Perform sentiment analysis by using the gcloud tool

This page shows you how to get started with the Cloud Natural Language API using the Google Cloud SDK.


For step-by-step guidance on this task directly in Cloud console, click Guide me:

Guide me


The following sections take you through the same steps as clicking Guide me.

Before you begin

  1. Sign in to your Google Cloud account. If you're new to Google Cloud, create an account to evaluate how our products perform in real-world scenarios. New customers also get $300 in free credits to run, test, and deploy workloads.
  2. In the Google Cloud console, on the project selector page, select or create a Google Cloud project.

    Go to project selector

  3. Make sure that billing is enabled for your Cloud project. Learn how to check if billing is enabled on a project.

  4. Enable the Cloud Natural Language API.

    Enable the API

  5. Create a service account:

    1. In the Cloud console, go to the Create service account page.

      Go to Create service account
    2. Select your project.
    3. In the Service account name field, enter a name. The Cloud console fills in the Service account ID field based on this name.

      In the Service account description field, enter a description. For example, Service account for quickstart.

    4. Click Create and continue.
    5. Click Done to finish creating the service account.

      Do not close your browser window. You will use it in the next step.

  6. Create a service account key:

    1. In the Cloud console, click the email address for the service account that you created.
    2. Click Keys.
    3. Click Add key, and then click Create new key.
    4. Click Create. A JSON key file is downloaded to your computer.
    5. Click Close.
  7. Set the environment variable GOOGLE_APPLICATION_CREDENTIALS to the path of the JSON file that contains your service account key. This variable only applies to your current shell session, so if you open a new session, set the variable again.

  8. Install and initialize the Google Cloud CLI.
  9. In the Google Cloud console, on the project selector page, select or create a Google Cloud project.

    Go to project selector

  10. Make sure that billing is enabled for your Cloud project. Learn how to check if billing is enabled on a project.

  11. Enable the Cloud Natural Language API.

    Enable the API

  12. Create a service account:

    1. In the Cloud console, go to the Create service account page.

      Go to Create service account
    2. Select your project.
    3. In the Service account name field, enter a name. The Cloud console fills in the Service account ID field based on this name.

      In the Service account description field, enter a description. For example, Service account for quickstart.

    4. Click Create and continue.
    5. Click Done to finish creating the service account.

      Do not close your browser window. You will use it in the next step.

  13. Create a service account key:

    1. In the Cloud console, click the email address for the service account that you created.
    2. Click Keys.
    3. Click Add key, and then click Create new key.
    4. Click Create. A JSON key file is downloaded to your computer.
    5. Click Close.
  14. Set the environment variable GOOGLE_APPLICATION_CREDENTIALS to the path of the JSON file that contains your service account key. This variable only applies to your current shell session, so if you open a new session, set the variable again.

  15. Install and initialize the Google Cloud CLI.

Make an entity analysis request

gcloud

Use the gcloud command line tool to call the analyze-entities command and use the --content flag to specify the text to analyze.
gcloud ml language analyze-entities --content="Michelangelo Caravaggio, Italian painter, is known for 'The Calling of Saint Matthew'."

Command-line

Use curl to make a POST request to the documents:analyzeEntities method and provide the appropriate request body as shown in the following example.

The example uses the gcloud auth application-default print-access-token command to obtain an access token for the service account that you created when you set up the project.

curl -X POST \
  -H "Authorization: Bearer "$(gcloud auth application-default print-access-token) \
  -H "Content-Type: application/json; charset=utf-8" \
 "https://language.googleapis.com/v1/documents:analyzeEntities" \
  --data "{
  'document':{
    'type':'PLAIN_TEXT',
    'content':'Michelangelo Caravaggio, Italian painter, is known for
              \'The Calling of Saint Matthew\'.'
  },
  'encodingType':'UTF8'
}"

You should see a response similar to the following:

{
  "entities": [
    {
      "name": "Michelangelo Caravaggio",
      "type": "PERSON",
      "metadata": {
        "wikipedia_url": "http://en.wikipedia.org/wiki/Caravaggio",
        "mid": "/m/020bg"
      },
      "salience": 0.83047235,
      "mentions": [
        {
          "text": {
            "content": "Michelangelo Caravaggio",
            "beginOffset": 0
          },
          "type": "PROPER"
        },
        {
          "text": {
            "content": "painter",
            "beginOffset": 33
          },
          "type": "COMMON"
        }
      ]
    },
    {
      "name": "Italian",
      "type": "LOCATION",
      "metadata": {
        "mid": "/m/03rjj",
        "wikipedia_url": "http://en.wikipedia.org/wiki/Italy"
      },
      "salience": 0.13870546,
      "mentions": [
        {
          "text": {
            "content": "Italian",
            "beginOffset": 25
          },
          "type": "PROPER"
        }
      ]
    },
    {
      "name": "The Calling of Saint Matthew",
      "type": "EVENT",
      "metadata": {
        "mid": "/m/085_p7",
        "wikipedia_url": "http://en.wikipedia.org/wiki/The_Calling_of_St_Matthew_(Caravaggio)"
      },
      "salience": 0.030822212,
      "mentions": [
        {
          "text": {
            "content": "The Calling of Saint Matthew",
            "beginOffset": 69
          },
          "type": "PROPER"
        }
      ]
    }
  ],
  "language": "en"
}

Clean up

  1. In the Cloud console, go to the Manage resources page.

    Go to Manage resources

  2. In the project list, select the project that you want to delete, and then click Delete.
  3. In the dialog, type the project ID, and then click Shut down to delete the project.

What's next