b19583e7d3
This is an initial implementation of the mgmt language. It is a declarative (immutable) functional, reactive, domain specific programming language. It is intended to be a language that is: * safe * powerful * easy to reason about With these properties, we hope this language, and the mgmt engine will allow you to model the real-time systems that you'd like to automate. This also includes a number of other associated changes. Sorry for the large size of this patch.
50 lines
1.6 KiB
Go
50 lines
1.6 KiB
Go
// Mgmt
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// Copyright (C) 2013-2018+ 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 <http://www.gnu.org/licenses/>.
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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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)
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func init() {
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Register("alpha", func() Strategy { return &alphaStrategy{} }) // must register the func and name
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}
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type alphaStrategy struct {
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// no state to store
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}
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// Schedule returns the first host out of a sorted group of available hostnames.
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func (obj *alphaStrategy) 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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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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return []string{sortedHosts[0]}, nil // pick first host
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}
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