Elastic

Elastic is an Elasticsearch client for the Go programming language.

See the wiki for additional information about Elastic.

Releases

The release branches (e.g. release-branch.v3) are actively being worked on and can break at any time. If you want to use stable versions of Elastic, please use the packages released via gopkg.in.

Here's the version matrix:

Elasticsearch version	Elastic version -	Package URL
2.x	3.0	`gopkg.in/olivere/elastic.v3` (source doc)
1.x	2.0	`gopkg.in/olivere/elastic.v2` (source doc)
0.9-1.3	1.0	`gopkg.in/olivere/elastic.v1` (source doc)

Example:

You have installed Elasticsearch 2.1.1 and want to use Elastic. As listed above, you should use Elastic 3.0. So you first install the stable release of Elastic 3.0 from gopkg.in.

$ go get gopkg.in/olivere/elastic.v3

You then import it with this import path:

import "gopkg.in/olivere/elastic.v3"

Elastic 3.0

Elastic 3.0 targets Elasticsearch 2.0 and later. Elasticsearch 2.0.0 was released on 28th October 2015.

Notice that there are a lot of breaking changes in Elasticsearch 2.0 and we used this as an opportunity to clean up and refactor Elastic as well.

Elastic 2.0

Elastic 2.0 targets Elasticsearch 1.x and is published via gopkg.in/olivere/elastic.v2.

Elastic 1.0

Elastic 1.0 is deprecated. You should really update Elasticsearch and Elastic to a recent version.

However, if you cannot update for some reason, don't worry. Version 1.0 is still available. All you need to do is go-get it and change your import path as described above.

Status

We use Elastic in production since 2012. Elastic is stable but the API changes now and then. We strive for API compatibility. However, Elasticsearch sometimes introduces breaking changes and we sometimes have to adapt.

Having said that, there have been no big API changes that required you to rewrite your application big time. More often than not it's renaming APIs and adding/removing features so that Elastic is in sync with Elasticsearch.

Elastic has been used in production with the following Elasticsearch versions: 0.90, 1.0-1.7. Furthermore, we use Travis CI to test Elastic with the most recent versions of Elasticsearch and Go. See the .travis.yml file for the exact matrix and Travis for the results.

Elasticsearch has quite a few features. Most of them are implemented by Elastic. I add features and APIs as required. It's straightforward to implement missing pieces. I'm accepting pull requests :-)

Having said that, I hope you find the project useful.

Getting Started

The first thing you do is to create a Client. The client connects to Elasticsearch on http://127.0.0.1:9200 by default.

You typically create one client for your app. Here's a complete example of creating a client, creating an index, adding a document, executing a search etc.

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

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

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

// Search with a term query
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()                // 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("twitter").Do()
if err != nil {
    // Handle error
    panic(err)
}

Here's a link to a complete working example.

See the wiki for more details.

API Status

Document APIs

Search APIs

Aggregations

Indices APIs

cat APIs

The cat APIs are not implemented as of now. We think they are better suited for operating with Elasticsearch on the command line.

Cluster APIs

Query DSL

Modules

Snapshot and Restore

Sorting

Sort by score
Sort by field
Sort by geo distance
Sort by script

Scan

Scrolling through documents (e.g. search_type=scan) are implemented via the Scroll and Scan services. The ClearScroll API is implemented as well.

How to contribute

Read the contribution guidelines.

Credits

Thanks a lot for the great folks working hard on Elasticsearch and Go.

Elastic uses portions of the uritemplates library by Joshua Tacoma and backoff by Cenk Altı.

LICENSE

MIT-LICENSE. See LICENSE or the LICENSE file provided in the repository for details.

VojtechVitek/elastic