Configuration

When initializing a new Preswald project with preswald init, a default preswald.toml file is created. This file defines core settings for the app, including logging, theming, and data connections. Data connections can include databases like PostgreSQL or local CSV files.

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Default Configuration (preswald.toml)

The following is the default structure of preswald.toml created during initialization:

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Example preswald.toml

[project]
title = "My Preswald App"
version = "0.1.0"
port = 8501

[branding]
name = "Preswald Project"
logo = "images/logo.png"
favicon = "images/favicon.ico"
primaryColor = "#F89613"

[data.postgres]
type = "postgres"
host = "localhost"
port = 5432
dbname = "example_db"
user = "user"

[data.csv]
type = "csv"
path = "data/example.csv"
delimiter = ","
header = true

[logging]
level = "INFO"  # Options: DEBUG, INFO, WARNING, ERROR, CRITICAL
format = "%(asctime)s - %(name)s - %(levelname)s - %(message)s"

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Configuration Sections

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[project]

• title: Name of the app displayed in the interface.
• version: Version of the app.
• port: Port the app runs on (default is 8501).

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[branding]

• name: Displayed name of the app.
• logo: Path to the logo file (relative to the project directory).
• favicon: Path to the favicon file.
• primaryColor: The primary UI color, specified as a CSS-compatible color (e.g., #3498db).

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Connecting to Data Sources

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PostgreSQL Example: [data.postgres]

• type: Use "postgres" for PostgreSQL.
• host: Hostname or IP of the database server.
• port: Port number for the database (default is 5432).
• dbname: Name of the database.
• user: Username for database access.

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CSV Example: [data.csv]

You can use a local CSV file as a data source by defining it in preswald.toml.

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Fields:

• type: Use "csv" to specify that this connection refers to a CSV file.
• path: Relative or absolute path to the CSV file.
• delimiter: The character used to separate values (e.g., , or ;).
• header: Set to true if the CSV file contains a header row, otherwise false.

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Example CSV Connection:

[data.csv]
type = "csv"
path = "data/customers.csv"
delimiter = ","
header = true

If the CSV file is located in a subdirectory, make sure the path is correct relative to the root directory.

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Logging Configuration

The [logging] section allows you to control the verbosity and format of logs generated by the app.

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Fields:

• level: Minimum severity level for log messages. Options:
  • DEBUG: Logs detailed debugging information.
  • INFO: Logs general app activity.
  • WARNING: Logs warnings or potential issues.
  • ERROR: Logs critical errors.
  • CRITICAL: Logs only severe issues that cause immediate failure.
• format: Specifies the format of the log messages. Common placeholders:
  • %(asctime)s: Timestamp of the log entry.
  • %(name)s: Name of the logger.
  • %(levelname)s: Severity level of the log.
  • %(message)s: Log message content.

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Example Logging Setup:

[logging]
level = "DEBUG"
format = "%(asctime)s - %(name)s - %(levelname)s - %(message)s"

This configuration generates detailed logs, including timestamps, logger names, and log messages.