Protobuf support (#13)

This uses tree-sitter-proto to parse the Procol Buffer schema file
for Protobuf extractor.

In addition, since `proto_library` typically requires accompanying
rules, I've added `secondary_rules` map, which will generate
rules within the same `BUILD.bazel` (as opposed to relying on macros).
The dependency relationship between the main target and the secondaries
can be specified using `extra_key_to_list` as
`"deps": [":${name}"]`.

.github/ci_scripts/integration_test.sh

@@ -5,7 +5,7 @@ set -o nounset  # abort on unbound variable
 set -o pipefail # don't hide errors within pipes
 
 cd example
-# TOOLING_WORKING_DIRECTORY=/tmp/bzl-gen-build source build_tools/lang_support/create_lang_build_files/regenerate_protos_build_files.sh
+TOOLING_WORKING_DIRECTORY=/tmp/bzl-gen-build source build_tools/lang_support/create_lang_build_files/regenerate_protos_build_files.sh
 TOOLING_WORKING_DIRECTORY=/tmp/bzl-gen-build source build_tools/lang_support/create_lang_build_files/regenerate_python_build_files.sh
 bazel test ...
 

DEVELOPING.md

@@ -0,0 +1,106 @@
+# Building
+
+Run this first to build everything.
+
+```bash
+./prepare_all_apps.sh
+```
+
+# Testing
+
+Run the following to test using the example repo:
+
+```
+.github/ci_scripts/integration_test.sh
+```
+
+Or export `REPO_PATH` to be the path of the Bazel repo your working on here...
+
+```bash
+# Pick jvm or python
+
+ECOSYSTEM=jvm
+ECOSYSTEM=python
+ECOSYSTEM=protos
+
+cargo run --bin bzl_gen_build_driver --release -- \
+  --input-path build_tools/lang_support/create_lang_build_files/bazel_${ECOSYSTEM}_modules.json \
+  --working-directory $REPO_PATH \
+  --cache-path ~/.cache/bazel_codegen \
+  extract \
+  --extractor protos:/tmp/bzl-gen-build/protos-entity-extractor \
+  --extractor java:/tmp/bzl-gen-build/java-entity-extractor \
+  --extractor scala:/tmp/bzl-gen-build/scala-entity-extractor \
+  --extractor python:/tmp/bzl-gen-build/python-entity-extractor \
+  --extracted-mappings /tmp/extracted_mappings.${ECOSYSTEM}.json
+
+cargo run --bin bzl_gen_build_driver  --release -- \
+  --input-path build_tools/lang_support/create_lang_build_files/bazel_${ECOSYSTEM}_modules.json \
+  --working-directory $REPO_PATH \
+  --cache-path ~/.cache/bazel_codegen \
+  extract-defs \
+  --extracted-mappings /tmp/extracted_mappings.${ECOSYSTEM}.json \
+  --extracted-defs /tmp/extracted_defs.${ECOSYSTEM}.json
+
+cargo run --bin bzl_gen_build_driver --release -- \
+  --input-path build_tools/lang_support/create_lang_build_files/bazel_${ECOSYSTEM}_modules.json \
+  --working-directory $REPO_PATH \
+  --cache-path ~/.cache/bazel_codegen \
+  build-graph \
+  --extracted-mappings /tmp/extracted_mappings.${ECOSYSTEM}.json \
+  --extracted-defs /tmp/extracted_defs.${ECOSYSTEM}.json \
+  --graph-out /tmp/graph_data.${ECOSYSTEM}.json
+
+cargo run --bin bzl_gen_build_driver --release -- \
+  --input-path build_tools/lang_support/create_lang_build_files/bazel_${ECOSYSTEM}_modules.json \
+  --working-directory $REPO_PATH \
+  --cache-path ~/.cache/bazel_codegen \
+  print-build \
+  --graph-data /tmp/graph_data.${ECOSYSTEM}.json
+```
+
+Shared API type from languages:
+
+```javascript
+    {
+        # A remote label @pip_... or local repo relative path src/a/b/c
+        "label_or_repo_path": ""
+
+        # List of objects defined in this file/target
+        "defs": [],
+
+        # List of references to other things defined in this target
+        "refs": [],
+
+        # List of commands that can be supplied to bzl_build_gen
+        # These are for special cases
+        #
+        # `ref` Add a manual reference to the specified def even though it didn't exist in this file
+        # `unref` Remove a reference seen in this file
+        # `def` Add a manual definition in this file on something that isn't visible to the parsers of the file
+        # `undef` Remove a definition as seen in this file
+        # `runtime_ref` Add a runtime dependency in this file. This is a colored edge that can be upgraded to a ref if another file or something in the file uses it.
+        #
+        #    value(SrcDirective::Ref, tag("ref")),
+        #    value(SrcDirective::Unref, tag("unref")),
+        #    value(SrcDirective::Def, tag("def")),
+        #    value(SrcDirective::Undef, tag("undef")),
+        #    value(SrcDirective::RuntimeRef, tag("runtime_ref")),
+        #    value(SrcDirective::RuntimeUnref, tag("runtime_unref")),
+        bzl_gen_build_commands: []
+    }
+```
+
+
+# Implications on the rules/macros used in the repo..
+
+We expect to be able to supply the following keys generically:
+- `srcs` , list of per language source files
+- `deps` , list of dependencies from the graph
+- `runtime_deps`, list of dependencies used at runtime, but not compile time. (For some languages like python, a macro wrapping py_library can help merge this into deps)
+
+# Testing on the repo side
+
+```bash
+TOOLING_WORKING_DIRECTORY=/tmp/bzl-gen-build ./bazel run build_tools/lang_support/create_lang_build_files:regenerate_jvm_build_files
+```

crates/Cargo.toml

@@ -2,6 +2,7 @@
 
 members = [
     "driver",
+    "protobuf_extractor",
     "python_extractor",
     "python_utilities",
     "shared_types",