From ed591391b672bc518aee43fcdcfdad6be26ef902 Mon Sep 17 00:00:00 2001
From: Pieter Noordhuis <pieter.noordhuis@databricks.com>
Date: Wed, 14 Feb 2024 10:24:54 +0100
Subject: [PATCH] Example to show how bundle variables work

---
 knowledge_base/bundle_variables/.gitignore    |  1 +
 knowledge_base/bundle_variables/README.md     | 65 +++++++++++++++++++
 .../bundle_variables/databricks.yml           | 24 +++++++
 3 files changed, 90 insertions(+)
 create mode 100644 knowledge_base/bundle_variables/.gitignore
 create mode 100644 knowledge_base/bundle_variables/README.md
 create mode 100644 knowledge_base/bundle_variables/databricks.yml

diff --git a/knowledge_base/bundle_variables/.gitignore b/knowledge_base/bundle_variables/.gitignore
new file mode 100644
index 0000000..15bcc6d
--- /dev/null
+++ b/knowledge_base/bundle_variables/.gitignore
@@ -0,0 +1 @@
+.databricks
diff --git a/knowledge_base/bundle_variables/README.md b/knowledge_base/bundle_variables/README.md
new file mode 100644
index 0000000..11b25ae
--- /dev/null
+++ b/knowledge_base/bundle_variables/README.md
@@ -0,0 +1,65 @@
+# 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.
diff --git a/knowledge_base/bundle_variables/databricks.yml b/knowledge_base/bundle_variables/databricks.yml
new file mode 100644
index 0000000..98bf9c2
--- /dev/null
+++ b/knowledge_base/bundle_variables/databricks.yml
@@ -0,0 +1,24 @@
+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