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Global variables

Global variables let you store and reuse generic input values and credentials across your projects. You can use a global variable in any text input field that displays the 🌐 icon.

Langflow stores global variables in its internal database, and encrypts the values using a secret key.

Create a global variable​

  1. In the Langflow UI, click your profile icon, and then select Settings.

  2. Click Global Variables.

  3. Click Add New.

  4. In the Create Variable dialog, enter a name for your variable in the Variable Name field.

  5. Optional: Select a Type for your global variable. The available types are Generic (default) and Credential.

    No matter which Type you select, Langflow still encrypts the Value of the global variable.

  6. Enter the Value for your global variable.

  7. Optional: Use the Apply To Fields menu to select one or more fields that you want Langflow to automatically apply your global variable to. For example, if you select OpenAI API Key, Langflow will automatically apply the variable to any OpenAI API Key field.

  8. Click Save Variable.

You can now select your global variable from any text input field that displays the 🌐 icon.

info

Because values are encrypted, you can't view the actual values of your global variables. In Settings > Global Variables, the Value column shows the encrypted hash for Generic type variables, and shows nothing for Credential type variables.

Edit a global variable​

  1. In the Langflow UI, click your profile icon, and then select Settings.

  2. Click Global Variables.

  3. Click on the global variable you want to edit.

  4. In the Update Variable dialog, you can edit the following fields: Variable Name, Value, and Apply To Fields.

  5. Click Update Variable.

Delete a global variable​

warning

Deleting a global variable permanently deletes any references to it from your existing projects.

  1. In the Langflow UI, click your profile icon, and then select Settings.

  2. Click Global Variables.

  3. Click the checkbox next to the global variable that you want to delete.

  4. Click the Trash icon.

The global variable, and any existing references to it, are deleted.

Add global variables from the environment​

You can use the LANGFLOW_VARIABLES_TO_GET_FROM_ENVIRONMENT environment variable to source global variables from your runtime environment.

If you installed Langflow locally, you must define the LANGFLOW_VARIABLES_TO_GET_FROM_ENVIRONMENT environment variable in a .env file.

  1. Create a .env file and open it in your preferred editor.

  2. Add the LANGFLOW_VARIABLES_TO_GET_FROM_ENVIRONMENT environment variable as follows:


    _10
    LANGFLOW_VARIABLES_TO_GET_FROM_ENVIRONMENT=VARIABLE1,VARIABLE2

    Replace VARIABLE1,VARIABLE2 with a comma-separated list (no spaces) of variables that you want Langflow to source from the environment. For example, my_key,some_string.

  3. Save and close the file.

  4. Start Langflow with the .env file:


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    VARIABLE1="VALUE1" VARIABLE2="VALUE2" python -m langflow run --env-file .env

    note

    In this example, the environment variables (VARIABLE1="VALUE1" and VARIABLE2="VALUE2") are prefixed to the startup command. This is a rudimentary method for exposing environment variables to Python on the command line, and is meant for illustrative purposes. Make sure to expose your environment variables to Langflow in a manner that best suits your own environment.

  5. Confirm that Langflow successfully sourced the global variables from the environment.

    1. In the Langflow UI, click your profile icon, and then select Settings.

    2. Click Global Variables.

    The environment variables appear in the list of Global Variables.

info

When adding global variables from the environment, the following limitations apply:

  • You can only source the Name and Value from the environment. To add additional parameters, such as the Apply To Fields parameter, you must edit the global variables in the Langflow UI.

  • Global variables that you add from the the environment always have the Credential type.

tip

If you want to explicitly prevent Langflow from sourcing global variables from the environment, set LANGFLOW_STORE_ENVIRONMENT_VARIABLES to false in your .env file:


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LANGFLOW_STORE_ENVIRONMENT_VARIABLES=false

Precautions​

Even though Langflow stores global variables in its internal database, and encrypts the values using a secret key, you should consider taking extra precautions to ensure the database and secret key are protected.

Use a custom secret key​

By default, Langflow generates a random secret key. However, you should provide your own secret key, as it's more secure to use a key that is already known to you.

Use the LANGFLOW_SECRET_KEY environment variable to provide a custom value for the secret key when you start Langflow.

Protect the secret key​

Make sure to store the secret key in a secure location.

By default, Langflow stores the secret key in its configuration directory. The location of the configuration directory depends on your operating system:

  • macOS: ~/Library/Caches/langflow/secret_key
  • Linux: ~/.cache/langflow/secret_key
  • Windows: %USERPROFILE%\AppData\Local\langflow\secret_key

To change the location of the the configuration directory, and thus the location of the secret key, set the LANGFLOW_CONFIG_DIR environment variable to your preferred storage directory.

Protect the database​

Make sure to store Langflow's internal database file in a secure location, and take regular backups to prevent accidental data loss.

By default, Langflow stores the database file in its installation directory. The location of the file depends on your operating system and installation method:

  • macOS: PYTHON_LOCATION/site-packages/langflow/langflow.db
  • Linux: PYTHON_LOCATION/site-packages/langflow/langflow.db
  • Windows: PYTHON_LOCATION\Lib\site-packages\langflow\langflow.db

To change the location of the database file, follow these steps:

  1. Set the LANGFLOW_SAVE_DB_IN_CONFIG_DIR environment variable to true.
  2. Set the LANGFLOW_CONFIG_DIR environment variable to your preferred storage directory.

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