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/
state.go
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/
state.go
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// Copyright 2014 CoreOS, Inc.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
package agent
import (
"fmt"
"path"
"github.com/coreos/fleet/job"
"github.com/coreos/fleet/log"
"github.com/coreos/fleet/machine"
)
type AgentState struct {
MState *machine.MachineState
Units map[string]*job.Unit
}
func NewAgentState(ms *machine.MachineState) *AgentState {
return &AgentState{
MState: ms,
Units: make(map[string]*job.Unit),
}
}
func (as *AgentState) unitScheduled(name string) bool {
return as.Units[name] != nil
}
// hasConflict determines whether there are any known conflicts with the given Unit
func (as *AgentState) hasConflict(pUnitName string, pConflicts []string) (found bool, conflict string) {
for _, eUnit := range as.Units {
if pUnitName == eUnit.Name {
continue
}
for _, pConflict := range pConflicts {
if globMatches(pConflict, eUnit.Name) {
found = true
conflict = eUnit.Name
return
}
}
for _, eConflict := range eUnit.Conflicts() {
if globMatches(eConflict, pUnitName) {
found = true
conflict = eUnit.Name
return
}
}
}
return
}
// hasReplace determines whether there are any known replaces with the given Unit
func (as *AgentState) hasReplace(pUnitName string, pReplaces []string) (found bool, replace string) {
for _, eUnit := range as.Units {
foundPrepl := false
foundErepl := false
retStr := ""
if pUnitName == eUnit.Name {
continue
}
for _, pReplace := range pReplaces {
if globMatches(pReplace, eUnit.Name) {
foundPrepl = true
retStr = eUnit.Name
break
}
}
for _, eReplace := range eUnit.Replaces() {
if globMatches(eReplace, pUnitName) {
foundErepl = true
retStr = eUnit.Name
break
}
}
// Only 1 of 2 matches must be found. If both matches are found,
// it means it's a circular replace situation, which could result in
// an infinite loop. So ignore such replace options.
if (foundPrepl && foundErepl) || (!foundPrepl && !foundErepl) {
continue
} else {
found = true
replace = retStr
return
}
}
return
}
func globMatches(pattern, target string) bool {
matched, err := path.Match(pattern, target)
if err != nil {
log.Debugf("Received error while matching pattern '%s': %v", pattern, err)
}
return matched
}
// AbleToRun determines if an Agent can run the provided Job based on
// the Agent's current state. A boolean indicating whether this is the
// case or not is returned. The following criteria is used:
// - Agent must meet the Job's machine target requirement (if any)
// - Agent must have all of the Job's required metadata (if any)
// - Agent must have all required Peers of the Job scheduled locally (if any)
// - Job must not conflict with any other Units scheduled to the agent
// - Job must specially handle replaced units to be rescheduled
func (as *AgentState) AbleToRun(j *job.Job) (bool, string) {
if tgt, ok := j.RequiredTarget(); ok && !as.MState.MatchID(tgt) {
return false, fmt.Sprintf("agent ID %q does not match required %q", as.MState.ID, tgt)
}
metadata := j.RequiredTargetMetadata()
if len(metadata) != 0 {
if !machine.HasMetadata(as.MState, metadata) {
return false, "local Machine metadata insufficient"
}
}
peers := j.Peers()
if len(peers) != 0 {
for _, peer := range peers {
if !as.unitScheduled(peer) {
return false, fmt.Sprintf("required peer Unit(%s) is not scheduled locally", peer)
}
}
}
if cExists, cJobName := as.hasConflict(j.Name, j.Conflicts()); cExists {
return false, fmt.Sprintf("found conflict with locally-scheduled Unit(%s)", cJobName)
}
// Handle Replace option specially, by returning a special string
// "jobreschedule" as reason.
if cExists, _ := as.hasReplace(j.Name, j.Replaces()); cExists {
return false, job.JobReschedule
}
return true, ""
}