Getting started with Elastic v6

package main

import ( "context" "encoding/json" "fmt" "reflect"

"github.com/olivere/elastic"

)

type Tweet struct { User string json:"user" Message string json:"message" }

func main() { // Create a client client, err := elastic.NewClient() if err != nil { // Handle error }

// Create an index
_, err = client.CreateIndex("tweets").Do(context.Background())
if err != nil {
	// Handle error
	panic(err)
}

// Add a document to the index
tweet := Tweet{User: "olivere", Message: "Take Five"}
_, err = client.Index().
	Index("tweets").
	Type("doc").
	Id("1").
	BodyJson(tweet).
	Refresh("wait_for").
	Do(context.Background())
if err != nil {
	// Handle error
	panic(err)
}

// Search with a term query
termQuery := elastic.NewTermQuery("user", "olivere")
searchResult, err := client.Search().
	Index("tweets").            // search in index "tweets"
	Query(termQuery).           // specify the query
	Sort("user.keyword", true). // sort by "user" field, ascending
	From(0).Size(10).           // take documents 0-9
	Pretty(true).               // pretty print request and response JSON
	Do(context.Background())    // execute
if err != nil {
	// Handle error
	panic(err)
}

// searchResult is of type SearchResult and returns hits, suggestions,
// and all kinds of other information from Elasticsearch.
fmt.Printf("Query took %d milliseconds\n", searchResult.TookInMillis)

// Each is a convenience function that iterates over hits in a search result.
// It makes sure you don't need to check for nil values in the response.
// However, it ignores errors in serialization. If you want full control
// over iterating the hits, see below.
var ttyp Tweet
for _, item := range searchResult.Each(reflect.TypeOf(ttyp)) {
	if t, ok := item.(Tweet); ok {
		fmt.Printf("Tweet by %s: %s\n", t.User, t.Message)
	}
}
// TotalHits is another convenience function that works even when something goes wrong.
fmt.Printf("Found a total of %d tweets\n", searchResult.TotalHits())

// Here's how you iterate through results with full control over each step.
if searchResult.Hits.TotalHits > 0 {
	fmt.Printf("Found a total of %d tweets\n", searchResult.Hits.TotalHits)

	// Iterate through results
	for _, hit := range searchResult.Hits.Hits {
		// hit.Index contains the name of the index

		// Deserialize hit.Source into a Tweet (could also be just a map[string]interface{}).
		var t Tweet
		err := json.Unmarshal(*hit.Source, &t)
		if err != nil {
			// Deserialization failed
		}

		// Work with tweet
		fmt.Printf("Tweet by %s: %s\n", t.User, t.Message)
	}
} else {
	// No hits
	fmt.Print("Found no tweets\n")
}

// Delete the index again
_, err = client.DeleteIndex("tweets").Do(context.Background())
if err != nil {
	// Handle error
	panic(err)
}

}