Adding function metadata validation for missing or invalid bindings (#3085)

Author: soninaren

src/WebJobs.Script/Description/FunctionDescriptorProvider.cs

@@ -42,6 +42,7 @@ public virtual bool TryCreate(FunctionMetadata functionMetadata, out FunctionDes
             // parse the bindings
             Collection<FunctionBinding> inputBindings = FunctionBinding.GetBindings(Config, functionMetadata.InputBindings, FileAccess.Read);
             Collection<FunctionBinding> outputBindings = FunctionBinding.GetBindings(Config, functionMetadata.OutputBindings, FileAccess.Write);
+            VerifyResolvedBindings(functionMetadata, inputBindings, outputBindings);
 
             BindingMetadata triggerMetadata = functionMetadata.InputBindings.FirstOrDefault(p => p.IsTrigger);
             string scriptFilePath = Path.Combine(Config.RootScriptPath, functionMetadata.ScriptFile ?? string.Empty);
@@ -72,6 +73,20 @@ public virtual bool TryCreate(FunctionMetadata functionMetadata, out FunctionDes
             }
         }
 
+        public void VerifyResolvedBindings(FunctionMetadata functionMetadata, IEnumerable<FunctionBinding> inputBindings, IEnumerable<FunctionBinding> outputBindings)
+        {
+            IEnumerable<string> bindingsFromMetadata = functionMetadata.InputBindings.Union(functionMetadata.OutputBindings).Select(f => f.Type);
+            IEnumerable<string> resolvedBindings = inputBindings.Union(outputBindings).Select(b => b.Metadata.Type);
+            IEnumerable<string> unresolvedBindings = bindingsFromMetadata.Except(resolvedBindings);
+
+            if (unresolvedBindings.Any())
+            {
+                string allUnresolvedBindings = string.Join(", ", unresolvedBindings);
+                throw new ScriptConfigurationException($"The binding type(s) '{allUnresolvedBindings}' are not registered. " +
+                        $"Please ensure the type is correct and the binding extension is installed.");
+            }
+        }
+
         protected virtual Collection<ParameterDescriptor> GetFunctionParameters(IFunctionInvoker functionInvoker, FunctionMetadata functionMetadata,
             BindingMetadata triggerMetadata, Collection<CustomAttributeBuilder> methodAttributes, Collection<FunctionBinding> inputBindings, Collection<FunctionBinding> outputBindings)
         {

test/WebJobs.Script.Tests/Description/FunctionDescriptorProviderTests.cs

@@ -80,6 +80,45 @@ public void ValidateFunction_NoTriggerBinding_Throws()
             Assert.Equal("No trigger binding specified. A function must have a trigger input binding.", ex.Message);
         }
 
+        [Fact]
+        public void VerifyResolvedBindings_WithNoBindingMatch_ThrowsExpectedException()
+        {
+            FunctionMetadata functionMetadata = new FunctionMetadata();
+            BindingMetadata triggerMetadata = BindingMetadata.Create(JObject.Parse("{\"type\": \"blobTrigger\",\"name\": \"req\",\"direction\": \"in\"}"));
+            BindingMetadata bindingMetadata = BindingMetadata.Create(JObject.Parse("{\"type\": \"unknownbinding\",\"name\": \"blob\",\"direction\": \"in\"}"));
+
+            functionMetadata.Bindings.Add(triggerMetadata);
+            functionMetadata.Bindings.Add(bindingMetadata);
+
+            var ex = Assert.Throws<ScriptConfigurationException>(() =>
+            {
+                _provider.TryCreate(functionMetadata, out FunctionDescriptor descriptor);
+            });
+
+            Assert.Contains("unknownbinding", ex.Message);
+        }
+
+        [Fact]
+        public void VerifyResolvedBindings_WithValidBindingMatch_DoesNotThrow()
+        {
+            FunctionMetadata functionMetadata = new FunctionMetadata();
+            BindingMetadata triggerMetadata = BindingMetadata.Create(JObject.Parse("{\"type\": \"httpTrigger\",\"name\": \"req\",\"direction\": \"in\"}"));
+            BindingMetadata bindingMetadata = BindingMetadata.Create(JObject.Parse("{\"type\": \"http\",\"name\": \"$return\",\"direction\": \"out\"}"));
+
+            functionMetadata.Bindings.Add(triggerMetadata);
+            functionMetadata.Bindings.Add(bindingMetadata);
+            try
+            {
+                _provider.TryCreate(functionMetadata, out FunctionDescriptor descriptor);
+                Assert.True(true, "No exception thrown");
+            }
+            catch (Exception ex)
+            {
+                Assert.True(false, "Exception not expected:" + ex.Message);
+                throw;
+            }
+        }
+
         [Fact]
         public void CreateTriggerParameter_WithNoBindingMatch_ThrowsExpectedException()
         {