Initialize default reports directory only when needed (#1294)

`report` subcommand had some code to initialize its defaults for the
output directory. This code was executed during the initialization of
the subcommand, that is allways executed.

When running any command out of a package directory, this initialization
fails, as it depends on the package directory, and it produces an error
message.

Move this initialization to the code that gets the parameter in the
`report` subcommand, so it is only executed there, and only if the user
has not provided a value for the flag.

Author: jsoriano

cmd/report.go

@@ -18,7 +18,9 @@ import (
 	"github.com/elastic/elastic-package/internal/reportgenerator/outputs"
 )
 
-const reportLongDescription = `Use this command to generate various reports relative to the packages. Currently, the following types of reports are available:
+const (
+	benchmarksFolder      = "benchmark-report"
+	reportLongDescription = `Use this command to generate various reports relative to the packages. Currently, the following types of reports are available:
 
 #### Benchmark report for Github
 
@@ -27,6 +29,7 @@ The report will show performance differences between both runs.
 
 It is formatted as a Markdown Github comment to use as part of the CI results.
 `
+)
 
 func setupReportsCommand() *cobraext.Command {
 	var reportTypeCmdActions []cobraext.CommandAction
@@ -43,17 +46,13 @@ func setupReportsCommand() *cobraext.Command {
 			}
 
 			return cobraext.ComposeCommandActions(cmd, args, reportTypeCmdActions...)
-		}}
-
-	dest, err := resultsDir()
-	if err != nil {
-		cmd.PrintErrf("could not determine benchmark reports folder: %v", err)
+		},
 	}
 
 	cmd.PersistentFlags().BoolP(cobraext.FailOnMissingFlagName, "m", false, cobraext.FailOnMissingFlagDescription)
 	cmd.PersistentFlags().BoolP(cobraext.ReportFullFlagName, "", false, cobraext.ReportFullFlagDescription)
 	cmd.PersistentFlags().StringP(cobraext.ReportOutputFlagName, "", string(outputs.OutputFile), cobraext.ReportOutputFlagDescription)
-	cmd.PersistentFlags().StringP(cobraext.ReportOutputPathFlagName, "", dest, cobraext.ReportOutputPathFlagDescription)
+	cmd.PersistentFlags().StringP(cobraext.ReportOutputPathFlagName, "", "", fmt.Sprintf(cobraext.ReportOutputPathFlagDescription, benchmarksFolder))
 
 	// add benchmark report creation subcommand
 	cmd.AddCommand(getBenchReportCommand())
@@ -83,6 +82,13 @@ func getBenchReportCommand() *cobra.Command {
 			if err != nil {
 				return cobraext.FlagParsingError(err, cobraext.ReportOutputPathFlagName)
 			}
+			if reportOutputPath == "" {
+				dest, err := resultsDir()
+				if err != nil {
+					return fmt.Errorf("could not determine benchmark reports folder: %w", err)
+				}
+				reportOutputPath = dest
+			}
 
 			isFull, err := cmd.Flags().GetBool(cobraext.ReportFullFlagName)
 			if err != nil {
@@ -158,6 +164,5 @@ func resultsDir() (string, error) {
 	if err != nil {
 		return "", fmt.Errorf("locating build directory failed: %w", err)
 	}
-	const folder = "benchmark-report"
-	return filepath.Join(buildDir, folder), nil
+	return filepath.Join(buildDir, benchmarksFolder), nil
 }

internal/cobraext/flags.go

@@ -130,7 +130,7 @@ const (
 	ReportOutputFlagDescription = "output type for test report, eg: stdout, file"
 
 	ReportOutputPathFlagName        = "report-output-path"
-	ReportOutputPathFlagDescription = "output path for test report"
+	ReportOutputPathFlagDescription = "output path for test report (defaults to %q in build directory)"
 
 	ShowAllFlagName        = "all"
 	ShowAllFlagDescription = "show all deployed package revisions"