feat: Add a Protobuf event formatter

Further features may be added later, e.g. convenience methods.

Signed-off-by: Jon Skeet <[email protected]>

Author: jskeet

CloudEvents.sln

@@ -33,7 +33,9 @@ Project("{9A19103F-16F7-4668-BE54-9A1E7A4F7556}") = "CloudNative.CloudEvents.Avr
 EndProject
 Project("{9A19103F-16F7-4668-BE54-9A1E7A4F7556}") = "CloudNative.CloudEvents.NewtonsoftJson", "src\CloudNative.CloudEvents.NewtonsoftJson\CloudNative.CloudEvents.NewtonsoftJson.csproj", "{9DC17081-21D8-4123-8650-D97C2153DB8C}"
 EndProject
-Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "CloudNative.CloudEvents.SystemTextJson", "src\CloudNative.CloudEvents.SystemTextJson\CloudNative.CloudEvents.SystemTextJson.csproj", "{FACB3EF2-F078-479A-A91C-719894CB66BF}"
+Project("{9A19103F-16F7-4668-BE54-9A1E7A4F7556}") = "CloudNative.CloudEvents.SystemTextJson", "src\CloudNative.CloudEvents.SystemTextJson\CloudNative.CloudEvents.SystemTextJson.csproj", "{FACB3EF2-F078-479A-A91C-719894CB66BF}"
+EndProject
+Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "CloudNative.CloudEvents.Protobuf", "src\CloudNative.CloudEvents.Protobuf\CloudNative.CloudEvents.Protobuf.csproj", "{9D82AC2B-0075-4161-AE0E-4A6629C9FF2A}"
 EndProject
 Global
 	GlobalSection(SolutionConfigurationPlatforms) = preSolution
@@ -189,6 +191,18 @@ Global
 		{FACB3EF2-F078-479A-A91C-719894CB66BF}.Release|x64.Build.0 = Release|Any CPU
 		{FACB3EF2-F078-479A-A91C-719894CB66BF}.Release|x86.ActiveCfg = Release|Any CPU
 		{FACB3EF2-F078-479A-A91C-719894CB66BF}.Release|x86.Build.0 = Release|Any CPU
+		{9D82AC2B-0075-4161-AE0E-4A6629C9FF2A}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
+		{9D82AC2B-0075-4161-AE0E-4A6629C9FF2A}.Debug|Any CPU.Build.0 = Debug|Any CPU
+		{9D82AC2B-0075-4161-AE0E-4A6629C9FF2A}.Debug|x64.ActiveCfg = Debug|Any CPU
+		{9D82AC2B-0075-4161-AE0E-4A6629C9FF2A}.Debug|x64.Build.0 = Debug|Any CPU
+		{9D82AC2B-0075-4161-AE0E-4A6629C9FF2A}.Debug|x86.ActiveCfg = Debug|Any CPU
+		{9D82AC2B-0075-4161-AE0E-4A6629C9FF2A}.Debug|x86.Build.0 = Debug|Any CPU
+		{9D82AC2B-0075-4161-AE0E-4A6629C9FF2A}.Release|Any CPU.ActiveCfg = Release|Any CPU
+		{9D82AC2B-0075-4161-AE0E-4A6629C9FF2A}.Release|Any CPU.Build.0 = Release|Any CPU
+		{9D82AC2B-0075-4161-AE0E-4A6629C9FF2A}.Release|x64.ActiveCfg = Release|Any CPU
+		{9D82AC2B-0075-4161-AE0E-4A6629C9FF2A}.Release|x64.Build.0 = Release|Any CPU
+		{9D82AC2B-0075-4161-AE0E-4A6629C9FF2A}.Release|x86.ActiveCfg = Release|Any CPU
+		{9D82AC2B-0075-4161-AE0E-4A6629C9FF2A}.Release|x86.Build.0 = Release|Any CPU
 	EndGlobalSection
 	GlobalSection(SolutionProperties) = preSolution
 		HideSolutionNode = FALSE

generate_protos.sh

@@ -0,0 +1,67 @@
+#!/bin/bash
+# Copyright 2021 Cloud Native Foundation.
+# Licensed under the Apache 2.0 license.
+# See LICENSE file in the project root for full license information.
+
+set -e
+PROTOBUF_VERSION=3.19.3
+
+# Generates the classes for the protobuf event format
+
+case "$OSTYPE" in
+  linux*)
+    PROTOBUF_PLATFORM=linux-x86_64
+    PROTOC=tmp/bin/protoc
+    ;;
+  win* | msys* | cygwin*)
+    PROTOBUF_PLATFORM=win64
+    PROTOC=tmp/bin/protoc.exe
+    ;;
+  darwin*)
+    PROTOBUF_PLATFORM=osx-x86_64
+    PROTOC=tmp/bin/protoc
+    ;;
+  *)
+    echo "Unknown OSTYPE: $OSTYPE"
+    exit 1
+esac
+
+# Clean up previous generation results
+rm -f src/CloudNative.CloudEvents.Protobuf/*.g.cs
+rm -f test/CloudNative.CloudEvents.UnitTests/Protobuf/*.g.cs
+
+rm -rf tmp
+mkdir tmp
+cd tmp
+
+echo "- Downloading protobuf@$PROTOBUF_VERSION"
+curl -sSL \
+  https://github.com/protocolbuffers/protobuf/releases/download/v$PROTOBUF_VERSION/protoc-$PROTOBUF_VERSION-$PROTOBUF_PLATFORM.zip \
+  --output protobuf.zip
+unzip -q protobuf.zip
+
+echo "- Downloading schema"
+# TODO: Use the 1.0.2 branch when it exists.
+mkdir cloudevents
+curl -sSL https://raw.githubusercontent.com/cloudevents/spec/main/cloudevents/formats/cloudevents.proto -o cloudevents/ProtoSchema.proto
+
+cd ..
+
+# Schema proto
+$PROTOC \
+  -I tmp/include \
+  -I tmp/cloudevents \
+  --csharp_out=src/CloudNative.CloudEvents.Protobuf \
+  --csharp_opt=file_extension=.g.cs \
+  tmp/cloudevents/ProtoSchema.proto
+
+# Test protos
+$PROTOC \
+  -I tmp/include \
+  -I test/CloudNative.CloudEvents.UnitTests/Protobuf \
+  --csharp_out=test/CloudNative.CloudEvents.UnitTests/Protobuf \
+  --csharp_opt=file_extension=.g.cs \
+  test/CloudNative.CloudEvents.UnitTests/Protobuf/*.proto
+
+echo "Generated code."
+rm -rf tmp

src/CloudNative.CloudEvents.Protobuf/CloudNative.CloudEvents.Protobuf.csproj

@@ -0,0 +1,23 @@
+<Project Sdk="Microsoft.NET.Sdk">
+
+  <PropertyGroup>
+	<TargetFrameworks>netstandard2.0;netstandard2.1</TargetFrameworks>
+	<Description>Support for the Protobuf event format in for CloudNative.CloudEvents</Description>
+	<PackageTags>cncf;cloudnative;cloudevents;events;protobuf</PackageTags>
+	<LangVersion>8.0</LangVersion>
+	<Nullable>enable</Nullable>
+	<Version>2.0.0-local.1</Version>
+  </PropertyGroup>
+
+  <ItemGroup>
+    <PackageReference Include="Google.Protobuf" Version="3.19.3" />
+    
+    <!-- Be explicit about not including these files in the package. -->
+    <None Include="README.md" />
+  </ItemGroup>
+
+  <ItemGroup>
+    <ProjectReference Include="..\CloudNative.CloudEvents\CloudNative.CloudEvents.csproj" />
+  </ItemGroup>
+
+</Project>