feat: support grpc plugins with ts and bun

[SkArchon]

This PR implements typescript plugins with bun.

• There are no changes in the router, because we build a binary in the same name format it expects {platform}-{arch}

• This PR also removes the template TS constants into template files, which are appended into the previous constants dynamically. This makes it easier to manage a growing number of templates, instead of going through TS strings. Includes a CI check to verify that any template changes are generated and committed.

• To keep thing simple we didn't add a separate folder for the ts router plugin router-plugin-ts, this will be done in a follow up pr, after everything is approved.

• The node health check package dynamically loads fs using an eval causing a null error when bundled with bun, it works when not bundled. https://github.com/protobufjs/protobuf.js/issues/997#issuecomment-3183117147, adds a workaround for now, to investigate further. We also used bun patch to override the internal __dirname because it is hardcoded to the directory the binary was compiled at on compile time (this especially breaks cosmo cloud plugins since the docker directory is temporary for building).

• Adds courses demo

Summary by CodeRabbit

• New Features

  • Multi-language plugin support: create, generate, test and build TypeScript (Bun) plugins alongside Go plugins with automatic language detection and appropriate templates.
  • New TypeScript plugin demo and project scaffolds included.

• Chores

  • Bun toolchain and CI setup added; template compilation and build scripts updated to support TS/Bun workflows.

Checklist

• [ ] I have discussed my proposed changes in an issue and have received approval to proceed.
• [ ] I have followed the coding standards of the project.
• [ ] Tests or benchmarks have been added or updated.
• [ ] Documentation has been updated on https://github.com/wundergraph/cosmo-docs.
• [ ] I have read the Contributors Guide.

[coderabbitai[bot]]

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Walkthrough

Adds language-aware plugin generation/build/test flows (Go and TypeScript/Bun), replaces single goModulePath with structured ProtoOption[] across proto generation, introduces many TS and Go templates, updates toolchain to be language-aware, adds template compiler and CI steps, and adds a demo Bun plugin with tests.

Changes

Cohort / File(s)	Summary
CLI plugin commands cli/src/commands/router/commands/plugin/commands/build.ts, cli/src/commands/router/commands/plugin/commands/generate.ts, cli/src/commands/router/commands/plugin/commands/init.ts, cli/src/commands/router/commands/plugin/commands/test.ts	Add language detection/guarding; branch flows for go vs ts; switch to ProtoOption[] for proto generation; update signatures, render contexts, and error handling.
Toolchain & runtime helpers cli/src/commands/router/commands/plugin/toolchain.ts	Large refactor: language-specific host/platform resolution and tool mappings; add getLanguage, validateAndGetGoModulePath, getGoModulePathProtoOption; add TS helpers (installTsDependencies, typeCheckTs, runTsTests, buildTsBinaries); rename buildBinaries → buildGoBinaries; propagate language and protoOptions.
Template compiler & packaging cli/scripts/compile-templates.ts, cli/package.json, .github/workflows/cli-ci.yaml	Add template compilation script, prebuild scripts to compile templates, and CI step to run template compilation.
Templates — core / export surface cli/src/commands/router/commands/plugin/templates/plugin.ts, cli/src/commands/router/commands/plugin/templates/project.ts, cli/src/commands/router/commands/plugin/templates/plugin/*, cli/src/commands/router/commands/plugin/templates/project/*	Restructure exported template keys (rename/remove/add entries: gitignore, makefile, cursorignore, readmePluginMd, schemaGraphql, graphYaml, routerConfigYaml, etc.).
Templates — Go cli/src/commands/router/commands/plugin/templates/go.ts, cli/src/commands/router/commands/plugin/templates/go/*	Add Go-specific templates: Dockerfile, go.mod.template, main.go.template, tests, README partials, cursor rules, and export surface for Go templates.
Templates — TypeScript / Bun cli/src/commands/router/commands/plugin/templates/typescript.ts, cli/src/commands/router/commands/plugin/templates/typescript/*	Add TS/Bun templates: package.json.template, plugin.ts.template, plugin-server.ts.template, tests, tsconfig, Dockerfile, debug/build scripts, health proto patch and protobufjs inquire patch.
Protobuf/GraphQL tooling (protographic) protographic/src/sdl-to-proto-visitor.ts, protographic/src/index.ts, protographic/tests/sdl-to-proto/*	Replace goPackage?: string with protoOptions?: ProtoOption[]; add exported ProtoOption type; emit proto options from protoOptions; update tests to new shape.
gRPC service codegen callsites cli/src/commands/grpc-service/commands/generate.ts	Build and pass ProtoOption[] (via getGoModulePathProtoOption) to compileGraphQLToProto instead of raw goPackage string.
Install tooling script scripts/install-proto-tools.sh	Add Bun/Node download/install helpers, bun/node platform mappings, and language-aware install flow with INSTALL_COMMON_TOOLS toggle.
CI/workflows & Makefiles .github/workflows/router-ci.yaml, .github/workflows/cli-ci.yaml, demo/Makefile	Add Bun setup step in router CI, template compile step in CLI CI, extend demo Makefile with Bun/Go build targets and integration copy steps.
Demo — Courses plugin (TS/Bun) demo/pkg/subgraphs/courses/*	Add new TypeScript/Bun demo plugin: package.json, tsconfig.json, schema.graphql, src/plugin.ts, src/plugin-server.ts, tests, patches, and integrate into demo graph/Makefile.
Router tests router-tests/router_plugin_test.go	Expand tests to cover courses plugin scenarios and additional request cases; add restart tests and split assertions for clarity.

Estimated code review effort

🎯 4 (Complex) | ⏱️ ~75 minutes

• Files/areas to focus on:
  • cli/src/commands/router/commands/plugin/toolchain.ts — platform mappings, language branching, tool install and version logic, and protoOptions propagation.
  • CLI command wiring (build.ts, generate.ts, init.ts, test.ts) — language detection, signature changes, and error short-circuits.
  • protographic/src/sdl-to-proto-visitor.ts and related exports/tests — correctness of emitted proto option lines and API compatibility.
  • Template compiler cli/scripts/compile-templates.ts and resulting template modules — property naming, escaping, and runtime expectations.
  • Demo Bun plugin, patches, and CI changes — build/test/runtime stability (Bun/Node integration).

Possibly related PRs

• wundergraph/cosmo#2079 — Implements similar multi-language plugin/toolchain and template scaffolding changes; likely touches the same CLI/toolchain surfaces.
• wundergraph/cosmo#2037 — Related changes to proto option handling in the SDL→proto visitor; overlaps with the protographic refactor to ProtoOption[].
• wundergraph/cosmo#2008 — Alters generateProtoAndMapping and proto-generation callsites; appears to modify the same function signature and related code paths.

Pre-merge checks and finishing touches

❌ Failed checks (1 warning)

Check name	Status	Explanation	Resolution
Docstring Coverage	⚠️ Warning	Docstring coverage is 69.44% which is insufficient. The required threshold is 80.00%.	You can run @coderabbitai generate docstrings to improve docstring coverage.

✅ Passed checks (2 passed)

Check name	Status	Explanation
Title check	✅ Passed	The title clearly and concisely describes the main feature being added: support for TypeScript and Bun-based gRPC plugins.
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.

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[github-actions[bot]]

Router image scan passed

:white_check_mark: No security vulnerabilities found in image:

ghcr.io/wundergraph/cosmo/router:sha-0798c30d4b8861887fe72a344d9e336ba5e14c60

[SkArchon]

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[SkArchon]

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[Noroth]

I don't see any integration tests in the router that call the Courses subgraph.

[SkArchon]

FYI: Discussed with Dustin that we only install tools specific per language (right now we install bun when using go plugins), will update and push soon

[SkArchon]

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