87 lines
2.1 KiB
Go
87 lines
2.1 KiB
Go
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package templating
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import (
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"sort"
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"strings"
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)
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const (
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// DefaultSeparator is the default separation character to use when separating template parts.
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DefaultSeparator = "."
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)
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// Engine uses a Matcher to retrieve the appropriate template and applies the template
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// to the input string
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type Engine struct {
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joiner string
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matcher *matcher
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}
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// Apply extracts the template fields from the given line and returns the measurement
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// name, tags and field name
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func (e *Engine) Apply(line string) (string, map[string]string, string, error) {
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return e.matcher.match(line).Apply(line, e.joiner)
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}
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// NewEngine creates a new templating engine
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func NewEngine(joiner string, defaultTemplate *Template, templates []string) (*Engine, error) {
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engine := Engine{
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joiner: joiner,
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matcher: newMatcher(defaultTemplate),
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}
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templateSpecs := parseTemplateSpecs(templates)
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for _, templateSpec := range templateSpecs {
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if err := engine.matcher.addSpec(templateSpec); err != nil {
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return nil, err
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}
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}
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return &engine, nil
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}
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func parseTemplateSpecs(templates []string) templateSpecs {
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tmplts := templateSpecs{}
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for _, pattern := range templates {
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tmplt := templateSpec{
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separator: DefaultSeparator,
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}
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// Format is [separator] [filter] <template> [tag1=value1,tag2=value2]
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parts := strings.Fields(pattern)
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partsLength := len(parts)
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if partsLength < 1 {
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// ignore
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continue
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}
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if partsLength == 1 {
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tmplt.template = pattern
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} else if partsLength == 4 {
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tmplt.separator = parts[0]
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tmplt.filter = parts[1]
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tmplt.template = parts[2]
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tmplt.tagstring = parts[3]
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} else {
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hasTagstring := strings.Contains(parts[partsLength-1], "=")
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if hasTagstring {
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tmplt.tagstring = parts[partsLength-1]
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tmplt.template = parts[partsLength-2]
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if partsLength == 3 {
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tmplt.filter = parts[0]
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}
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} else {
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tmplt.template = parts[partsLength-1]
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if partsLength == 2 {
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tmplt.filter = parts[0]
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} else { // length == 3
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tmplt.separator = parts[0]
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tmplt.filter = parts[1]
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}
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}
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}
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tmplts = append(tmplts, tmplt)
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}
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sort.Sort(tmplts)
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return tmplts
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}
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