76 lines
1.6 KiB
Go
76 lines
1.6 KiB
Go
package filter
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import (
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"fmt"
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"github.com/bdlm/log"
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"github.com/pkg/errors"
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"github.com/FreifunkBremen/yanic/runtime"
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)
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// factory function for building a filter
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// may return nil if the filter never applies
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type factory func(interface{}) (Filter, error)
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// Filter is a filter instance
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type Filter interface {
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Apply(*runtime.Node) *runtime.Node
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}
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// Set is a list of configured filters
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type Set []Filter
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var filters = make(map[string]factory)
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// Register registers a new filter
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func Register(name string, f factory) {
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if _, ok := filters[name]; ok {
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log.WithField("filter", name).Panic("filter already registered")
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}
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filters[name] = f
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}
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// New returns and initializes a set of filters
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func New(configs map[string]interface{}) (set Set, errs []error) {
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for name, config := range configs {
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if config == nil {
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return
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}
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f := filters[name]
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if f == nil {
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errs = append(errs, fmt.Errorf("unknown filter: %s", name))
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} else if filter, err := f(config); err != nil {
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errs = append(errs, errors.Wrapf(err, "unable to initialize filter %s", name))
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} else if filter != nil {
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set = append(set, filter)
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}
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}
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return
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}
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// Apply applies the filter set to the given node list and returns a new node list
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func (set Set) Apply(nodesOrigin *runtime.Nodes) *runtime.Nodes {
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nodes := runtime.NewNodes(&runtime.NodesConfig{})
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nodesOrigin.Lock()
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defer nodesOrigin.Unlock()
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for _, nodeOrigin := range nodesOrigin.List {
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//maybe cloning of this object is better?
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node := nodeOrigin
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for _, filter := range set {
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node = filter.Apply(node)
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if node == nil {
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break
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}
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}
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if node != nil {
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nodes.AddNode(node)
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}
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}
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return nodes
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}
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