Golang: Data Indexing to Elasticsearch and Elasticsearch Query Builder

This repository provides a program to index customer data into Elasticsearch using the provided query builder and the github.com/elastic/go-elasticsearch/v8 package, along with a query builder utility for constructing Elasticsearch queries in Go.

Prerequisites

Before using the provided code, make sure you have the following prerequisites installed:

• Go programming language (https://golang.org/)
• Elasticsearch server (https://www.elastic.co/guide/en/elasticsearch/reference/current/install-elasticsearch.html)

Installation

To use the provided code, you need to have the necessary packages installed. Use the following commands to install them:

go get github.com/elastic/go-elasticsearch/v8

Customer Data Indexing to Elasticsearch

The provided program demonstrates how to index customer data into Elasticsearch using the query builder and the github.com/elastic/go-elasticsearch/v8 package.

Usage

1. Import necessary packages and define the Customer struct:

import (
    "context"
    "encoding/json"
    "fmt"
    "log"
    "strings"

    "github.com/elastic/go-elasticsearch/v8"
)

// Customer represents customer data
type Customer struct {
    ID          int    `json:"id"`
    FirstName   string `json:"FirstName"`
    LastName    string `json:"LastName"`
    City        string `json:"City"`
    Email       string `json:"Email"`
    PhoneNumber string `json:"PhoneNumber"`
}

2. Create an Elasticsearch client:

esCfg := elasticsearch.Config{
    Addresses: []string{"http://localhost:9200"},
}
esClient, err := elasticsearch.NewClient(esCfg)
if err != nil {
    log.Fatalf("Error creating Elasticsearch client: %s", err)
}

3. Index customer data into Elasticsearch:

indexName := "customer_index" // Replace with your desired index name
for _, customer := range customerData {
    if err := indexCustomer(esClient, indexName, customer); err != nil {
        log.Printf("Error indexing customer %d: %s", customer.ID, err)
    } else {
        log.Printf("Customer %d indexed successfully", customer.ID)
    }
}

4. Replace indexName and the sample customerData with your actual index name and customer data.

Elasticsearch Query Builder

The Elasticsearch query builder package (querybuilder) offers a set of functions to construct custom Elasticsearch queries with specified filters and search conditions.

Usage

1. Import the necessary packages:

import (
    "context"
    "encoding/json"
    "fmt"
    "log"
    "strings"

    "github.com/elastic/go-elasticsearch/v8"
    "your/querybuilder/package/import/path"
)

2. Create an Elasticsearch client:

esCfg := elasticsearch.Config{
    Addresses: []string{"http://localhost:9200"},
}
esClient, err := elasticsearch.NewClient(esCfg)
if err != nil {
    log.Fatalf("Error creating Elasticsearch client: %s", err)
}

3. Build the query using the query builder:

query := querybuilder.CustomerListQuery(0, 10, "John", "", "New York", "", "", "")

4. Convert the query map to JSON:

queryJSON, err := json.Marshal(query)
if err != nil {
    log.Fatalf("Error marshaling query to JSON: %s", err)
}

5. Send the query to Elasticsearch:

res, err := esClient.Search(
    esClient.Search.WithIndex("your_index_name"), // Replace with your actual index name
    esClient.Search.WithBody(strings.NewReader(string(queryJSON))),
)
if err != nil {
    log.Fatalf("Error executing Elasticsearch query: %s", err)
}
defer res.Body.Close()

6. Parse and print the response:

var resMap map[string]interface{}
if err := json.NewDecoder(res.Body).Decode(&resMap); err != nil {
    log.Fatalf("Error decoding response: %s", err)
}
fmt.Println(resMap)

Running the Program

1. Ensure your Elasticsearch server is running.
2. Run the program:

go run main.go

License

This project is licensed under the MIT License.
“`

This template places the customer data indexing section at the beginning, as requested, while also providing clear instructions for both indexing customer data and using the Elasticsearch query builder. Remember to replace placeholders such as "http://localhost:9200", "your/querybuilder/package/import/path", "your_index_name", "customer_index", and the sample customerData with your actual Elasticsearch server address, query builder package import path, index names, and customer data.