implement generate key script in Go (#43)

* implement generate key script in Go

* Update readme

Author: christopherjstock

go/README.md

@@ -24,6 +24,15 @@ This quickstart demonstrates various usages of the the [Algolia Go API Client](h
 
 ## How to use
 
+The module has two dependencies:
+* [Algolia GO API client](github.com/algolia/algoliasearch-client-go/v3)
+* [GoDotEnv](https://github.com/joho/godotenv) - for using environment variables
+
+Install these dependencies using the go build command.
+
+```bash
+go build
+```
 Once setup, you can run each of the script in this folder using the Go command line.
 Example: to execute the `simple.go` script:
 
@@ -37,3 +46,4 @@ go run simple.go
 | ------------- | ------------- |
 | [simple.go](./simple.go)  | Index a single object and run a search query |
 | [indexing.go](./indexing.go)  | Showcase of the main indexing methods |
+| [generate_key.go](./generate_key.go) | Generate a rate limted search API key |

go/generate_key.go

@@ -0,0 +1,75 @@
+// generate_key creates an API key for an Algolia application.
+// The generated key will be valid for Search operations only, and is limited to 100
+// queries per hour.
+
+package main
+
+// Install the API client: https://www.algolia.com/doc/api-client/getting-started/install/go/?client=go
+import (
+	"errors"
+	"fmt"
+	"log"
+	"os"
+
+	"github.com/algolia/algoliasearch-client-go/v3/algolia/search"
+	"github.com/joho/godotenv"
+)
+
+func main() {
+	var err error
+
+	err = godotenv.Load()
+	if err != nil {
+		log.Fatal("Error loading .env file")
+	}
+	// Get your Algolia Application ID and (admin) API key from the dashboard: https://www.algolia.com/account/api-keys
+	// and choose a name for your index. Add these environment variables to a `.env` file:
+	appID, apiKey, indexName := os.Getenv("ALGOLIA_APP_ID"), os.Getenv("ALGOLIA_API_KEY"), os.Getenv("ALGOLIA_INDEX_NAME")
+
+	// Start the API client
+	// https://www.algolia.com/doc/api-client/getting-started/instantiate-client-index/
+	client := search.NewClient(appID, apiKey)
+
+	// Create the API key.
+	// https://www.algolia.com/doc/api-reference/api-methods/add-api-key/?client=go
+	fmt.Println("Generating key...")
+
+	keyParams := search.Key{
+		ACL:                    []string{"search"},
+		Description:            "Restricted search-only API key for algolia.com",
+		MaxQueriesPerIPPerHour: 100,
+	}
+
+	var key string
+	var keyRes search.CreateKeyRes
+
+	keyRes, err = client.AddAPIKey(keyParams)
+	err = keyRes.Wait()
+	if err != nil {
+		panic(errors.New("Error generating key."))
+	} else {
+		key = keyRes.Key
+		fmt.Println("Key generated successfully:", key)
+	}
+
+	// Test the new key
+	fmt.Println("Testing key...")
+
+	// Initialise a new client with the generated key
+	client = search.NewClient(appID, key)
+
+	// Create an index (or connect to it, if an index with the name `ALGOLIA_INDEX_NAME` already exists)
+	// https://www.algolia.com/doc/api-client/getting-started/instantiate-client-index/#initialize-an-index
+	index := client.InitIndex(indexName)
+
+	// Search the index with an empty string
+	// https://www.algolia.com/doc/api-reference/api-methods/search/
+	var indexRes search.QueryRes
+
+	indexRes, err = index.Search("")
+	if err != nil {
+		panic(errors.New("Error testing key."))
+	} else {
+		fmt.Println("Key tested successfully.", indexRes.NbHits, "hits found.")
+	}
+}