trace(err)
}
meterDoc, err = u.getMeterStatusDoc()
if err != nil {
return nil, errors.Annotatef(err, "cannot update meter status for unit %s", u.Name())
}
if meterDoc.Code == code.String() && meterDoc.Info == info {
return nil, jujutxn.ErrNoOperations
}
}
return []txn.Op{
{
C: unitsC,
Id: u.doc.DocID,
Assert: isAliveDoc,
}, {
C: meterStatusC,
Id: u.st.docID(u.globalMeterStatusKey()),
Assert: txn.DocExists,
Update: bson.D{{"$set", bson.D{{"code", code.String()}, {"info", info}}}},
}}, nil
}
return errors.Annotatef(u.st.db().Run(buildTxn), "cannot set meter state for unit %s", u.Name())
}
// createMeterStatusOp returns the operation needed to create the meter status
// document associated with the given globalKey.
func createMeterStatusOp(mb modelBackend, globalKey string, doc *meterStatusDoc) txn.Op {
doc.ModelUUID = mb.ModelUUID()
return txn.Op{
C: meterStatusC,
Id: mb.docID(globalKey),
Assert: txn.DocMissing,
Insert: doc,
}
}
// removeMeterStatusOp returns the operation needed to remove the meter status
// document associated with the given globalKey.
func removeMeterStatusOp(mb modelBackend, globalKey string) txn.Op {
return txn.Op{
C: meterStatusC,
Id: mb.docID(globalKey),
Remove: true,
}
}
// GetMeterStatus returns the meter status for the unit.
func (u *Unit) GetMeterStatus() (MeterStatus, error) {
mm, err := u.st.MetricsManager()
if err != nil {
return MeterStatus{MeterNotAvailable, ""}, errors.Annotatef(err, "cannot retrieve meter status for metrics manager")
}
mmStatus := mm.MeterStatus()
if mmStatus.Code == MeterRed {
return mmStatus, nil
}
status, err := u.getMeterStatusDoc()
if err != nil {
return MeterStatus{MeterNotAvailable, ""}, errors.Annotatef(err, "cannot retrieve meter status for unit %s", u.Name())
}
code := MeterStatusFromString(status.Code)
unitMeterStatus := MeterStatus{code, status.Info}
return combineMeterStatus(mmStatus, unitMeterStatus), nil
}
func combineMeterStatus(a, b MeterStatus) MeterStatus {
if a.Severity() < b.Severity() {
return a
}
return b
}
func (u *Unit) getMeterStatusDoc() (*meterStatusDoc, error) {
meterStatuses, closer := u.st.db().GetCollection(meterStatusC)
defer closer()
var status meterStatusDoc
err := meterStatuses.FindId(u.globalMeterStatusKey()).One(&status)
if err != nil {
return nil, errors.Trace(err)
}
return &status, nil
}