79 lines
2.1 KiB
Go
79 lines
2.1 KiB
Go
package config
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import (
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"crypto/sha256"
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"encoding/hex"
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"fmt"
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"sort"
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"github.com/influxdata/toml/ast"
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)
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type keyValuePair struct {
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Key string
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Value string
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}
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func processTable(parent string, table *ast.Table) ([]keyValuePair, error) {
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var prefix string
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var options []keyValuePair
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if parent != "" {
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prefix = parent + "."
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}
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for k, value := range table.Fields {
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switch v := value.(type) {
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case *ast.KeyValue:
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key := prefix + k
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options = append(options, keyValuePair{
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Key: key,
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Value: v.Value.Source(),
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})
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case *ast.Table:
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key := prefix + k
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children, err := processTable(key, v)
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if err != nil {
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return nil, fmt.Errorf("parsing table for %q failed: %w", key, err)
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}
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options = append(options, children...)
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case []*ast.Table:
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for i, t := range v {
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key := fmt.Sprintf("%s#%d.%s", prefix, i, k)
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children, err := processTable(key, t)
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if err != nil {
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return nil, fmt.Errorf("parsing table for %q #%d failed: %w", key, i, err)
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}
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options = append(options, children...)
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}
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default:
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return nil, fmt.Errorf("unknown node type %T in key %q", value, prefix+k)
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}
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}
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return options, nil
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}
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func generatePluginID(prefix string, table *ast.Table) (string, error) {
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// We need to ensure that identically configured plugins _always_
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// result in the same ID no matter which order the options are specified.
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// This is even more relevant as Golang does _not_ give any guarantee
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// on the ordering of maps.
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// So we flatten out the configuration options (also for nested objects)
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// and then sort the resulting array by the canonical key-name.
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cfg, err := processTable("", table)
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if err != nil {
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return "", fmt.Errorf("processing AST failed: %w", err)
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}
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sort.SliceStable(cfg, func(i, j int) bool { return cfg[i].Key < cfg[j].Key })
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// Hash the config options to get the ID. We also prefix the ID with
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// the plugin name to prevent overlap with other plugin types.
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hash := sha256.New()
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hash.Write(append([]byte(prefix), 0))
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for _, kv := range cfg {
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hash.Write([]byte(kv.Key + ":" + kv.Value))
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hash.Write([]byte{0})
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}
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return hex.EncodeToString(hash.Sum(nil)), nil
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}
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