Merge pull request #215 from dockersamples/labspace-defined-variables

Add labspace-defined variables for easier maintenance

Author: mikesir87

components/interface/api/src/services/labspace.js

@@ -35,6 +35,10 @@ export class LabspaceService {
         .replace(/[^a-z0-9\s-]/g, "") // remove special characters except spaces and dashes
         .replace(/\s+/g, "-"), // replace spaces with dashes
     }));
+
+    if (this.config.variables) {
+      this.variables = { ...this.config.variables };
+    }
   }
 
   getLabspaceDetails() {
@@ -85,7 +89,8 @@ export class LabspaceService {
         const value = has ? this.variables[key] : undefined;
         if (value === undefined || value === null) return key;
         return String(value);
-      });
+      })
+      .replace(/\\\$\\\$/g, "$$$$"); // Allow the usage of \$\$ to render as $$ in the markdown
 
     return {
       id: section.id,

docs/markdown-options.md

@@ -183,3 +183,26 @@ For values, the following options are available:
 - `requiredValue`: the value to match
 - `hasValue`: if set, the content will be shown if the variable has any value
 - `hasNoValue`: if set, the content will be shown if the variable is undefined or empty
+
+### Labspace-defined variables
+
+To support easier maintenance for values that may need to be updated in multiple locations, variables can also be defined in the `labspace.yaml` file. 
+
+For example, the following `labspace.yaml` configuration will define a variable named `pythonImageTag`:
+
+```yaml
+variables:
+  pythonImageTag: 3.14-alpine
+```
+
+It can be injected using the same variable syntax throughout the markdown:
+
+```dockerfile
+FROM python:$$pythonImageTag$$
+```
+
+will then render as:
+
+```dockerfile
+FROM python:3.14-alpine
+```

sample-content-repo/labspace/04-variables.md

@@ -57,3 +57,26 @@ Variables can be used to support the conditional displaying of text.
     > [!TIP]
     > It appears the conditional is set and this content is displayed!
     :::
+
+## Default Labspace variables
+
+As a help to authors, variables can also be defined in the `labspace.yaml` file to reduce maintenance where a value may appear in multiple places throughout the writeup. 
+
+For example, the following `labspace.yaml` configuration will define a variable named `pythonImageTag`:
+
+```yaml
+variables:
+  pythonImageTag: 3.14-alpine
+```
+
+It can be injected using the same variable syntax throughout the markdown:
+
+```dockerfile
+FROM python:\$\$pythonImageTag\$\$
+```
+
+will then render as:
+
+```dockerfile
+FROM python:$$pythonImageTag$$
+```

sample-content-repo/labspace/labspace.yaml

@@ -28,4 +28,10 @@ services:
   - id: app
     title: App
     url: http://localhost
-    icon: web
+    icon: web
+
+# Define variables that will be injected into the markdown context. Using variables makes maintenance easier
+# when the same value is used in multiple places. If desired, you can also allow these values to be overridden
+# by the end users.
+variables:
+  pythonImageTag: 3.14-alpine