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.
52 lines
1.9 KiB
Go
52 lines
1.9 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
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import (
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"fmt"
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)
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// registeredStrategies is a global map of all possible strategy implementations
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// which can be used. You should never touch this map directly. Use methods like
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// Register instead.
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var registeredStrategies = make(map[string]func() Strategy) // must initialize
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// Strategy represents the methods a scheduler strategy must implement.
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type Strategy interface {
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Schedule(hostnames map[string]string, opts *schedulerOptions) ([]string, error)
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}
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// Register takes a func and its name and makes it available for use. It is
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// commonly called in the init() method of the func at program startup. There is
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// no matching Unregister function.
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func Register(name string, fn func() Strategy) {
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if _, ok := registeredStrategies[name]; ok {
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panic(fmt.Sprintf("a strategy named %s is already registered", name))
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}
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//gob.Register(fn())
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registeredStrategies[name] = fn
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}
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type nilStrategy struct {
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}
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// Schedule returns an error for any scheduling request for this nil strategy.
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func (obj *nilStrategy) Schedule(hostnames map[string]string, opts *schedulerOptions) ([]string, error) {
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return nil, fmt.Errorf("scheduler: cannot schedule with nil scheduler")
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}
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