cleanup the "update" subcommand (dependabot#78)

Author: jakecoffman

README.md

@@ -39,7 +39,7 @@ Usage:
   dependabot [command]
 
 Examples:
-  $ dependabot update go_modules rsc/quote --dry-run
+  $ dependabot update go_modules rsc/quote
   $ dependabot test -f scenario.yaml
 
 Available Commands:
@@ -56,12 +56,11 @@ Use "dependabot [command] --help" for more information about a command.
 
 ### `dependabot update`
 
-Run the `update` subcommand with the `--dry-run` flag to
-simulate a Dependabot update job for the provided ecosystem and repo
-(without actually creating any PRs).
+Run the `update` subcommand to run a Dependabot update job for the provided ecosystem and repo.
+This does not create PRs, but outputs data that could be used to create PRs.
 
 ```console
-$ dependabot update go_modules rsc/quote --dry-run
+$ dependabot update go_modules rsc/quote
 # ...
 +----------------------------------------------------+
 |        Changes to Dependabot Pull Requests         |
@@ -103,7 +102,7 @@ using the `--file` / `-f` option
 (this replaces the package manager and repository name arguments).
 
 ```console
-dependabot update -f job.yaml --dry-run
+dependabot update -f job.yaml
 ```
 
 ```yaml
@@ -265,7 +264,7 @@ To produce a scenario file that tests Dependabot behavior for a given repo,
 run the `update` subcommand and set the `--output` / `-o` option to a file path.
 
 ```console
-dependabot update go_modules rsc/quote --dry-run -o go-scenario.yml
+dependabot update go_modules rsc/quote -o go-scenario.yml
 ```
 
 Run the `test` subcommand for the generated scenario file,

cmd/dependabot/internal/cmd/root.go

@@ -31,7 +31,7 @@ var rootCmd = &cobra.Command{
 	Short: "Dependabot end-to-end runner",
 	Long:  `Run Dependabot jobs from the command line.`,
 	Example: heredoc.Doc(`
-        $ dependabot update go_modules rsc/quote --dry-run
+        $ dependabot update go_modules rsc/quote
         $ dependabot test -f input.yml
 	`),
 	Version: Version(),

cmd/dependabot/internal/cmd/update.go

@@ -23,15 +23,14 @@ var (
 	repo           string
 	directory      string
 
-	dryRun          bool
 	inputServerPort int
 )
 
 var updateCmd = &cobra.Command{
 	Use:   "update <package_manager> <repo> [flags]",
-	Short: "Perform update job",
+	Short: "Perform an update job",
 	Example: heredoc.Doc(`
-		    $ dependabot update go_modules rsc/quote --dry-run
+		    $ dependabot update go_modules rsc/quote
 	    `),
 	RunE: func(cmd *cobra.Command, args []string) error {
 		var outFile *os.File
@@ -213,10 +212,9 @@ func processInput(input *model.Input) {
 }
 
 func doesStdinHaveData() bool {
-	file := os.Stdin
-	fi, err := file.Stat()
+	fi, err := os.Stdin.Stat()
 	if err != nil {
-		fmt.Println("file.Stat()", err)
+		log.Println("file.Stat()", err)
 	}
 	return fi.Size() > 0
 }
@@ -229,9 +227,6 @@ func init() {
 	updateCmd.Flags().StringVarP(&provider, "provider", "p", "github", "provider of the repository")
 	updateCmd.Flags().StringVarP(&directory, "directory", "d", "/", "directory to update")
 
-	updateCmd.Flags().BoolVar(&dryRun, "dry-run", true, "perform update as a dry run")
-	_ = updateCmd.MarkFlagRequired("dry-run")
-
 	updateCmd.Flags().StringVarP(&output, "output", "o", "", "write scenario to file")
 	updateCmd.Flags().StringVar(&cache, "cache", "", "cache import/export directory")
 	updateCmd.Flags().StringVar(&proxyCertPath, "proxy-cert", "", "path to a certificate the proxy will trust")

docs/debugging.md

@@ -4,11 +4,11 @@ This guide will help you debug issues with your Dependabot update using the Depe
 
 ## Getting started
 
-First, test to make sure you have a working Dependabot CLI by performing a simple update, like `dependabot update --dry-run go_modules rsc/quote -o out.yml`. This should complete without error, and you can examine the out.yml file which should contain two calls to `create_pull_request`.
+First, test to make sure you have a working Dependabot CLI by performing a simple update, like `dependabot update go_modules rsc/quote -o out.yml`. This should complete without error, and you can examine the out.yml file which should contain two calls to `create_pull_request`.
 
 Next, clone https://github.com/dependabot/dependabot-core. This project contains all the source for the updater images, and a helpful script `script/dependabot` which will mount the ecosystems in the container that the CLI starts.
 
-Try opening a terminal and run `script/dependabot update --dry-run go_modules rsc/quote --debug` in the `dependabot-core` project directory. This will drop you in an interactive session with the update ready to proceed.
+Try opening a terminal and run `script/dependabot update go_modules rsc/quote --debug` in the `dependabot-core` project directory. This will drop you in an interactive session with the update ready to proceed.
 
 To perform the update, you need to run two commands:
 
@@ -60,7 +60,7 @@ At this prompt, you can run [debugger commands](https://github.com/ruby/debug) t
 
 If your Dependabot job is hanging and would like to figure out why, the CLI is the perfect tool for the job. 
 
-Start by running the update that recreates the hang with `dependabot update --dry-run <ecosystem> <org/repo>`. Once the hang is reproducible, run with the `--debug` flag and the run the `fetch_files` and `update_files` commands and wait until the job hangs.
+Start by running the update that recreates the hang with `dependabot update <ecosystem> <org/repo>`. Once the hang is reproducible, run with the `--debug` flag and the run the `fetch_files` and `update_files` commands and wait until the job hangs.
 
 Once it does hang, hit CTL-C, and you'll get a stack trace leading you to the problematic code.
 

internal/server/api.go

@@ -122,10 +122,13 @@ func (a *API) ServeHTTP(_ http.ResponseWriter, r *http.Request) {
 	}
 
 	if !a.hasExpectations {
-		// When running an update, there's no way to see the error in the record_update_job_error,
-		// but it's handy to see it in the logs for debugging.
-		if kind == "record_update_job_error" {
-			log.Println("update-job error:", actual.Data)
+		// output the data received to stdout
+		if err = json.NewEncoder(os.Stdout).Encode(map[string]any{
+			"type": kind,
+			"data": actual.Data,
+		}); err != nil {
+			// Fail so the user knows stdout is not working
+			log.Panicln("Failed to write to stdout: ", err)
 		}
 		return
 	}