Added a prototype for generating jsonschema files

Dockerfile.jsonschema

@@ -0,0 +1,10 @@
+# 3.18.2
+FROM alpine@sha256:25fad2a32ad1f6f510e528448ae1ec69a28ef81916a004d3629874104f8a7f70
+RUN apk add --update protoc=3.21.12-r2 protobuf-dev=3.21.12-r2 go=1.20.5-r0 git=2.40.1-r0
+RUN go install github.com/chrusty/protoc-gen-jsonschema/cmd/protoc-gen-jsonschema@1.4.1
+# This is required to get the field_behavior.proto file
+# NOTE: --filter=tree:0 performs a treeless clone; we do this to optimize cloning
+# this otherwise relatively heavy repository.
+RUN git clone --filter=tree:0 https://github.com/googleapis/googleapis.git \
+    && cd googleapis \
+    && git checkout 95f0f2b2aee51e460646320d6e8f2ce75c463f5a

Makefile

@@ -14,9 +14,10 @@
 # limitations under the License.
 
 PROTOC_IMAGE=protobuf-specs-build
+JSONSCHEMA_IMAGE=jsonschema-specs-build
 
 # generate all language protobuf code
-all: go python typescript ruby rust
+all: go python typescript ruby rust jsonschema
 
 # generate Go protobuf code
 go: docker-image
@@ -58,6 +59,14 @@ rust: docker-image
 		--entrypoint bash ${PROTOC_IMAGE} \
 		-c "cd gen/pb-rust/codegen && cargo run && rm -rf target/"
 
+jsonschema: docker-image-jsonschema
+	@echo "Generating JSON schema files"
+	docker run \
+	       --platform linux/amd64 \
+	       -v ${PWD}:/defs \
+	       --entrypoint sh \
+	       ${JSONSCHEMA_IMAGE} \
+	       -c "cd defs/gen/jsonschema && ./jsonschema.sh -I ../../protos -I /googleapis/ --jsonschema_out=schemas ../../protos/*.proto"
 
 # docker already does its own caching so we can attempt a build every time
 .PHONY: docker-image
@@ -73,6 +82,11 @@ docker-image-no-cache:
 	@echo "Building development docker image with disabled cache"
 	docker build --no-cache -t ${PROTOC_IMAGE} .
 
+.PHONY: docker-image-jsonschema
+docker-image-jsonschema:
+	@echo "Building docker image for generating JSON schema files"
+	docker build -t ${JSONSCHEMA_IMAGE} -f Dockerfile.jsonschema .
+
 # clean up generated files (not working? try sudo make clean)
 clean:
 	rm -rf gen/pb-go \

gen/jsonschema/jsonschema.sh

@@ -0,0 +1,10 @@
+#!/bin/sh
+
+set -u
+set -e
+
+protoc --plugin=/root/go/bin/protoc-gen-jsonschema \
+       --jsonschema_opt=enforce_oneof \
+       --jsonschema_opt=file_extension=schema.json \
+       --jsonschema_opt=disallow_additional_properties \
+       "$@"

gen/jsonschema/schemas/Artifact.schema.json

@@ -0,0 +1,35 @@
+{
+    "$schema": "http://json-schema.org/draft-04/schema#",
+    "$ref": "#/definitions/Artifact",
+    "definitions": {
+        "Artifact": {
+            "properties": {
+                "artifact_uri": {
+                    "type": "string",
+                    "description": "Location of the artifact"
+                },
+                "artifact": {
+                    "type": "string",
+                    "description": "The raw bytes of the artifact",
+                    "format": "binary",
+                    "binaryEncoding": "base64"
+                }
+            },
+            "additionalProperties": false,
+            "type": "object",
+            "oneOf": [
+                {
+                    "required": [
+                        "artifact_uri"
+                    ]
+                },
+                {
+                    "required": [
+                        "artifact"
+                    ]
+                }
+            ],
+            "title": "Artifact"
+        }
+    }
+}