Plugins: Transform plugin support (#20036)

currently temporary separate http api

pkg/plugins/backendplugin/client.go

@@ -0,0 +1,81 @@
+package backendplugin
+
+import (
+	"os/exec"
+
+	"github.com/grafana/grafana/pkg/infra/log"
+
+	datasourceV1 "github.com/grafana/grafana-plugin-model/go/datasource"
+	rendererV1 "github.com/grafana/grafana-plugin-model/go/renderer"
+	sdk "github.com/grafana/grafana-plugin-sdk-go/common"
+	datasourceV2 "github.com/grafana/grafana-plugin-sdk-go/datasource"
+	transformV2 "github.com/grafana/grafana-plugin-sdk-go/transform"
+	"github.com/hashicorp/go-plugin"
+)
+
+const (
+	// DefaultProtocolVersion is the protocol version assumed for legacy clients that don't specify
+	// a particular version or version 1 during their handshake. This is currently the version used
+	// since Grafana launched support for backend plugins.
+	DefaultProtocolVersion = 1
+)
+
+// Handshake is the HandshakeConfig used to configure clients and servers.
+var handshake = plugin.HandshakeConfig{
+	// The ProtocolVersion is the version that must match between Grafana core
+	// and Grafana plugins. This should be bumped whenever a (breaking) change
+	// happens in one or the other that makes it so that they can't safely communicate.
+	ProtocolVersion: DefaultProtocolVersion,
+
+	// The magic cookie values should NEVER be changed.
+	MagicCookieKey:   sdk.MagicCookieKey,
+	MagicCookieValue: sdk.MagicCookieValue,
+}
+
+// NewClientConfig returns a configuration object that can be used to instantiate
+// a client for the plugin described by the given metadata.
+func NewClientConfig(executablePath string, logger log.Logger, versionedPlugins map[int]plugin.PluginSet) *plugin.ClientConfig {
+	return &plugin.ClientConfig{
+		Cmd:              exec.Command(executablePath),
+		HandshakeConfig:  handshake,
+		VersionedPlugins: versionedPlugins,
+		Logger:           logWrapper{Logger: logger},
+		AllowedProtocols: []plugin.Protocol{plugin.ProtocolGRPC},
+	}
+}
+
+// NewDatasourceClient returns a datasource plugin client.
+func NewDatasourceClient(pluginID, executablePath string, logger log.Logger) *plugin.Client {
+	versionedPlugins := map[int]plugin.PluginSet{
+		1: {
+			pluginID: &datasourceV1.DatasourcePluginImpl{},
+		},
+		2: {
+			pluginID: &datasourceV2.DatasourcePluginImpl{},
+		},
+	}
+
+	return plugin.NewClient(NewClientConfig(executablePath, logger, versionedPlugins))
+}
+
+// NewRendererClient returns a renderer plugin client.
+func NewRendererClient(pluginID, executablePath string, logger log.Logger) *plugin.Client {
+	versionedPlugins := map[int]plugin.PluginSet{
+		1: {
+			pluginID: &rendererV1.RendererPluginImpl{},
+		},
+	}
+
+	return plugin.NewClient(NewClientConfig(executablePath, logger, versionedPlugins))
+}
+
+// NewTransformClient returns a transform plugin client.
+func NewTransformClient(pluginID, executablePath string, logger log.Logger) *plugin.Client {
+	versionedPlugins := map[int]plugin.PluginSet{
+		2: {
+			pluginID: &transformV2.TransformPluginImpl{},
+		},
+	}
+
+	return plugin.NewClient(NewClientConfig(executablePath, logger, versionedPlugins))
+}