mirror of
https://github.com/prometheus/prometheus.git
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738af32057
Currently missing values will get the value <no value> rather than the empty string. Using the empty string is more consistent, and should be easier for users to deal with too.
326 lines
8.8 KiB
Go
326 lines
8.8 KiB
Go
// Copyright 2013 The Prometheus Authors
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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package template
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import (
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"bytes"
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"errors"
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"fmt"
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"math"
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"regexp"
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"sort"
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"strings"
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html_template "html/template"
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text_template "text/template"
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"github.com/prometheus/common/model"
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"github.com/prometheus/prometheus/promql"
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"github.com/prometheus/prometheus/util/strutil"
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)
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// A version of vector that's easier to use from templates.
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type sample struct {
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Labels map[string]string
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Value float64
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}
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type queryResult []*sample
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type queryResultByLabelSorter struct {
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results queryResult
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by string
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}
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func (q queryResultByLabelSorter) Len() int {
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return len(q.results)
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}
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func (q queryResultByLabelSorter) Less(i, j int) bool {
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return q.results[i].Labels[q.by] < q.results[j].Labels[q.by]
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}
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func (q queryResultByLabelSorter) Swap(i, j int) {
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q.results[i], q.results[j] = q.results[j], q.results[i]
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}
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func query(q string, timestamp model.Time, queryEngine *promql.Engine) (queryResult, error) {
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query, err := queryEngine.NewInstantQuery(q, timestamp)
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if err != nil {
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return nil, err
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}
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res := query.Exec()
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if res.Err != nil {
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return nil, res.Err
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}
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var vector model.Vector
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switch v := res.Value.(type) {
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case model.Matrix:
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return nil, errors.New("matrix return values not supported")
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case model.Vector:
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vector = v
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case *model.Scalar:
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vector = model.Vector{&model.Sample{
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Value: v.Value,
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Timestamp: v.Timestamp,
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}}
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case *model.String:
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vector = model.Vector{&model.Sample{
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Metric: model.Metric{"__value__": model.LabelValue(v.Value)},
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Timestamp: v.Timestamp,
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}}
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default:
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panic("template.query: unhandled result value type")
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}
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// promql.Vector is hard to work with in templates, so convert to
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// base data types.
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var result = make(queryResult, len(vector))
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for n, v := range vector {
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s := sample{
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Value: float64(v.Value),
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Labels: make(map[string]string),
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}
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for label, value := range v.Metric {
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s.Labels[string(label)] = string(value)
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}
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result[n] = &s
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}
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return result, nil
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}
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// Expander executes templates in text or HTML mode with a common set of Prometheus template functions.
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type Expander struct {
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text string
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name string
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data interface{}
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funcMap text_template.FuncMap
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}
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// NewTemplateExpander returns a template expander ready to use.
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func NewTemplateExpander(text string, name string, data interface{}, timestamp model.Time, queryEngine *promql.Engine, pathPrefix string) *Expander {
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return &Expander{
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text: text,
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name: name,
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data: data,
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funcMap: text_template.FuncMap{
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"query": func(q string) (queryResult, error) {
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return query(q, timestamp, queryEngine)
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},
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"first": func(v queryResult) (*sample, error) {
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if len(v) > 0 {
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return v[0], nil
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}
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return nil, errors.New("first() called on vector with no elements")
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},
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"label": func(label string, s *sample) string {
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return s.Labels[label]
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},
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"value": func(s *sample) float64 {
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return s.Value
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},
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"strvalue": func(s *sample) string {
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return s.Labels["__value__"]
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},
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"args": func(args ...interface{}) map[string]interface{} {
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result := make(map[string]interface{})
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for i, a := range args {
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result[fmt.Sprintf("arg%d", i)] = a
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}
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return result
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},
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"reReplaceAll": func(pattern, repl, text string) string {
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re := regexp.MustCompile(pattern)
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return re.ReplaceAllString(text, repl)
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},
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"safeHtml": func(text string) html_template.HTML {
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return html_template.HTML(text)
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},
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"match": regexp.MatchString,
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"title": strings.Title,
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"graphLink": strutil.GraphLinkForExpression,
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"tableLink": strutil.TableLinkForExpression,
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"sortByLabel": func(label string, v queryResult) queryResult {
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sorter := queryResultByLabelSorter{v[:], label}
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sort.Stable(sorter)
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return v
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},
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"humanize": func(v float64) string {
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if v == 0 || math.IsNaN(v) || math.IsInf(v, 0) {
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return fmt.Sprintf("%.4g", v)
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}
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if math.Abs(v) >= 1 {
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prefix := ""
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for _, p := range []string{"k", "M", "G", "T", "P", "E", "Z", "Y"} {
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if math.Abs(v) < 1000 {
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break
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}
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prefix = p
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v /= 1000
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}
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return fmt.Sprintf("%.4g%s", v, prefix)
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}
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prefix := ""
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for _, p := range []string{"m", "u", "n", "p", "f", "a", "z", "y"} {
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if math.Abs(v) >= 1 {
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break
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}
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prefix = p
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v *= 1000
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}
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return fmt.Sprintf("%.4g%s", v, prefix)
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},
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"humanize1024": func(v float64) string {
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if math.Abs(v) <= 1 || math.IsNaN(v) || math.IsInf(v, 0) {
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return fmt.Sprintf("%.4g", v)
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}
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prefix := ""
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for _, p := range []string{"ki", "Mi", "Gi", "Ti", "Pi", "Ei", "Zi", "Yi"} {
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if math.Abs(v) < 1024 {
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break
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}
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prefix = p
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v /= 1024
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}
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return fmt.Sprintf("%.4g%s", v, prefix)
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},
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"humanizeDuration": func(v float64) string {
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if math.IsNaN(v) || math.IsInf(v, 0) {
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return fmt.Sprintf("%.4g", v)
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}
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if v == 0 {
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return fmt.Sprintf("%.4gs", v)
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}
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if math.Abs(v) >= 1 {
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sign := ""
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if v < 0 {
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sign = "-"
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v = -v
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}
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seconds := int64(v) % 60
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minutes := (int64(v) / 60) % 60
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hours := (int64(v) / 60 / 60) % 24
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days := (int64(v) / 60 / 60 / 24)
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// For days to minutes, we display seconds as an integer.
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if days != 0 {
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return fmt.Sprintf("%s%dd %dh %dm %ds", sign, days, hours, minutes, seconds)
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}
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if hours != 0 {
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return fmt.Sprintf("%s%dh %dm %ds", sign, hours, minutes, seconds)
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}
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if minutes != 0 {
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return fmt.Sprintf("%s%dm %ds", sign, minutes, seconds)
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}
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// For seconds, we display 4 significant digts.
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return fmt.Sprintf("%s%.4gs", sign, v)
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}
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prefix := ""
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for _, p := range []string{"m", "u", "n", "p", "f", "a", "z", "y"} {
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if math.Abs(v) >= 1 {
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break
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}
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prefix = p
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v *= 1000
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}
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return fmt.Sprintf("%.4g%ss", v, prefix)
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},
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"humanizeTimestamp": func(v float64) string {
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if math.IsNaN(v) || math.IsInf(v, 0) {
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return fmt.Sprintf("%.4g", v)
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}
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t := model.TimeFromUnixNano(int64(v * 1e9)).Time().UTC()
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return fmt.Sprint(t)
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},
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"pathPrefix": func() string {
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return pathPrefix
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},
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},
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}
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}
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// Funcs adds the functions in fm to the Expander's function map.
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// Existing functions will be overwritten in case of conflict.
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func (te Expander) Funcs(fm text_template.FuncMap) {
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for k, v := range fm {
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te.funcMap[k] = v
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}
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}
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// Expand expands a template in text (non-HTML) mode.
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func (te Expander) Expand() (result string, resultErr error) {
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// It'd better to have no alert description than to kill the whole process
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// if there's a bug in the template.
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defer func() {
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if r := recover(); r != nil {
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var ok bool
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resultErr, ok = r.(error)
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if !ok {
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resultErr = fmt.Errorf("panic expanding template %v: %v", te.name, r)
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}
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}
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}()
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tmpl, err := text_template.New(te.name).Funcs(te.funcMap).Parse(te.text)
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tmpl.Option("missingkey=zero")
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if err != nil {
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return "", fmt.Errorf("error parsing template %v: %v", te.name, err)
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}
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var buffer bytes.Buffer
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err = tmpl.Execute(&buffer, te.data)
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if err != nil {
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return "", fmt.Errorf("error executing template %v: %v", te.name, err)
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}
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return buffer.String(), nil
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}
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// ExpandHTML expands a template with HTML escaping, with templates read from the given files.
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func (te Expander) ExpandHTML(templateFiles []string) (result string, resultErr error) {
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defer func() {
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if r := recover(); r != nil {
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var ok bool
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resultErr, ok = r.(error)
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if !ok {
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resultErr = fmt.Errorf("panic expanding template %v: %v", te.name, r)
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}
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}
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}()
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tmpl := html_template.New(te.name).Funcs(html_template.FuncMap(te.funcMap))
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tmpl.Option("missingkey=zero")
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tmpl.Funcs(html_template.FuncMap{
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"tmpl": func(name string, data interface{}) (html_template.HTML, error) {
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var buffer bytes.Buffer
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err := tmpl.ExecuteTemplate(&buffer, name, data)
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return html_template.HTML(buffer.String()), err
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},
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})
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tmpl, err := tmpl.Parse(te.text)
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if err != nil {
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return "", fmt.Errorf("error parsing template %v: %v", te.name, err)
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}
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if len(templateFiles) > 0 {
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_, err = tmpl.ParseFiles(templateFiles...)
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if err != nil {
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return "", fmt.Errorf("error parsing template files for %v: %v", te.name, err)
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}
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}
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var buffer bytes.Buffer
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err = tmpl.Execute(&buffer, te.data)
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if err != nil {
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return "", fmt.Errorf("error executing template %v: %v", te.name, err)
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}
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return buffer.String(), nil
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}
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