time_series.go

package search

import (
	"bytes"
	"context"
	"encoding/json"
	"io/ioutil"
	"net/http"
	"reflect"
	"strings"
	"time"

	opensearchapi "github.com/opensearch-project/opensearch-go/opensearchapi"
	"gitlab.com/uafrica/go-utils/errors"
	"gitlab.com/uafrica/go-utils/logger"
	"gitlab.com/uafrica/go-utils/reflection"
)

const TimeFormat = "2006-01-02T15:04:05Z07:00"

//embed this into your log struct
type TimeSeriesHeader struct {
	StartTime  time.Time `json:"@timestamp"`
	EndTime    time.Time `json:"@end_time"`
	DurationMs int64     `json:"@duration_ms"`
}

type TimeSeries interface {
	Write(StartTime time.Time, EndTime time.Time, data interface{}) error

	//Search() returns docs indexed on OpenSearch document ID which cat be used in Get(id)
	//The docs value type is the same as that of tmpl specified when you created the TimeSeries(..., tmpl)
	//So you can safely type assert e.g.
	//		type myType struct {...}
	//		ts := search.TimeSeries(..., myType{})
	//		docs,totalCount,err := ts.Search(...)
	//		if err == nil {
	//			for id,docValue := range docs {
	//				doc := docValue.(myType)
	//				...
	//			}
	//		}
	Search(query Query, limit int64) (docs map[string]interface{}, totalCount int, err error)

	//Get() takes the id returned in Search()
	//The id is uuid assigned by OpenSearch when documents are added with Write().
	//The document value type is the same as that of tmpl specified when you created the TimeSeries(..., tmpl)
	Get(id string) (interface{}, error)
}

type timeSeries struct {
	w            *writer
	name         string
	dataType     reflect.Type
	settings     Settings
	mappings     Mappings
	jsonSettings []byte
	jsonMappings []byte
	createdDates map[string]bool

	searchResponseBodyType reflect.Type
}

//purpose:
//	create a time series to write e.g. api logs
//parameters:
//	name must be the openSearch index name prefix without the date, e.g. "uafrica-v3-api-logs"
//		the actual indices in openSearch will be called "<indexName>-<ccyymmdd>" e.g. "uafrica-v3-api-logs-20210102"
//	tmpl must be your log data struct consisting of public fields as:
//		Xxx string `json:"<name>" search:"keyword|text|long|date"`	(can later add more types)