serverless · pgrzesik · Jan 14, 2021 · Jan 4, 2021 · Jan 5, 2021 · Jan 7, 2021
diff --git a/docs/deprecations.md b/docs/deprecations.md
@@ -10,6 +10,16 @@ layout: Doc
 
 To disable specific deprecations set `SLS_DEPRECATION_DISABLE` environment variable. Setting `SLS_DEPRECATION_DISABLE=*` will disable all deprecations. If you want to disable specific deprecations set `SLS_DEPRECATION_DISABLE=CODE1,CODE2`.
 
+<a name="VARIABLES_ERROR_ON_UNRESOLVED"><div>&nbsp;</div></a>
+
+## Erroring on unresolved variable references
+
+Deprecation code: `VARIABLES_ERROR_ON_UNRESOLVED`
+
+Starting with v3.0.0, references to variables that cannot be resolved will result in an error being thrown.
+
+Adapt to this behaviour now by adding `unresolvedVariablesNotificationMode: error` to service configuration.
+
 <a name="AWS_API_GATEWAY_SPECIFIC_KEYS"><div>&nbsp;</div></a>
 
 ## API Gateway specific configuration

diff --git a/docs/providers/aws/guide/serverless.yml.md b/docs/providers/aws/guide/serverless.yml.md
@@ -24,6 +24,7 @@ service: myService
 frameworkVersion: '2'
 enableLocalInstallationFallback: false # If set to 'true', guarantees that it's a locally (for service, in its node_modules) installed framework which processes the command
 useDotenv: false # If set to 'true', environment variables will be automatically loaded from .env files
+unresolvedVariablesNotificationMode: warn # If set to 'error', references to variables that cannot be resolved will result in an error being thrown
 
 disabledDeprecations: # Disable deprecation logs by their codes. Default is empty.
   - DEP_CODE_1 # Deprecation code to disable

diff --git a/docs/providers/aws/guide/variables.md b/docs/providers/aws/guide/variables.md
@@ -18,6 +18,9 @@ Variables allow users to dynamically replace config values in `serverless.yml` c
 
 They are especially useful when providing secrets for your service to use and when you are working with multiple stages.
 
+If `unresolvedVariablesNotificationMode` is set to `error`, references to variables that cannot be resolved will result in an error being thrown.
+This will become the default behaviour in the next major version.
+
 ## Syntax
 
 To use variables, you will need to reference values enclosed in `${}` brackets.

diff --git a/lib/classes/Service.js b/lib/classes/Service.js
@@ -146,6 +146,7 @@ class Service {
     this.functions = serverlessFile.functions || {};
     this.configValidationMode = serverlessFile.configValidationMode || 'warn';
     this.disabledDeprecations = serverlessFile.disabledDeprecations;
+    this.unresolvedVariablesNotificationMode = serverlessFile.unresolvedVariablesNotificationMode;
 
     // merge so that the default settings are still in place and
     // won't be overwritten

diff --git a/lib/classes/Variables.js b/lib/classes/Variables.js
@@ -389,7 +389,7 @@ class Variables {
   renderMatches(value, matches, results) {
     let result = value;
     for (let i = 0; i < matches.length; i += 1) {
-      this.warnIfNotFound(matches[i].variable, results[i]);
+      this.handleUnresolved(matches[i].variable, results[i]);
       result = this.populateVariable(result, matches[i].match, results[i]);
     }
     return result;
@@ -962,33 +962,53 @@ class Variables {
     );
   }
 
-  warnIfNotFound(variableString, valueToPopulate) {
-    if (
+  handleUnresolved(variableString, valueToPopulate) {
+    const isValueEmpty =
       valueToPopulate === null ||
       typeof valueToPopulate === 'undefined' ||
       (typeof valueToPopulate === 'object' &&
         !Array.isArray(valueToPopulate) &&
-        !Object.keys(valueToPopulate).length)
-    ) {
-      let varType;
-      if (variableString.match(this.envRefSyntax)) {
-        varType = 'environment variable';
-      } else if (variableString.match(this.optRefSyntax)) {
-        varType = 'option';
-      } else if (variableString.match(this.selfRefSyntax)) {
-        varType = 'service attribute';
-      } else if (variableString.match(this.fileRefSyntax)) {
-        varType = 'file';
-      } else if (variableString.match(this.ssmRefSyntax)) {
-        varType = 'SSM parameter';
-      }
-      if (varType) {
-        logWarning(
-          `A valid ${varType} to satisfy the declaration '${variableString}' could not be found.`
-        );
-      }
+        !Object.keys(valueToPopulate).length);
+
+    if (!isValueEmpty) {
+      return;
+    }
+
+    let varType;
+
+    if (variableString.match(this.envRefSyntax)) {
+      varType = 'environment variable';
+    } else if (variableString.match(this.optRefSyntax)) {
+      varType = 'option';
+    } else if (variableString.match(this.selfRefSyntax)) {
+      varType = 'service attribute';
+    } else if (variableString.match(this.fileRefSyntax)) {
+      varType = 'file';
+    } else if (variableString.match(this.ssmRefSyntax)) {
+      varType = 'SSM parameter';
+    }
+
+    if (!varType) {
+      return;
     }
-    return valueToPopulate;
+
+    if (this.service.unresolvedVariablesNotificationMode === 'error') {
+      throw new this.serverless.classes.Error(
+        `A valid ${varType} to satisfy the declaration '${variableString}' could not be found.`,
+        'UNRESOLVED_CONFIG_VARIABLE'
+      );
+    }
+
+    if (!this.service.unresolvedVariablesNotificationMode) {
+      this.serverless._logDeprecation(
+        'VARIABLES_ERROR_ON_UNRESOLVED',
+        'Unresolved variable references will be communicated with a thrown error, starting from next major'
+      );
+    }
+
+    logWarning(
+      `A valid ${varType} to satisfy the declaration '${variableString}' could not be found.`
+    );
   }
 }
 

diff --git a/lib/configSchema.js b/lib/configSchema.js
@@ -120,6 +120,7 @@ const schema = {
         },
       ],
     },
+    unresolvedVariablesNotificationMode: { enum: ['error', 'warn'] },
     useDotenv: { const: true },
   },
   additionalProperties: false,
-Original file line number
+Diff line change
@@ Expand Up / @@ -120,6 +120,7 @@ const schema = { @@
             },
           ],
         },
+        unresolvedVariablesNotificationMode: { enum: ['error', 'warn'] },
         useDotenv: { const: true },
       },
       additionalProperties: false,
@@ Expand Down @@