feat: Add means to fetch schema

cli/cli.go

@@ -59,6 +59,7 @@ func NewDefraCommand(cfg *config.Config) *cobra.Command {
 		MakeSchemaAddCommand(),
 		MakeSchemaPatchCommand(),
 		MakeSchemaSetDefaultCommand(),
+		MakeSchemaDescribeCommand(),
 		schema_migrate,
 	)
 

cli/schema_describe.go

@@ -0,0 +1,82 @@
+// Copyright 2023 Democratized Data Foundation
+//
+// Use of this software is governed by the Business Source License
+// included in the file licenses/BSL.txt.
+//
+// As of the Change Date specified in that file, in accordance with
+// the Business Source License, use of this software will be governed
+// by the Apache License, Version 2.0, included in the file
+// licenses/APL.txt.
+
+package cli
+
+import (
+	"github.com/spf13/cobra"
+
+	"github.com/sourcenetwork/defradb/client"
+)
+
+func MakeSchemaDescribeCommand() *cobra.Command {
+	var name string
+	var root string
+	var versionID string
+
+	var cmd = &cobra.Command{
+		Use:   "describe",
+		Short: "View schema descriptions.",
+		Long: `Introspect schema types.
+
+Example: view all schemas
+  defradb client schema describe
+
+Example: view schemas by name
+  defradb client schema describe --name User
+
+Example: view schemas by root
+  defradb client schema describe --root bae123
+
+Example: view a single schema by version id
+  defradb client schema describe --version bae123
+		`,
+		RunE: func(cmd *cobra.Command, args []string) error {
+			store := mustGetStoreContext(cmd)
+
+			var schemas []client.SchemaDescription
+			switch {
+			case versionID != "":
+				schema, err := store.GetSchemaByVersionID(cmd.Context(), versionID)
+				if err != nil {
+					return err
+				}
+				return writeJSON(cmd, schema)
+
+			case root != "":
+				s, err := store.GetSchemasByRoot(cmd.Context(), root)
+				if err != nil {
+					return err
+				}
+				schemas = s
+
+			case name != "":
+				s, err := store.GetSchemasByName(cmd.Context(), name)
+				if err != nil {
+					return err
+				}
+				schemas = s
+
+			default:
+				s, err := store.GetAllSchemas(cmd.Context())
+				if err != nil {
+					return err
+				}
+				schemas = s
+			}
+
+			return writeJSON(cmd, schemas)
+		},
+	}
+	cmd.PersistentFlags().StringVar(&name, "name", "", "Schema name")
+	cmd.PersistentFlags().StringVar(&root, "root", "", "Schema root")
+	cmd.PersistentFlags().StringVar(&versionID, "version", "", "Schema Version ID")
+	return cmd
+}

client/db.go

@@ -161,6 +161,22 @@ type Store interface {
 	// this [Store].
 	GetAllCollections(context.Context) ([]Collection, error)
 
+	// GetSchemasByName returns the all schema versions with the given name.
+	GetSchemasByName(context.Context, string) ([]SchemaDescription, error)
+
+	// GetSchemaByVersionID returns the schema description for the schema version of the
+	// ID provided.
+	//
+	// Will return an error if it is not found.
+	GetSchemaByVersionID(context.Context, string) (SchemaDescription, error)
+
+	// GetSchemasByRoot returns the all schema versions for the given root.
+	GetSchemasByRoot(context.Context, string) ([]SchemaDescription, error)
+
+	// GetAllSchemas returns all schema versions that currently exist within
+	// this [Store].
+	GetAllSchemas(context.Context) ([]SchemaDescription, error)
+
 	// GetAllIndexes returns all the indexes that currently exist within this [Store].
 	GetAllIndexes(context.Context) (map[CollectionName][]IndexDescription, error)