feat: add --output-document flag to the export CLI command to allow writing genesis state to a file instead of STDOUT

CHANGELOG.md

@@ -87,6 +87,7 @@ Ref: https://keepachangelog.com/en/1.0.0/
 * [#13651](https://github.com/cosmos/cosmos-sdk/pull/13651) Update `server/config/config.GetConfig` function.
 * [#13781](https://github.com/cosmos/cosmos-sdk/pull/13781) Remove `client/keys.KeysCdc`.
 * [#13803](https://github.com/cosmos/cosmos-sdk/pull/13803) Add an error log if iavl set operation failed.
+* [#13802](https://github.com/cosmos/cosmos-sdk/pull/13802) Add --output-document flag to the export CLI command to allow writing genesis state to a file.
 
 ### State Machine Breaking
 

server/export.go

@@ -20,6 +20,7 @@ const (
 	FlagForZeroHeight    = "for-zero-height"
 	FlagJailAllowedAddrs = "jail-allowed-addrs"
 	FlagModulesToExport  = "modules-to-export"
+	FlagOutputDocument   = "output-document"
 )
 
 // ExportCmd dumps app state to JSON.
@@ -67,6 +68,7 @@ func ExportCmd(appExporter types.AppExporter, defaultNodeHome string) *cobra.Com
 			forZeroHeight, _ := cmd.Flags().GetBool(FlagForZeroHeight)
 			jailAllowedAddrs, _ := cmd.Flags().GetStringSlice(FlagJailAllowedAddrs)
 			modulesToExport, _ := cmd.Flags().GetStringSlice(FlagModulesToExport)
+			outputDocument, _ := cmd.Flags().GetString(FlagOutputDocument)
 
 			exported, err := appExporter(serverCtx.Logger, db, traceWriter, height, forZeroHeight, jailAllowedAddrs, serverCtx.Viper, modulesToExport)
 			if err != nil {
@@ -106,7 +108,21 @@ func ExportCmd(appExporter types.AppExporter, defaultNodeHome string) *cobra.Com
 
 			cmd.SetOut(cmd.OutOrStdout())
 			cmd.SetErr(cmd.OutOrStderr())
-			cmd.Println(string(sdk.MustSortJSON(encoded)))
+			out := sdk.MustSortJSON(encoded)
+
+			if outputDocument == "" {
+				cmd.Println(string(out))
+				return nil
+			}
+
+			var exportedGenDoc tmtypes.GenesisDoc
+			if err = tmjson.Unmarshal(out, &exportedGenDoc); err != nil {
+				return err
+			}
+			if err = exportedGenDoc.SaveAs(outputDocument); err != nil {
+				return err
+			}
+
 			return nil
 		},
 	}
@@ -116,6 +132,7 @@ func ExportCmd(appExporter types.AppExporter, defaultNodeHome string) *cobra.Com
 	cmd.Flags().Bool(FlagForZeroHeight, false, "Export state to start at height zero (perform preproccessing)")
 	cmd.Flags().StringSlice(FlagJailAllowedAddrs, []string{}, "Comma-separated list of operator addresses of jailed validators to unjail")
 	cmd.Flags().StringSlice(FlagModulesToExport, []string{}, "Comma-separated list of modules to export. If empty, will export all modules")
+	cmd.Flags().String(FlagOutputDocument, "", "Exported state is written to the given file instead of STDOUT")
 
 	return cmd
 }

tests/e2e/server/export_test.go

@@ -122,6 +122,47 @@ func TestExportCmd_Height(t *testing.T) {
 	}
 }
 
+func TestExportCmd_Output(t *testing.T) {
+	testCases := []struct {
+		name           string
+		flags          []string
+		outputDocument string
+	}{
+		{
+			"should export state to the specified file",
+			[]string{
+				fmt.Sprintf("--%s=%s", server.FlagOutputDocument, "foobar.json"),
+			},
+			"foobar.json",
+		},
+	}
+
+	for _, tc := range testCases {
+		t.Run(tc.name, func(t *testing.T) {
+			tempDir := t.TempDir()
+			_, ctx, _, cmd := setupApp(t, tempDir)
+
+			output := &bytes.Buffer{}
+			cmd.SetOut(output)
+			args := append(tc.flags, fmt.Sprintf("--%s=%s", flags.FlagHome, tempDir))
+			cmd.SetArgs(args)
+			require.NoError(t, cmd.ExecuteContext(ctx))
+
+			var exportedGenDoc tmtypes.GenesisDoc
+			f, err := os.ReadFile(tc.outputDocument)
+			if err != nil {
+				t.Fatalf("error reading exported genesis doc: %s", err)
+			}
+			require.NoError(t, tmjson.Unmarshal(f, &exportedGenDoc))
+
+			// Cleanup
+			if err = os.Remove(tc.outputDocument); err != nil {
+				t.Fatalf("error removing exported genesis doc: %s", err)
+			}
+		})
+	}
+}
+
 func setupApp(t *testing.T, tempDir string) (*simapp.SimApp, context.Context, *tmtypes.GenesisDoc, *cobra.Command) {
 	t.Helper()