package sihl
Install
Dune Dependency
Authors
Maintainers
Sources
sha256=77f0813d75a88edd14b3396e8b848d94c31c28803299b4b1bd4b78b1de4a2e80
sha512=a8907bc35ea14b7c3a7d638979a2a274860202b2de58b84b5621a4908db001ace493d8aa2e5383f4c8b1847efd256938592f63ef75a41521284b3640d3a7442a
doc/sihl.core/Sihl_core/Configuration/index.html
Module Sihl_core.ConfigurationSource
A module to manage service configurations.
An app’s configuration is everything that is likely to vary between deploys (staging, production, developer environments, etc).
This includes:
- Resource handles to the database, Memcached, and other backing services
- Credentials to external services such as Amazon S3 or Twitter
- Per-deploy values such as the canonical hostname for the deploy
(Source: https://12factor.net/config)
Configuration
A list of key-value pairs of strings representing the configuration key like SMTP_HOST and a value.
The configuration contains configuration data and a configuration schema.
make schema data returns a configuration containing the configuration schema and the configuration data.
commands configurations returns the list of CLI commands given a list of configurations.
Storing configuration
Configuration might come from various sources like .env files, environment variables or as data provided directly to services or the app.
A configuration is a list of key-value string pairs.
Reading configuration
Using the schema validator conformist it is easy to validate and decode configuration values. Conformist schemas can express a richer set of requirements than static types, which can be used in services to validate configurations at start time.
Validating configuration when starting services can lead to run-time exceptions, but they occur early in the app lifecycle. This minimizes the feedback loop and makes sure, that services start only with valid configuration.
project_root_path contains the path to the root of the project/app. Its value is known at app start, thus not requiring it to be a function. It reads the value of PROJECT_ROOT_PATH. If that env variable is not set, it reads the current working directory of the process.
read_env_file () reads an .env file from the project root directory and returns the key-value pairs as data. If SIHL_ENV is set to test, .env.testing is read. Otherwise .env is read. If the file doesn't exist, empty data is returned.
read schema returns the decoded, statically typed version of configuration t of the schema. This is used in services to declaratively define a valid configuration.
The configuration data t is merged with the environment variable and, if present, an .env file.
It fails with Exception and prints descriptive message of invalid configuration.
read_string key returns the configuration value with key if present. The function is memoized, the first call caches the returned value and subsequent calls are fast.
read_int key returns the configuration value with key if present. the first call caches the returned value and subsequent calls are fast.
read_bool key returns the configuration value with key if present. the first call caches the returned value and subsequent calls are fast.
is_testing () returns true if Sihl is running in a test environment, meaning if tests are executing parts of Sihl.
is_production () returns true if Sihl is running in a production environment.