Merge pull request #138 from scalar-labs/add-updated-docs

Add updated configurations doc for ScalarDB

docs/3.10/configurations.md

@@ -167,6 +167,19 @@ The following are additional configurations available for ScalarDB:
 | `scalar.db.active_transaction_management.expiration_time_millis` | ScalarDB maintains ongoing transactions, which can be resumed by using a transaction ID. This setting specifies the expiration time of this transaction management feature in milliseconds.                       | `-1` (no expiration) |
 | `scalar.db.default_namespace_name`                               | The given namespace name will be used by operations that do not already specify a namespace. |                      |
 
+## Placeholder usage
+
+You can use placeholders in the values, and they are replaced with environment variables (`${env:<ENVIRONMENT_VARIABLE_NAME>}`) or system properties (`${sys:<SYSTEM_PROPERTY_NAME>}`). You can also specify default values in placeholders like `${sys:<SYSTEM_PROPERTY_NAME>:-<DEFAULT_VALUE>}`.
+
+The following is an example of a configuration that uses placeholders:
+
+```properties
+scalar.db.username=${env:<SCALAR_DB_USERNAME>:-admin}
+scalar.db.password=${env:<SCALAR_DB_PASSWORD>}
+```
+
+In this example configuration, ScalarDB reads the username and password from environment variables. If the environment variable `SCALAR_DB_USERNAME` does not exist, ScalarDB uses the default value `admin`.
+
 ## Configuration examples
 
 This section provides some configuration examples.

docs/3.11/configurations.md

@@ -188,6 +188,19 @@ The following are additional configurations available for ScalarDB:
 | `scalar.db.active_transaction_management.expiration_time_millis` | ScalarDB maintains ongoing transactions, which can be resumed by using a transaction ID. This setting specifies the expiration time of this transaction management feature in milliseconds. | `-1` (no expiration) |
 | `scalar.db.default_namespace_name`                               | The given namespace name will be used by operations that do not already specify a namespace.                                                                                                |                      |
 
+## Placeholder usage
+
+You can use placeholders in the values, and they are replaced with environment variables (`${env:<ENVIRONMENT_VARIABLE_NAME>}`) or system properties (`${sys:<SYSTEM_PROPERTY_NAME>}`). You can also specify default values in placeholders like `${sys:<SYSTEM_PROPERTY_NAME>:-<DEFAULT_VALUE>}`.
+
+The following is an example of a configuration that uses placeholders:
+
+```properties
+scalar.db.username=${env:<SCALAR_DB_USERNAME>:-admin}
+scalar.db.password=${env:<SCALAR_DB_PASSWORD>}
+```
+
+In this example configuration, ScalarDB reads the username and password from environment variables. If the environment variable `SCALAR_DB_USERNAME` does not exist, ScalarDB uses the default value `admin`.
+
 ## Configuration examples
 
 This section provides some configuration examples.

docs/3.8/configurations.md

@@ -180,6 +180,19 @@ The following are additional configurations available for ScalarDB:
 | `scalar.db.metadata.cache_expiration_time_secs`                  | ScalarDB has a metadata cache to reduce the number of requests to the database. This setting specifies the expiration time of the cache in seconds.                                                               | `-1` (no expiration) |
 | `scalar.db.active_transaction_management.expiration_time_millis` | ScalarDB maintains ongoing transactions, which can be resumed by using a transaction ID. This setting specifies the expiration time of this transaction management feature in milliseconds.                       | `-1` (no expiration) |
 
+## Placeholder usage
+
+You can use placeholders in the values, and they are replaced with environment variables (`${env:<ENVIRONMENT_VARIABLE_NAME>}`) or system properties (`${sys:<SYSTEM_PROPERTY_NAME>}`). You can also specify default values in placeholders like `${sys:<SYSTEM_PROPERTY_NAME>:-<DEFAULT_VALUE>}`.
+
+The following is an example of a configuration that uses placeholders:
+
+```properties
+scalar.db.username=${env:<SCALAR_DB_USERNAME>:-admin}
+scalar.db.password=${env:<SCALAR_DB_PASSWORD>}
+```
+
+In this example configuration, ScalarDB reads the username and password from environment variables. If the environment variable `SCALAR_DB_USERNAME` does not exist, ScalarDB uses the default value `admin`.
+
 ## Configuration examples
 
 This section provides some configuration examples.

docs/3.9/configurations.md

@@ -167,6 +167,19 @@ The following are additional configurations available for ScalarDB:
 | `scalar.db.active_transaction_management.expiration_time_millis` | ScalarDB maintains ongoing transactions, which can be resumed by using a transaction ID. This setting specifies the expiration time of this transaction management feature in milliseconds.                       | `-1` (no expiration) |
 | `scalar.db.default_namespace_name`                               | The given namespace name will be used by operations that do not already specify a namespace. |                      |
 
+## Placeholder usage
+
+You can use placeholders in the values, and they are replaced with environment variables (`${env:<ENVIRONMENT_VARIABLE_NAME>}`) or system properties (`${sys:<SYSTEM_PROPERTY_NAME>}`). You can also specify default values in placeholders like `${sys:<SYSTEM_PROPERTY_NAME>:-<DEFAULT_VALUE>}`.
+
+The following is an example of a configuration that uses placeholders:
+
+```properties
+scalar.db.username=${env:<SCALAR_DB_USERNAME>:-admin}
+scalar.db.password=${env:<SCALAR_DB_PASSWORD>}
+```
+
+In this example configuration, ScalarDB reads the username and password from environment variables. If the environment variable `SCALAR_DB_USERNAME` does not exist, ScalarDB uses the default value `admin`.
+
 ## Configuration examples
 
 This section provides some configuration examples.

docs/latest/configurations.md

@@ -188,6 +188,19 @@ The following are additional configurations available for ScalarDB:
 | `scalar.db.active_transaction_management.expiration_time_millis` | ScalarDB maintains ongoing transactions, which can be resumed by using a transaction ID. This setting specifies the expiration time of this transaction management feature in milliseconds. | `-1` (no expiration) |
 | `scalar.db.default_namespace_name`                               | The given namespace name will be used by operations that do not already specify a namespace.                                                                                                |                      |
 
+## Placeholder usage
+
+You can use placeholders in the values, and they are replaced with environment variables (`${env:<ENVIRONMENT_VARIABLE_NAME>}`) or system properties (`${sys:<SYSTEM_PROPERTY_NAME>}`). You can also specify default values in placeholders like `${sys:<SYSTEM_PROPERTY_NAME>:-<DEFAULT_VALUE>}`.
+
+The following is an example of a configuration that uses placeholders:
+
+```properties
+scalar.db.username=${env:<SCALAR_DB_USERNAME>:-admin}
+scalar.db.password=${env:<SCALAR_DB_PASSWORD>}
+```
+
+In this example configuration, ScalarDB reads the username and password from environment variables. If the environment variable `SCALAR_DB_USERNAME` does not exist, ScalarDB uses the default value `admin`.
+
 ## Configuration examples
 
 This section provides some configuration examples.