Elastigo - Elasticsearch Go 客户端库使用指南

elastigo 是一个 Go 语言的 Elasticsearch 客户端库，提供了与 Elasticsearch 交互的简单接口。虽然官方现在推荐使用 olivere/elastic，但 elastigo 仍然是一个轻量级的选择。

安装

go get github.com/mattbaird/elastigo/lib

基本使用

1. 初始化连接

package main

import (
	"fmt"
	"github.com/mattbaird/elastigo/lib"
)

func main() {
	// 创建连接器
	conn := lib.NewConn()
	
	// 设置Elasticsearch服务器地址
	conn.Domain = "localhost"
	conn.Port = "9200"
	
	// 测试连接
	_, err := conn.Health()
	if err != nil {
		panic(err)
	}
	fmt.Println("Connected to Elasticsearch")
}

2. 创建索引

func createIndex(conn *lib.Conn) {
	// 创建索引
	_, err := conn.CreateIndex("myindex")
	if err != nil {
		fmt.Printf("Error creating index: %v\n", err)
	} else {
		fmt.Println("Index created successfully")
	}
	
	// 可选：设置映射
	mapping := `{
		"settings": {
			"number_of_shards": 1,
			"number_of_replicas": 0
		},
		"mappings": {
			"properties": {
				"title": {"type": "text"},
				"content": {"type": "text"},
				"timestamp": {"type": "date"}
			}
		}
	}`
	
	_, err = conn.DoCommand("PUT", "/myindex", nil, mapping)
	if err != nil {
		fmt.Printf("Error setting mapping: %v\n", err)
	}
}

3. 索引文档

func indexDocument(conn *lib.Conn) {
	doc := map[string]interface{}{
		"title":     "Elastigo Example",
		"content":   "This is an example document for elastigo",
		"timestamp": "2023-01-01T00:00:00Z",
	}
	
	_, err := conn.Index("myindex", "mytype", "1", nil, doc)
	if err != nil {
		fmt.Printf("Error indexing document: %v\n", err)
	} else {
		fmt.Println("Document indexed successfully")
	}
}

4. 搜索文档

func searchDocuments(conn *lib.Conn) {
	query := `{
		"query": {
			"match": {
				"content": "example"
			}
		}
	}`
	
	out, err := conn.Search("myindex", "mytype", nil, query)
	if err != nil {
		fmt.Printf("Error searching: %v\n", err)
		return
	}
	
	fmt.Printf("Found %d hits\n", out.Hits.Total)
	for _, hit := range out.Hits.Hits {
		fmt.Printf("ID: %s, Source: %v\n", hit.Id, hit.Source)
	}
}

5. 更新文档

func updateDocument(conn *lib.Conn) {
	update := map[string]interface{}{
		"doc": map[string]interface{}{
			"content": "Updated content for elastigo example",
		},
	}
	
	_, err := conn.Update("myindex", "mytype", "1", nil, update)
	if err != nil {
		fmt.Printf("Error updating document: %v\n", err)
	} else {
		fmt.Println("Document updated successfully")
	}
}

6. 删除文档和索引

func deleteOperations(conn *lib.Conn) {
	// 删除文档
	_, err := conn.Delete("myindex", "mytype", "1", nil)
	if err != nil {
		fmt.Printf("Error deleting document: %v\n", err)
	} else {
		fmt.Println("Document deleted successfully")
	}
	
	// 删除索引
	_, err = conn.DeleteIndex("myindex")
	if err != nil {
		fmt.Printf("Error deleting index: %v\n", err)
	} else {
		fmt.Println("Index deleted successfully")
	}
}

高级功能

批量操作

func bulkOperations(conn *lib.Conn) {
	bulk := conn.NewBulkIndexRequest()
	
	// 添加多个索引操作
	doc1 := map[string]interface{}{"title": "Bulk Doc 1", "content": "Content 1"}
	doc2 := map[string]interface{}{"title": "Bulk Doc 2", "content": "Content 2"}
	
	bulk.Add("myindex", "mytype", "2", nil, doc1)
	bulk.Add("myindex", "mytype", "3", nil, doc2)
	
	// 执行批量操作
	_, err := bulk.Do()
	if err != nil {
		fmt.Printf("Error in bulk operation: %v\n", err)
	} else {
		fmt.Println("Bulk operations completed successfully")
	}
}

使用过滤器

func filteredSearch(conn *lib.Conn) {
	query := `{
		"query": {
			"bool": {
				"must": {
					"match": {"content": "example"}
				},
				"filter": {
					"range": {
						"timestamp": {
							"gte": "2022-01-01",
							"lte": "2023-12-31"
						}
					}
				}
			}
		}
	}`
	
	out, err := conn.Search("myindex", "mytype", nil, query)
	if err != nil {
		fmt.Printf("Error in filtered search: %v\n", err)
		return
	}
	
	fmt.Printf("Filtered search found %d hits\n", out.Hits.Total)
}

注意事项

1. elastigo 已经不再积极维护，对于新项目建议考虑官方推荐的客户端
2. 生产环境中应该处理连接池和错误重试
3. 对于复杂查询，建议使用结构体而不是原始JSON字符串
4. 记得在完成操作后关闭连接

elastigo 提供了基本的 Elasticsearch 操作接口，适合简单的用例。对于更复杂的场景，可能需要考虑功能更全面的客户端库。