silo-plugin-sdk

Public Go SDK for building Silo plugins. Not a runtime plugin — this is a library that plugin authors depend on via go.mod.

silo-plugin-sdk is the source of truth for the plugin authoring contract. First-party consumers (Silo host, silo-plugin-tmdb, silo-plugin-metadb, every other plugin in this repo) pin tagged semver releases. Local multi-repo workspaces may use go.work or a temporary replace, but CI and release builds resolve the SDK from a published module tag.

Packages

• github.com/Silo-Server/silo-plugin-sdk/pkg/pluginproto/silo/plugin/v1 — generated protobuf code.
• github.com/Silo-Server/silo-plugin-sdk/pkg/pluginsdk/capability — stable capability type constants for manifests and peer discovery.
• github.com/Silo-Server/silo-plugin-sdk/pkg/pluginsdk/config — config-schema helpers.
• github.com/Silo-Server/silo-plugin-sdk/pkg/pluginsdk/convert — type conversions.
• github.com/Silo-Server/silo-plugin-sdk/pkg/pluginsdk/manifest — manifest loading/rendering.
• github.com/Silo-Server/silo-plugin-sdk/pkg/pluginsdk/runtime — manifest subcommand + Runtime server scaffolding.
• github.com/Silo-Server/silo-plugin-sdk/pkg/pluginsdk/runtimedefault — default Runtime implementation with BindHostBroker already wired; embed it to skip boilerplate.
• github.com/Silo-Server/silo-plugin-sdk/pkg/pluginsdk/runtimehost — typed client for the host's RuntimeHost service, including event publishing, host info, catalog browsing, installed-plugin discovery, scoped streams, plugin-to-plugin HTTP calls, and plugin-owned config writes.

Capability families

The SDK ships protobuf contracts for every capability the host understands:

• metadata_provider.v1
• media_analyzer.v1
• scheduled_task.v1
• event_consumer.v1
• auth_provider.v1
• http_routes.v1
• request_router.v1
• audiobook_backend.v1
• ebook_backend.v1

Plugins implement one or more, advertise them in manifest.json, and serve them over gRPC.

Author workflow

A typical plugin:

1. Defines a manifest.json using the protobuf-derived schema.
2. Exposes a Runtime gRPC server plus one or more capability servers.
3. Supports the manifest subcommand via pkg/pluginsdk/runtime so the host can introspect manifests without launching the plugin.
4. Is installed either from a catalog or by uploading a trusted binary to a Silo server.

For a minimal self-describing plugin, see examples/hello-scheduled-task. For a plugin that calls back into the host via RuntimeHost (publishing events, listing libraries), see examples/hello-runtime-host.

Calling back into the host

Plugins talk to the host through the RuntimeHost service, accessed via pkg/pluginsdk/runtimehost.Client. The host invokes Runtime.BindHostBroker on startup so plugins can dial back over the shared broker; runtimedefault handles that step for you. Available RPCs:

• PublishEvent / PublishEventTo / PublishEventToInstallation — fire events into the host's bus, broadcast, addressed to a stable plugin_id, or addressed to one specific installation.
• GetHostInfo — read host URL metadata for callback URLs and external-facing plugin links.
• ListLibraries — enumerate libraries the operator has configured.
• CheckMediaPresence — ask whether a given external id is already in the catalog.
• ListInstalledPlugins — discover sibling plugins (e.g. routers a request plugin can target).
• ListLibraryMedia / GetCatalogStats — read public-safe catalog rows and aggregate counts.
• ResolveCatalogImageURLs — resolve stored poster/backdrop image paths into host-generated browser URLs.
• MintScopedStream — create short-lived, narrowly scoped stream grants for guest/public workflows.
• CallPluginHTTP — invoke another installed plugin's http_routes.v1 handler through the host control plane.
• SetGlobalConfigEntry — persist plugin-owned config that admins didn't set via the manifest form.

For plugin-to-plugin JSON calls, prefer the helper layer:

plugins, err := host.ListInstalledPluginsByCapability(ctx, capability.RequestRouter)
if err != nil || len(plugins) == 0 {
    return err
}

var out struct {
    Accepted bool `json:"accepted"`
}
err = host.CallPluginJSON(ctx, runtimehost.CallPluginJSONRequest{
    InstallationID: int(plugins[0].GetInstallationId()),
    Path:           "/api/request",
    Request:        map[string]any{"title": "The Matrix"},
    Response:       &out,
})

The auth_provider.v1 capability also exposes OAuth-flow RPCs (InitAuthorize, ExchangeCode, RefreshSession) for plugins that wrap external identity providers.

Self-describing binaries

Direct binary upload works best when the plugin embeds a manifest template and computes its own executable checksum at runtime before returning Runtime.GetManifest. That keeps the plugin installable without requiring a checked-out Silo repository or a sibling manifest.json file at upload time. The example plugin shows the pattern.

Compatibility

Compatibility and versioning expectations are documented in docs/compatibility.md.

Releases

SDK releases are cut from semver tags such as v0.1.0 and published through GitHub Actions.

• Additive public API changes belong in a new minor release.
• Compatible fixes and documentation updates belong in a patch release.
• Breaking public API, protobuf, or manifest contract changes require a new major version.

Before downstream repos stop using local workspace overrides, the required SDK commit must be pushed and tagged here first.

Build & test

make proto       # regenerate protobuf code (uses locally vendored buf under ./bin/)
go test ./...

License

Apache-2.0. See LICENSE.