Add ignore-already-exists flag to skip chartmuseum 409 error

Author: alexandrevilain

README.md

@@ -67,6 +67,14 @@ Pushing mychart-0.3.2.tgz to chartmuseum...
 Done.
 ```
 
+If the `--force`/`-f` option is not set and the chart already exists you will get an error:
+```
+$ helm push mychart/ chartmuseum
+Pushing mychart-0.1.0.tgz to chartmuseum...
+Error: 409: mychart-0.1.0.tgz already exists
+```
+For some environnements, like in CI/CD pipelines, this error should not stop the whole pipeline and can be skipped using the `--ignore-already-exists` option.
+
 ### Pushing directly to URL
 If the second argument provided resembles a URL, you are not required to add the repo prior to push:
 ```

cmd/helmpush/main.go

@@ -40,6 +40,7 @@ type (
 		authHeader         string
 		contextPath        string
 		forceUpload        bool
+		ignoreAlreadyExistsError bool
 		useHTTP            bool
 		checkHelmVersion   bool
 		caFile             string
@@ -121,6 +122,7 @@ func newPushCmd(args []string) *cobra.Command {
 	f.StringVar(&p.keyring, "keyring", defaultKeyring(), "location of a public keyring")
 	f.BoolVarP(&p.insecureSkipVerify, "insecure", "", false, "Connect to server with an insecure way by skipping certificate verification [$HELM_REPO_INSECURE]")
 	f.BoolVarP(&p.forceUpload, "force", "f", false, "Force upload even if chart version exists")
+	f.BoolVarP(&p.ignoreAlreadyExistsError, "ignore-already-exists", "", false, "Skip the already exisits error if chart version exists")
 	f.BoolVarP(&p.dependencyUpdate, "dependency-update", "d", false, `update dependencies from "requirements.yaml" to dir "charts/" before packaging`)
 	f.BoolVarP(&p.checkHelmVersion, "check-helm-version", "", false, `outputs either "2" or "3" indicating the current Helm major version`)
 
@@ -328,7 +330,7 @@ func (p *pushCmd) push() error {
 		return err
 	}
 
-	return handlePushResponse(resp)
+	return p.handlePushResponse(resp)
 }
 
 func (p *pushCmd) download(fileURL string) error {
@@ -384,13 +386,18 @@ func (p *pushCmd) download(fileURL string) error {
 	return handleDownloadResponse(resp)
 }
 
-func handlePushResponse(resp *http.Response) error {
+func (p *pushCmd) handlePushResponse(resp *http.Response) error {
 	if resp.StatusCode != 201 {
 		b, err := ioutil.ReadAll(resp.Body)
 		if err != nil {
 			return err
 		}
-		return getChartmuseumError(b, resp.StatusCode)
+		err = getChartmuseumError(b, resp.StatusCode)
+		if p.ignoreAlreadyExistsError && resp.StatusCode == 409 {
+			fmt.Printf("Got the following error: %s \nSkipping.\n", err)
+			return nil
+		}
+		return err
 	}
 	fmt.Println("Done.")
 	return nil