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.

To follow step-by-step guidance for this task directly in the Google Cloud console, click Guide me:

Guide me

Before you begin

  1. Sign in to your Google Account.

    If you don't already have one, sign up for a new account.

  2. Install the Google Cloud CLI.

  3. If you're using an external identity provider (IdP), you must first sign in to the gcloud CLI with your federated identity.

  4. To initialize the gcloud CLI, run the following command: 

    gcloud init

  5. Create or select a Google Cloud project.

    Roles required to select or create a project

    • Select a project: Selecting a project doesn't require a specific IAM role—you can select any project that you've been granted a role on.
    • Create a project: To create a project, you need the Project Creator (roles/resourcemanager.projectCreator), which contains the resourcemanager.projects.create permission. Learn how to grant roles.

    • Create a Google Cloud project:

      gcloud projects create PROJECT_ID

      Replace PROJECT_ID with a name for the Google Cloud project you are creating.

    • Select the Google Cloud project that you created:

      gcloud config set project PROJECT_ID

      Replace PROJECT_ID with your Google Cloud project name.

  6. Verify that billing is enabled for your Google Cloud project.

  7. Enable the Cloud Natural Language API:

    Roles required to enable APIs

    To enable APIs, you need the Service Usage Admin IAM role (roles/serviceusage.serviceUsageAdmin), which contains the serviceusage.services.enable permission. Learn how to grant roles. 

    gcloud services enable language.googleapis.com

  8. Install the Google Cloud CLI.

  9. If you're using an external identity provider (IdP), you must first sign in to the gcloud CLI with your federated identity.

  10. To initialize the gcloud CLI, run the following command: 

    gcloud init

  11. Create or select a Google Cloud project.

    Roles required to select or create a project

    • Select a project: Selecting a project doesn't require a specific IAM role—you can select any project that you've been granted a role on.
    • Create a project: To create a project, you need the Project Creator (roles/resourcemanager.projectCreator), which contains the resourcemanager.projects.create permission. Learn how to grant roles.

    • Create a Google Cloud project:

      gcloud projects create PROJECT_ID

      Replace PROJECT_ID with a name for the Google Cloud project you are creating.

    • Select the Google Cloud project that you created:

      gcloud config set project PROJECT_ID

      Replace PROJECT_ID with your Google Cloud project name.

  12. Verify that billing is enabled for your Google Cloud project.

  13. Enable the Cloud Natural Language API:

    Roles required to enable APIs

    To enable APIs, you need the Service Usage Admin IAM role (roles/serviceusage.serviceUsageAdmin), which contains the serviceusage.services.enable permission. Learn how to grant roles. 

    gcloud services enable language.googleapis.com

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

    Delete a Google Cloud project:

    gcloud projects delete PROJECT_ID

What's next