Search

The Search service allows to search for documents. There are many types of queries, filters, facets, aggregations etc. you can use here.

Iterating through the search results can be either done with full control or with Each, a convenience function.

// Search with a term query
ctx := context.Background()
termQuery := elastic.NewTermQuery("user", "olivere")
searchResult, err := client.Search().
    Index("twitter").   // search in index "twitter"
    Query(termQuery).   // specify the query
    Sort("user", true). // sort by "user" field, ascending
    From(0).Size(10).   // take documents 0-9
    Pretty(true).       // pretty print request and response JSON
    Do(ctx)             // 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 the process, see below.
var ttyp Tweet
for _, item := range searchResult.Each(reflect.TypeOf(ttyp)) {
    t := item.(Tweet)
    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 the search results with full control over each step.
if searchResult.Hits.TotalHits.Value > 0 {
    fmt.Printf("Found a total of %d tweets\n", searchResult.Hits.TotalHits.Value)

    // 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")
}