docs(app-namespace): document using app namespace for backend name (#505)

* docs(app-namespace): document using app namespace for backend name

* docs: add cross link

Author: badmonster0

docs/docs/core/flow_def.mdx

@@ -311,6 +311,38 @@ Following metrics are supported:
 
 ## Miscellaneous
 
+### Getting App Namespace
+
+You can use the [`app_namespace` setting](initialization#app-namespace) or `COCOINDEX_APP_NAMESPACE` environment variable to specify the app namespace,
+to organize flows across different environments (e.g., dev, staging, production), team members, etc.
+
+In the code, You can call `flow.get_app_namespace()` to get the app namespace, and use it to name certain backends. It takes the following arguments:
+
+*   `trailing_delimiter` (optional): a string to append to the app namespace when it's not empty.
+
+e.g. when the current app namespace is `Staging`, `flow.get_app_namespace(trailing_delimiter='.')` will return `Staging.`.
+
+For example,
+
+<Tabs>
+<TabItem value="python" label="Python" default>
+
+```python
+doc_embeddings.export(
+    "doc_embeddings",
+    cocoindex.storages.Qdrant(
+        collection_name=cocoindex.get_app_namespace(trailing_delimiter='__') + "doc_embeddings",
+        ...
+    ),
+    ...
+)
+```
+
+</TabItem>
+</Tabs>
+
+It will use `Staging__doc_embeddings` as the collection name if the current app namespace is `Staging`, and use `doc_embeddings` if the app namespace is empty.
+
 ### Target Declarations
 
 Most time a target storage is created by calling `export()` method on a collector, and this `export()` call comes with configurations needed for the target storage, e.g. options for storage indexes.

docs/docs/core/initialization.mdx

@@ -88,9 +88,10 @@ if __name__ == "__main__":
 
 ### App Namespace
 
-The `app_namespace` field helps organize flows across different environments (e.g., testing, production) or teams. When set, it prefixes flow names with the namespace.
+The `app_namespace` field helps organize flows across different environments (e.g., dev, staging, production), team members, etc. When set, it prefixes flow names with the namespace.
 
-For example, if the namespace is "Staging", for a flow with name specified as `Flow1` in code, the full name of the flow will be `Staging.Flow1`.
+For example, if the namespace is `Staging`, for a flow with name specified as `Flow1` in code, the full name of the flow will be `Staging.Flow1`.
+You can also get the current app namespace by calling `cocoindex.get_app_namespace()` (see [Getting App Namespace](flow_def#getting-app-namespace) for more details).
 
 If not set, all flows are in a default unnamed namespace.
 

docs/docs/ops/storages.md

@@ -40,7 +40,7 @@ The spec takes the following fields:
     See [DatabaseConnectionSpec](../core/initialization#databaseconnectionspec) for its specific fields.
     If not provided, will use the same database as the [internal storage](/docs/core/basics#internal-storage).
 
-*   `table_name` (type: `str`, optional): The name of the table to store to. If unspecified, will generate a new automatically. We recommend specifying a name explicitly if you want to directly query the table. It can be omitted if you want to use CocoIndex's query handlers to query the table.
+*   `table_name` (type: `str`, optional): The name of the table to store to. If unspecified, will use the table name `[${AppNamespace}__]${FlowName}__${TargetName}`, e.g. `DemoFlow__doc_embeddings` or `Staging__DemoFlow__doc_embeddings`.
 
 ### Qdrant