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Python client library for IBM Cloudant

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IBM Cloudant Python SDK Version 0.1.3

IBM Cloudant Python SDK is a client library that interacts with the IBM Cloudant APIs.

Disclaimer: This library is still a 0.x release. We do consider this library production-ready and capable, but there are still some limitations we’re working to resolve, and refinements we want to deliver. We are working really hard to minimise the disruption from now until the 1.0 release, but there may still be some changes that impact applications using this SDK. For now, be sure to pin versions to avoid surprises.

Table of Contents

Overview

The IBM Cloudant Python SDK allows developers to programmatically interact with IBM Cloudant with the help of the ibmcloudant package.

Features

The purpose of this Python SDK is to wrap most of the HTTP request APIs provided by Cloudant and supply other functions to ease the usage of Cloudant. This SDK should make life easier for programmers to do what’s really important to them: developing software.

Reasons why you should consider using Cloudant Python SDK in your project:

  • Supported by IBM Cloudant.
  • Server compatibility with:
  • Includes all the most popular and latest supported endpoints for applications.
  • Handles the authentication.
  • Familiar user experience with IBM Cloud SDKs.
  • Flexibility to use either built-in models or byte-based requests and responses for documents.
  • Instances of the client are unconditionally thread-safe.

Prerequisites

Installation

To install, use pip or easy_install:

pip install --upgrade "ibmcloudant>=0.1.3"

or

easy_install --upgrade "ibmcloudant>=0.1.3"

Authentication

This library requires some of your Cloudant service credentials to authenticate with your account.

  1. IAM, COUCHDB_SESSION, BASIC or NOAUTH authentication type.
    1. IAM authentication is highly recommended when your back-end database server is Cloudant. This authentication type requires a server-generated apikey instead of a user-given password. You can create one here.
    2. Session cookie (COUCHDB_SESSION) authentication is recommended for Apache CouchDB or for Cloudant when IAM is unavailable. It exchanges username and password credentials for an AuthSession cookie from the /_session endpoint.
    3. Basic (or legacy) authentication is a fallback for both Cloudant and Apache CouchDB back-end database servers. This authentication type requires the good old username and password credentials.
    4. Noauth authentication does not require credentials. Note that this authentication type only works with queries against a database with read access for everyone.
  2. The service url.

There are several ways to set these properties:

  1. As environment variables
  2. The programmatic approach
  3. With an external credentials file

Authentication with environment variables

IAM authentication

For Cloudant IAM authentication, set the following environmental variables by replacing the <url> and <apikey> with your proper service credentials. There is no need to set CLOUDANT_AUTH_TYPE to IAM because it is the default.

CLOUDANT_URL=<url>
CLOUDANT_APIKEY=<apikey>

Session cookie authentication

For COUCHDB_SESSION authentication, set the following environmental variables by replacing the <url>, <username> and <password> with your proper service credentials.

CLOUDANT_AUTH_TYPE=COUCHDB_SESSION
CLOUDANT_URL=<url>
CLOUDANT_USERNAME=<username>
CLOUDANT_PASSWORD=<password>

Basic authentication

For Basic authentication, set the following environmental variables by replacing the <url>, <username> and <password> with your proper service credentials.

CLOUDANT_AUTH_TYPE=BASIC
CLOUDANT_URL=<url>
CLOUDANT_USERNAME=<username>
CLOUDANT_PASSWORD=<password>

Note: We recommend that you use IAM for Cloudant and Session for CouchDB authentication.

Authentication with external configuration

To use an external configuration file, the Cloudant API docs, or the general SDK usage information will guide you.

Programmatic authentication

To learn more about how to use programmatic authentication, see the related documentation in the Cloudant API docs or in the Python SDK Core document about authentication.

Using the SDK

For fundamental SDK usage information and config options, please see the common IBM Cloud SDK documentation.

Request timeout configuration

No request timeout is defined, but a 2.5m read and a 60s connect timeout are set by default. Be sure to set a request timeout appropriate to your application usage and environment. The request timeout section contains details on how to change the value.

Note: System settings may take precedence over configured timeout values.

Code examples

The following code examples authenticate with the environment variables.

1. Retrieve information from an existing database

Note: This example code assumes that animaldb database does not exist in your account.

This example code gathers information about an existing database hosted on the https://examples.cloudant.com/ service url. To connect, you must extend your environment variables with the service url and authentication type to use NOAUTH authentication while you connect to the animaldb database. This step is necessary for the SDK to distinguish the EXAMPLES custom service name from the default service name which is CLOUDANT.

Cloudant environment variable naming starts with a service name prefix that identifies your service. By default this is CLOUDANT, see the settings in the authentication with environment variables section.

If you would like to rename your Cloudant service from CLOUDANT, you must use your defined service name as the prefix for all Cloudant related environment variables. The code block below provides an example of instantiating a user-defined EXAMPLES service name.

EXAMPLES_URL=https://examples.cloudant.com
EXAMPLES_AUTH_TYPE=NOAUTH

Once the environment variables are set, you can try out the code examples.

import json

from ibmcloudant.cloudant_v1 import CloudantV1

# 1. Create a Cloudant client with "EXAMPLES" service name ============
client = CloudantV1.new_instance(service_name="EXAMPLES")

# 2. Get server information ===========================================
server_information = client.get_server_information(
).get_result()

print(f'Server Version: {server_information["version"]}')

# 3. Get database information for "animaldb" ==========================
db_name = "animaldb"

db_information = client.get_database_information(
    db=db_name
).get_result()

# 4. Show document count in database ==================================
document_count = db_information["doc_count"]

print(f'Document count in \"{db_information["db_name"]}\" '
      f'database is {document_count}.')

# 5. Get zebra document out of the database by document id ============
document_about_zebra = client.get_document(
    db=db_name,
    doc_id="zebra"
).get_result()

print(f'Document retrieved from database:\n'
      f'{json.dumps(document_about_zebra, indent=2)}')

When you run the code, you see a result similar to the following output.

Server Version: 2.1.1
Document count in "animaldb" database is 11.
Document retrieved from database:
{
  "_id": "zebra",
  "_rev": "3-750dac460a6cc41e6999f8943b8e603e",
  "wiki_page": "http://en.wikipedia.org/wiki/Plains_zebra",
  "min_length": 2,
  "max_length": 2.5,
  "min_weight": 175,
  "max_weight": 387,
  "class": "mammal",
  "diet": "herbivore"
}

2. Create your own database and add a document

Note: This example code assumes that orders database does not exist in your account.

Now comes the exciting part, you create your own orders database and add a document about Bob Smith with your own IAM or Basic service credentials.

Create code example
import logging

from ibm_cloud_sdk_core import ApiException
from ibmcloudant.cloudant_v1 import CloudantV1, Document

# Set logging level to show only critical logs
logging.basicConfig(level=logging.CRITICAL)

# 1. Create a client with `CLOUDANT` default service name =============
client = CloudantV1.new_instance()

# 2. Create a database ================================================
example_db_name = "orders"

# Try to create database if it doesn't exist
try:
    put_database_result = client.put_database(
        db=example_db_name
    ).get_result()
    if put_database_result["ok"]:
        print(f'"{example_db_name}" database created.')
except ApiException as ae:
    if ae.code == 412:
        print(f'Cannot create "{example_db_name}" database, ' +
              'it already exists.')

# 3. Create a document ================================================
# Create a document object with "example" id
example_doc_id = "example"
# Setting `id` for the document is optional when "post_document"
# function is used for CREATE. When `id` is not provided the server
# will generate one for your document.
example_document: Document = Document(id=example_doc_id)

# Add "name" and "joined" fields to the document
example_document.name = "Bob Smith"
example_document.joined = "2019-01-24T10:42:59.000Z"

# Save the document in the database with "post_document" function
create_document_response = client.post_document(
    db=example_db_name,
    document=example_document
).get_result()

# =====================================================================
# Note: saving the document can also be done with the "put_document"
# function. In this case `doc_id` is required for a CREATE operation:
"""
create_document_response = client.put_document(
    db=example_db_name,
    doc_id=example_doc_id,
    document=example_document
).get_result()
"""
# =====================================================================

# Keeping track of the revision number of the document object
# is necessary for further UPDATE/DELETE operations:
example_document.rev = create_document_response["rev"]
print(f'You have created the document:\n{example_document}')
When you run the code, you see a result similar to the following output.
"orders" database created.
You have created the document:
{
  "_id": "example",
  "_rev": "1-1b403633540686aa32d013fda9041a5d",
  "name": "Bob Smith",
  "joined": "2019-01-24T10:42:99.000Z"
}

3. Update your previously created document

Note: This example code assumes that you have created both the orders database and the example document by running the previous example code successfully. Otherwise, the following error message occurs, "Cannot update document because either 'orders' database or 'example' document was not found."

Update code example
import json
import logging

from ibm_cloud_sdk_core import ApiException
from ibmcloudant.cloudant_v1 import CloudantV1

# Set logging level to show only critical logs
logging.basicConfig(level=logging.CRITICAL)

# 1. Create a client with `CLOUDANT` default service name =============
client = CloudantV1.new_instance()

# 2. Update the document ==============================================
example_db_name = "orders"
example_doc_id = "example"

# Try to get the document if it previously existed in the database
try:
    document = client.get_document(
        db=example_db_name,
        doc_id=example_doc_id
    ).get_result()

    # =================================================================
    # Note: for response byte stream use:
    """
    document_as_byte_stream = client.get_document_as_stream(
        db=example_db_name,
        doc_id=example_doc_id
    ).get_result()
    """
    # =================================================================

    #  Add Bob Smith's address to the document
    document["address"] = "19 Front Street, Darlington, DL5 1TY"

    #  Remove the joined property from document object
    if "joined" in document:
        document.pop("joined")

    # Update the document in the database
    update_document_response = client.post_document(
        db=example_db_name,
        document=document
    ).get_result()

    # =================================================================
    # Note 1: for request byte stream use:
    """
    update_document_response = client.post_document(
        db=example_db_name,
        document=document_as_byte_stream
    ).get_result()
    """
    # =================================================================

    # =================================================================
    # Note 2: updating the document can also be done with the
    # "put_document" function. `doc_id` and `rev` are required for an
    # UPDATE operation, but `rev` can be provided in the document
    # object as `_rev` too:
    """
    update_document_response = client.put_document(
        db=example_db_name,
        doc_id=example_doc_id,  # doc_id is a required parameter
        rev=document["_rev"],
        document=document  # _rev in the document object CAN replace above `rev` parameter
    ).get_result()
    """
    # =================================================================

    # Keeping track of the latest revision number of the document
    # object is necessary for further UPDATE/DELETE operations:
    document["_rev"] = update_document_response["rev"]
    print(f'You have updated the document:\n' +
          json.dumps(document, indent=2))

except ApiException as ae:
    if ae.code == 404:
        print('Cannot delete document because either ' +
              f'"{example_db_name}" database or "{example_doc_id}" ' +
              'document was not found.')
When you run the code, you see a result similar to the following output.
{
  "_id": "example",
  "_rev": "2-4e2178e85cffb32d38ba4e451f6ca376",
  "name": "Bob Smith",
  "address": "19 Front Street, Darlington, DL5 1TY"
}

4. Delete your previously created document

Note: This example code assumes that you have created both the orders database and the example document by running the previous example code successfully. Otherwise, the following error message occurs, "Cannot delete document because either 'orders' database or 'example' document was not found."

Delete code example
import logging

from ibm_cloud_sdk_core import ApiException
from ibmcloudant.cloudant_v1 import CloudantV1

# Set logging level to show only critical logs
logging.basicConfig(level=logging.CRITICAL)

# 1. Create a client with `CLOUDANT` default service name =============
client = CloudantV1.new_instance()

# 2. Delete the document ==============================================
example_db_name = "orders"
example_doc_id = "example"

# Try to get the document if it previously existed in the database
try:
    document = client.get_document(
        db=example_db_name,
        doc_id=example_doc_id
    ).get_result()

    delete_document_response = client.delete_document(
        db=example_db_name,
        doc_id=example_doc_id,  # `doc_id` is required for DELETE
        rev=document["_rev"]    # `rev` is required for DELETE
    ).get_result()

    if delete_document_response["ok"]:
        print('You have deleted the document.')

except ApiException as ae:
    if ae.code == 404:
        print('Cannot delete document because either ' +
              f'"{example_db_name}" database or "{example_doc_id}"' +
              'document was not found.')
When you run the code, you see the following output.
You have deleted the document.

Further code examples

For a complete list of code examples, see the examples directory.

Error handling

For sample code on handling errors, see Cloudant API docs.

Raw IO

For endpoints that read or write document content it is possible to bypass usage of the built-in object with byte streams.

Depending on the specific SDK operation it may be possible to:

  • accept a user-provided byte stream to send to the server as a request body
  • return a byte stream of the server response body to the user

Request byte stream can be supplied for arguments that accept the BinaryIO type. For these cases you can pass this byte stream directly to the HTTP request body.

Response byte stream is supported in functions with the suffix of _as_stream. The returned byte stream allows the response body to be consumed without triggering JSON unmarshalling that is typically performed by the SDK.

The update document section contains examples for both request and response byte stream cases.

The API reference contains further examples of using byte streams. They are titled "Example request as stream" and are initially collapsed. Expand them to see examples of:

Model classes vs dictionaries

This SDK supports two possible formats to define an HTTP request. One approach uses only model classes and the other only dictionaries.

Example using model class structure
from ibmcloudant.cloudant_v1 import DesignDocument, CloudantV1, DesignDocumentOptions, SearchIndexDefinition

client = CloudantV1.new_instance()

price_index = SearchIndexDefinition(
    index='function (doc) { index("price", doc.price); }'
)

design_document_options = DesignDocumentOptions(
    partitioned=True
)

partitioned_design_doc = DesignDocument(
    indexes={'findByPrice': price_index},
    options=design_document_options
)

response = client.put_design_document(
    db='products',
    design_document=partitioned_design_doc,
    ddoc='appliances'
).get_result()

print(response)
Same example using dictionary structure
from ibmcloudant.cloudant_v1 import CloudantV1

client = CloudantV1.new_instance()

price_index = {
    'index': 'function (doc) { index("price", doc.price); }'
}

partitioned_design_doc = {
    'indexes': {'findByPrice': price_index},
    'options': {'partitioned': True},
}

response = client.put_design_document(
    db='products',
    design_document=partitioned_design_doc,
    ddoc='appliances'
).get_result()

print(response)

Since model classes and dicts are different data structures, they cannot be combined.

This solution will be invalid
from ibmcloudant.cloudant_v1 import CloudantV1, DesignDocument

client = CloudantV1.new_instance()

price_index = {
    'index': 'function (doc) { index("price", doc.price); }'
}

partitioned_design_doc = DesignDocument(
    indexes={'findByPrice': price_index},
    options={'partitioned': True}
)

response = client.put_design_document(
    db='products',
    design_document=partitioned_design_doc,
    ddoc='appliances'
).get_result()

print(response)

Further resources

  • Cloudant API docs: API reference including usage examples for Cloudant Python SDK API.
  • Pydoc: Cloudant Python SDK API Documentation.
  • Cloudant docs: The official documentation page for Cloudant.
  • Cloudant blog: Many useful articles about how to optimize Cloudant for common problems.

Questions

If you are having difficulties using this SDK or have a question about the IBM Cloud services, ask a question on Stack Overflow.

Issues

If you encounter an issue with the project, you are welcome to submit a bug report. Before you submit a bug report, search for similar issues and review the KNOWN_ISSUES file to verify that your issue hasn't been reported yet.

Open source at IBM

Find more open source projects on the IBM Github page.

Contributing

For more information, see CONTRIBUTING.

License

This SDK is released under the Apache 2.0 license. To read the full text of the license, see LICENSE.

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