Example to show how bundle variables work

knowledge_base/bundle_variables/.gitignore

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+.databricks

knowledge_base/bundle_variables/README.md

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+# bundle_variables
+
+Example to show how bundle variables work.
+
+We will focus on the behavior of the variables section alone. To do so, we exclusively use
+the `validate` command, and use its JSON output mode to focus on the variables section.
+
+## Usage
+
+Configure the workspace to use:
+```sh
+export DATABRICKS_CONFIG_PROFILE="<workspace profile>"
+```
+
+Try to run validate without arguments:
+```sh
+databricks bundle validate --output json | jq .variables
+```
+
+Because the configuration includes a variable definition without a value, it returns an error
+saying that the value must be defined:
+```
+Error: no value assigned to required variable "no_default".
+```
+
+Assign a value for this variable by either:
+
+1. Adding a `--var` flag to all bundle commands:
+```sh
+databricks bundle validate --var no_default="injected value"
+```
+
+2. Configuring an environment variable:
+```sh
+export BUNDLE_VAR_no_default="injected value"
+```
+
+Now, try to run validate again, and observe that it passes:
+```sh
+databricks bundle validate --var no_default="injected value" --output json | jq .variables
+```
+
+Example output:
+```json
+{
+  "no_default": {
+    "description": "This is a variable with no default value",
+    "value": "injected value"
+  },
+  "with_default": {
+    "description": "This is a variable with a default value",
+    "value": "hello"
+  },
+  "with_default_in_targets": {
+    "default": "value_in_development",
+    "description": "This is a variable with its default value defined in the targets section",
+    "value": "value_in_development"
+  }
+}
+```
+
+What we've seen:
+* The `no_default` variable is defined with the value we injected.
+* The `with_default` variable is defined with the default value.
+* The `with_default_in_targets` variable is defined with the value from the targets section.

knowledge_base/bundle_variables/databricks.yml

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+bundle:
+  name: bundle_variables
+
+variables:
+  no_default:
+    description: This is a variable with no default value
+
+  with_default:
+    description: This is a variable with a default value
+    value: hello
+
+  with_default_in_targets:
+    description: This is a variable with its default value defined in the targets section
+
+targets:
+  development:
+    default: true
+
+    variables:
+      with_default_in_targets: value_in_development
+
+  production:
+    variables:
+      with_default_in_targets: value_in_production