Indexing a document (POST/PUT) in Elasticsearch - Mini Project: Build & Apply

Indexing a Document in Elasticsearch

📖 Scenario: You work at a company that stores product information in Elasticsearch. You need to add new products to the Elasticsearch index so they can be searched later.

🎯 Goal: Learn how to index a document in Elasticsearch using the POST and PUT methods.

📋 What You'll Learn

Create a JSON document representing a product with specific fields

Set the index name in a variable

Use the POST method to add a new product document without specifying an ID

Use the PUT method to add a product document with a specific ID

Print the JSON response from Elasticsearch

💡 Why This Matters

🌍 Real World

Indexing documents is how search engines like Elasticsearch store data so users can find it quickly.

💼 Career

Knowing how to add and update documents in Elasticsearch is essential for backend developers and data engineers working with search and analytics.

1

Create the product document

Create a JSON object called product with these exact fields and values: "name": "Wireless Mouse", "price": 25.99, "in_stock": true.

Elasticsearch

# Create the product JSON object
# Your code here

Hint

Use Python dictionary syntax to create the product object.

2

Set the index name

Create a variable called index_name and set it to the string "products".

Elasticsearch

product = {
    "name": "Wireless Mouse",
    "price": 25.99,
    "in_stock": True
}

# Set the index name
# Your code here

Hint

Assign the string "products" to the variable index_name.

3

Index the product using POST

Use the requests library to send a POST request to http://localhost:9200/{index_name}/_doc with the product JSON as the body. Store the response in a variable called response_post. Use json=product in the request.

Elasticsearch

import requests

product = {
    "name": "Wireless Mouse",
    "price": 25.99,
    "in_stock": True
}

index_name = "products"

# Send POST request to index the product
# Your code here

Hint

Use requests.post with the URL and json=product to send the data.

4

Index the product using PUT with ID and print response

Send a PUT request to http://localhost:9200/{index_name}/_doc/1001 with the product JSON as the body. Store the response in response_put. Then print the JSON response from response_put using print(response_put.json()).

Elasticsearch

import requests

product = {
    "name": "Wireless Mouse",
    "price": 25.99,
    "in_stock": True
}

index_name = "products"

response_post = requests.post(f"http://localhost:9200/{index_name}/_doc", json=product)

# Send PUT request with ID 1001 and print the response JSON
# Your code here

Hint

Use requests.put with the URL including 1001 as the document ID. Then print the JSON response.

Practice

1. What is the main difference between using POST and PUT when indexing a document in Elasticsearch?

easy

A. POST adds a document with an auto-generated ID, PUT adds or replaces a document with a specified ID.

B. POST deletes a document, PUT updates a document.

C. POST is used only for searching, PUT is used for indexing.

D. POST requires an ID, PUT never requires an ID.

Solution

1. Step 1: Understand POST behavior

   POST indexes a document and Elasticsearch generates a unique ID automatically.

2. Step 2: Understand PUT behavior

   PUT indexes a document with the ID you specify, replacing any existing document with that ID.

3. Final Answer:

   POST adds a document with an auto-generated ID, PUT adds or replaces a document with a specified ID. -> Option A

4. Quick Check:

   Method difference = auto ID vs specified ID [OK]

Hint: Remember: POST auto-IDs, PUT needs your ID [OK]

Common Mistakes:

• Thinking POST deletes documents
• Confusing PUT with search operation
• Assuming PUT never requires an ID

2. Which of the following is the correct syntax to index a document with ID "123" using PUT in Elasticsearch?

easy

A. POST /index/_doc {"field": "value"}

B. POST /index/_doc/123 {"field": "value"}

C. PUT /index/_doc {"field": "value"}

D. PUT /index/_doc/123 {"field": "value"}

Solution

1. Step 1: Identify correct HTTP method and URL

   To specify an ID, use PUT with the URL including the ID: /index/_doc/123.

2. Step 2: Confirm request body format

   The body contains the document fields as JSON, e.g., {"field": "value"}.

3. Final Answer:

   PUT /index/_doc/123 {"field": "value"} -> Option D

4. Quick Check:

   PUT + ID in URL = correct syntax [OK]

Hint: PUT with ID in URL, POST without ID [OK]

Common Mistakes:

• Using POST with an ID in URL
• Omitting the ID when using PUT
• Confusing URL structure

3. Given this request to index a document:

POST /products/_doc
{
  "name": "Coffee Mug",
  "price": 12.99
}

What will Elasticsearch do after this request?

medium

A. Index the document with an auto-generated ID under the 'products' index.

B. Replace any existing document with ID 'products'.

C. Return an error because ID is missing.

D. Create a new index named '_doc'.

Solution

1. Step 1: Analyze the HTTP method and URL

   The request uses POST on /products/_doc, which means index 'products' and type '_doc'.

2. Step 2: Understand ID assignment

   Since no ID is specified, Elasticsearch generates a unique ID automatically and indexes the document.

3. Final Answer:

   Index the document with an auto-generated ID under the 'products' index. -> Option A

4. Quick Check:

   POST without ID = auto-generated ID [OK]

Hint: POST without ID means auto ID assigned [OK]

Common Mistakes:

• Thinking missing ID causes error
• Assuming document replaces existing one
• Confusing index and type names

4. You tried to index a document with PUT /myindex/_doc without specifying an ID. What is the problem with this request?

medium

A. It will create a document with a random ID.

B. It will update all documents in the index.

C. It will cause a syntax error because ID is missing in the URL.

D. It will delete the entire index.

Solution

1. Step 1: Check the HTTP method and URL requirements

   PUT requires an explicit document ID in the URL to index or replace a document.

2. Step 2: Identify the error cause

   Since the ID is missing, Elasticsearch will reject the request with an error due to invalid URL syntax.

3. Final Answer:

   It will cause a syntax error because ID is missing in the URL. -> Option C

4. Quick Check:

   PUT needs ID in URL [OK]

Hint: PUT without ID in URL causes error [OK]

Common Mistakes:

• Assuming PUT auto-generates ID
• Thinking it deletes index
• Believing it updates all documents

5. You want to update a document if it exists or create it if it doesn't, using ID "789" in index "users". Which is the best way to do this in Elasticsearch?

hard

A. Use POST /users/_doc with the document body {"id": "789"}.

B. Use PUT /users/_doc/789 with the document body.

C. Use POST /users/_doc without ID.

D. Use DELETE /users/_doc/789 then POST /users/_doc.

Solution

1. Step 1: Understand update or create behavior

   PUT with a specified ID will create the document if missing or replace it if it exists.

2. Step 2: Compare options

   POST without ID creates new documents with auto IDs, so it won't update by ID. Deleting then posting is inefficient.

3. Final Answer:

   Use PUT /users/_doc/789 with the document body. -> Option B

4. Quick Check:

   PUT with ID updates or creates [OK]

Hint: PUT with ID updates or creates document [OK]

Common Mistakes:

• Specifying ID in the document body
• Omitting ID when update needed
• Deleting before posting wastes resources