traefik/pkg/config/parser/labels_decode.go

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package parser
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import (
"fmt"
"sort"
"strings"
)
const labelRoot = "traefik"
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// DecodeToNode converts the labels to a tree of nodes.
// If any filters are present, labels which do not match the filters are skipped.
func DecodeToNode(labels map[string]string, filters ...string) (*Node, error) {
sortedKeys := sortKeys(labels, filters)
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var node *Node
for i, key := range sortedKeys {
split := strings.Split(key, ".")
if split[0] != labelRoot {
return nil, fmt.Errorf("invalid label root %s", split[0])
}
var parts []string
for _, v := range split {
if v[0] == '[' {
return nil, fmt.Errorf("invalid leading character '[' in field name (bracket is a slice delimiter): %s", v)
}
if strings.HasSuffix(v, "]") && v[0] != '[' {
indexLeft := strings.Index(v, "[")
parts = append(parts, v[:indexLeft], v[indexLeft:])
} else {
parts = append(parts, v)
}
}
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if i == 0 {
node = &Node{}
}
decodeToNode(node, parts, labels[key])
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}
return node, nil
}
func decodeToNode(root *Node, path []string, value string) {
if len(root.Name) == 0 {
root.Name = path[0]
}
// it's a leaf or not -> children
if len(path) > 1 {
if n := containsNode(root.Children, path[1]); n != nil {
// the child already exists
decodeToNode(n, path[1:], value)
} else {
// new child
child := &Node{Name: path[1]}
decodeToNode(child, path[1:], value)
root.Children = append(root.Children, child)
}
} else {
root.Value = value
}
}
func containsNode(nodes []*Node, name string) *Node {
for _, n := range nodes {
if name == n.Name {
return n
}
}
return nil
}
func sortKeys(labels map[string]string, filters []string) []string {
var sortedKeys []string
for key := range labels {
if len(filters) == 0 {
sortedKeys = append(sortedKeys, key)
continue
}
for _, filter := range filters {
if len(key) >= len(filter) && strings.EqualFold(key[:len(filter)], filter) {
sortedKeys = append(sortedKeys, key)
continue
}
}
}
sort.Strings(sortedKeys)
return sortedKeys
}