helm/docs/chart_repository_sync_example.md

# Syncing Your Chart Repository
*Note: This example is specifically for a Google Cloud Storage (GCS) bucket which serves a chart repository.*

## Prerequisites
* Install the [gsutil](https://cloud.google.com/storage/docs/gsutil) tool. *We rely heavily on the gsutil rsync functionality*
* Be sure to have access to the Helm binary
* _Optional: We recommend you set [object versioning](https://cloud.google.com/storage/docs/gsutil/addlhelp/ObjectVersioningandConcurrencyControl#top_of_page) on your GCS bucket in case you accidentally delete something._

## Set up a local chart repository directory
Create a local directory like we did in [the chart repository guide](chart_repository.md), and place your packaged charts in that directory.

For example:
```console
$ mkdir fantastic-charts
$ mv alpine-0.1.0.tgz fantastic-charts/
```

## Generate an updated index.yaml
Use Helm to generate an updated index.yaml file by passing in the directory path and the url of the remote repository to the `helm repo index` command like this:

```console
$ helm repo index fantastic-charts/ --url https://fantastic-charts.storage.googleapis.com
```
This will generate an updated index.yaml file and place in the `fantastic-charts/` directory.

## Sync your local and remote chart repositories
Upload the contents of the directory to your GCS bucket by running `scripts/sync-repo.sh` and pass in the local directory name and the GCS bucket name.

For example:
```console
$ pwd
/Users/funuser/go/src/github.com/kubernetes/helm
$ scripts/sync-repo.sh fantastic-charts/ fantastic-charts
Getting ready to sync your local directory (fantastic-charts/) to a remote repository at gs://fantastic-charts
Verifying Prerequisites....
Thumbs up! Looks like you have gsutil. Let's continue.
Building synchronization state...
Starting synchronization
Would copy file://fantastic-charts/alpine-0.1.0.tgz to gs://fantastic-charts/alpine-0.1.0.tgz
Would copy file://fantastic-charts/index.yaml to gs://fantastic-charts/index.yaml
Are you sure you would like to continue with these changes?? [y/N]} y
Building synchronization state...
Starting synchronization
Copying file://fantastic-charts/alpine-0.1.0.tgz [Content-Type=application/x-tar]...
Uploading   gs://fantastic-charts/alpine-0.1.0.tgz:              740 B/740 B
Copying file://fantastic-charts/index.yaml [Content-Type=application/octet-stream]...
Uploading   gs://fantastic-charts/index.yaml:                    347 B/347 B
Congratulations your remote chart repository now matches the contents of fantastic-charts/
```
## Updating your chart repository
You'll want to keep a local copy of the contents of your chart repository or use `gsutil rsync` to copy the contents of your remote chart repository to a local directory.

For example:
```console
$ gsutil rsync -d -n gs://bucket-name local-dir/    # the -n flag does a dry run
Building synchronization state...
Starting synchronization
Would copy gs://bucket-name/alpine-0.1.0.tgz to file://local-dir/alpine-0.1.0.tgz
Would copy gs://bucket-name/index.yaml to file://local-dir/index.yaml

$ gsutil rsync -d gs://bucket-name local-dir/       # performs the copy actions
Building synchronization state...
Starting synchronization
Copying gs://bucket-name/alpine-0.1.0.tgz...
Downloading file://local-dir/alpine-0.1.0.tgz:                        740 B/740 B
Copying gs://bucket-name/index.yaml...
Downloading file://local-dir/index.yaml:                              346 B/346 B
```


Helpful Links:
* Documentation on [gsutil rsync](https://cloud.google.com/storage/docs/gsutil/commands/rsync#description)
* [The Chart Repository Guide](chart_repository.md)
* Documentation on [object versioning and concurrency control](https://cloud.google.com/storage/docs/gsutil/addlhelp/ObjectVersioningandConcurrencyControl#overview) in Google Cloud Storage