d30ff6cfae
Instead of constantly making these updates, let's just remove the year since things are stored in git anyways, and this is not an actual modern legal risk anymore.
97 lines
3.2 KiB
Go
97 lines
3.2 KiB
Go
// Mgmt
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// Copyright (C) James Shubin and the project contributors
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// Written by James Shubin <james@shubin.ca> and the project contributors
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//
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// This program is free software: you can redistribute it and/or modify
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// it under the terms of the GNU General Public License as published by
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// the Free Software Foundation, either version 3 of the License, or
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// (at your option) any later version.
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//
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// This program is distributed in the hope that it will be useful,
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// but WITHOUT ANY WARRANTY; without even the implied warranty of
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// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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// GNU General Public License for more details.
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//
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// You should have received a copy of the GNU General Public License
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// along with this program. If not, see <https://www.gnu.org/licenses/>.
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//
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// Additional permission under GNU GPL version 3 section 7
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//
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// If you modify this program, or any covered work, by linking or combining it
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// with embedded mcl code and modules (and that the embedded mcl code and
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// modules which link with this program, contain a copy of their source code in
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// the authoritative form) containing parts covered by the terms of any other
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// license, the licensors of this program grant you additional permission to
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// convey the resulting work. Furthermore, the licensors of this program grant
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// the original author, James Shubin, additional permission to update this
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// additional permission if he deems it necessary to achieve the goals of this
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// additional permission.
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package scheduler // TODO: i'd like this to be a separate package, but cycles!
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import (
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"fmt"
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"sort"
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"github.com/purpleidea/mgmt/util"
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)
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func init() {
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Register("rr", func() Strategy { return &rrStrategy{} }) // must register the func and name
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}
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type rrStrategy struct {
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// some stored state
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hosts []string
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}
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// Schedule returns hosts in round robin style from the available hostnames.
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func (obj *rrStrategy) Schedule(hostnames map[string]string, opts *schedulerOptions) ([]string, error) {
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if len(hostnames) <= 0 {
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return nil, fmt.Errorf("strategy: cannot schedule from zero hosts")
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}
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if opts.maxCount <= 0 {
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return nil, fmt.Errorf("strategy: cannot schedule with a max of zero")
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}
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// always get a deterministic list of current hosts first...
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sortedHosts := []string{}
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for key := range hostnames {
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sortedHosts = append(sortedHosts, key)
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}
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sort.Strings(sortedHosts)
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if obj.hosts == nil {
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obj.hosts = []string{} // initialize if needed
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}
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// add any new hosts we learned about, to the end of the list
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for _, x := range sortedHosts {
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if !util.StrInList(x, obj.hosts) {
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obj.hosts = append(obj.hosts, x)
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}
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}
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// remove any hosts we previouly knew about from the list
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for ix := len(obj.hosts) - 1; ix >= 0; ix-- {
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if !util.StrInList(obj.hosts[ix], sortedHosts) {
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// delete entry at this index
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obj.hosts = append(obj.hosts[:ix], obj.hosts[ix+1:]...)
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}
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}
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// get the maximum number of hosts to return
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max := len(obj.hosts) // can't return more than we have
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if opts.maxCount < max { // found a smaller limit
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max = opts.maxCount
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}
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result := []string{}
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// now return the number of needed hosts from the list
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for i := 0; i < max; i++ {
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result = append(result, obj.hosts[i])
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}
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return result, nil
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}
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