# Git Repository Contents

Fleet will create bundles from a git repository. This happens either explicitly by specifying paths, or when a `fleet.yaml` is found.

Each bundle is created from paths in a GitRepo and modified further by reading the discovered `fleet.yaml` file.
Bundle lifecycles are tracked between releases by the helm releaseName field added to each bundle. If the releaseName is not
specified within fleet.yaml it is generated from `GitRepo.name + path`. Long names are truncated and a `-<hash>` prefix is added.

**The git repository has no explicitly required structure.** It is important
to realize the scanned resources will be saved as a resource in Kubernetes so
you want to make sure the directories you are scanning in git do not contain
arbitrarily large resources. Right now there is a limitation that the resources
deployed must **gzip to less than 1MB**.

## How repos are scanned

Multiple paths can be defined for a `GitRepo` and each path is scanned independently.
Internally each scanned path will become a [bundle](./concepts.md) that Fleet will manage,
deploy, and monitor independently.

The following files are looked for to determine the how the resources will be deployed.

| File | Location | Meaning |
|------|----------|---------|
| **Chart.yaml**:| / relative to `path` or custom path from `fleet.yaml` | The resources will be deployed as a Helm chart. Refer to the `fleet.yaml` for more options. |
| **kustomization.yaml**:| / relative to `path` or custom path from `fleet.yaml` | The resources will be deployed using Kustomize. Refer to the `fleet.yaml` for more options. |
| **fleet.yaml** | Any subpath | If any fleet.yaml is found a new [bundle](./concepts.md) will be defined. This allows mixing charts, kustomize, and raw YAML in the same repo |
| ** *.yaml ** | Any subpath | If a `Chart.yaml` or `kustomization.yaml` is not found then any `.yaml` or `.yml` file will be assumed to be a Kubernetes resource and will be deployed. |
| **overlays/{name}** | / relative to `path` | When deploying using raw YAML (not Kustomize or Helm) `overlays` is a special directory for customizations. |

### Excluding files and directories from bundles

Fleet supports file and directory exclusion by means of `.fleetignore` files, in a similar fashion to how `.gitignore`
files behave in git repositories:
* Glob syntax is used to match files or directories, using Golang's
  [`filepath.Match`](https://pkg.go.dev/path/filepath#Match)
* Empty lines are skipped, and can therefore be used to improve readability
* Characters like white spaces and `#` can be escaped with a backslash
* Trailing spaces are ignored, unless escaped
* Comments, ie lines starting with unescaped `#`, are skipped
* A given line can match a file or a directory, even if no separator is provided: eg. `subdir/*` and `subdir` are both
  valid `.fleetignore` lines, and `subdir` matches both files and directories called `subdir`
* A match may be found for a file or directory at any level below the directory where a `.fleetignore` lives, ie
  `foo.yaml` will match `./foo.yaml` as well as `./path/to/foo.yaml`
* Multiple `.fleetignore` files are supported. For instance, in the following directory structure, only
  `root/something.yaml`, `bar/something2.yaml` and `foo/something.yaml` will end up in a bundle:
```
root/
├── .fleetignore            # contains `ignore-always.yaml'
├── something.yaml
├── bar
│   ├── .fleetignore        # contains `something.yaml`
│   ├── ignore-always.yaml
│   ├── something2.yaml
│   └── something.yaml
└── foo
    ├── ignore-always.yaml
    └── something.yaml
```

This currently comes with a few limitations, the following not being supported:
* Double asterisks (`**`)
* Explicit inclusions with `!`

## `fleet.yaml`

The `fleet.yaml` is an optional file that can be included in the git repository to change the behavior of how
the resources are deployed and customized.  The `fleet.yaml` is always at the root relative to the `path` of the `GitRepo`
and if a subdirectory is found with a `fleet.yaml` a new [bundle](./concepts.md) is defined that will then be
configured differently from the parent bundle.

:::caution

__Helm chart dependencies__:
It is up to the user to fulfill the dependency list for the Helm charts. As such, you must manually run `helm dependencies update $chart` OR run `helm dependencies build $chart` prior to install. See the [Fleet docs](https://rancher.com/docs/rancher/v2.6/en/deploy-across-clusters/fleet/#helm-chart-dependencies) in Rancher for more information.

:::

The available fields are documented in the [fleet.yaml reference](./ref-fleet-yaml.md)

For a private Helm repo, users can reference a secret from the git repo resource.
See [Using Private Helm Repositories](./gitrepo-add.md#using-private-helm-repositories) for more information.

## Using Helm Values

__How changes are applied to `values.yaml`__:

- Note that the most recently applied changes to the `values.yaml` will override any previously existing values.

- When changes are applied to the `values.yaml` from multiple sources at the same time, the values will update in the following order: `helm.values` -> `helm.valuesFiles` -> `helm.valuesFrom`. That means `valuesFrom` will take precedence over both, `valuesFiles` and `values`.

### Using ValuesFrom

These examples showcase the style and format for using `valuesFrom`. ConfigMaps and Secrets should be created in *downstream clusters*.

Example [ConfigMap](https://kubernetes.io/docs/concepts/configuration/configmap/):

```yaml
apiVersion: v1
kind: ConfigMap
metadata:
  name: configmap-values
  namespace: default
data:
  values.yaml: |-
    replication: true
    replicas: 2
    serviceType: NodePort
```

Example [Secret](https://kubernetes.io/docs/concepts/configuration/secret/):

```yaml
apiVersion: v1
kind: Secret
metadata:
  name: secret-values
  namespace: default
stringData:
  values.yaml: |-
    replication: true
    replicas: 3
    serviceType: NodePort
```

A secret like that, can be created from a YAML file `secretdata.yaml` by running the following kubectl command: `kubectl create secret generic secret-values --from-file=values.yaml=secretdata.yaml`

The resources can then be referenced from a `fleet.yaml`:

```yaml
helm:
  chart: simple-chart
  valuesFrom:
    - secretKeyRef:
        name: secret-values
        namespace: default
        key: values.yaml
    - configMapKeyRef:
        name: configmap-values
        namespace: default
        key: values.yaml
  values:
    replicas: "4"
```

## Per Cluster Customization

The `GitRepo` defines which clusters a git repository should be deployed to and the `fleet.yaml` in the repository
determines how the resources are customized per target.

All clusters and cluster groups in the same namespace as the `GitRepo` will be evaluated against all targets of that
`GitRepo`. The targets list is evaluated one by one and if there is a match the resource will be deployed to the cluster.
If no match is made against the target list on the `GitRepo` then the resources will not be deployed to that cluster.
Once a target cluster is matched the `fleet.yaml` from the git repository is then consulted for customizations. The
`targetCustomizations` in the `fleet.yaml` will be evaluated one by one and the first match will define how the
resource is to be configured. If no match is made the resources will be deployed with no additional customizations.

There are three approaches to matching clusters for both `GitRepo` `targets` and `fleet.yaml` `targetCustomizations`.
One can use cluster selectors, cluster group selectors, or an explicit cluster group name.  All criteria is additive so
the final match is evaluated as "clusterSelector && clusterGroupSelector && clusterGroup".  If any of the three have the
default value it is dropped from the criteria.  The default value is either null or "".  It is important to realize
that the value `{}` for a selector means "match everything."

```yaml
targetCustomizations:
- name: all
  # Match everything
  clusterSelector: {}
- name: none
  # Selector ignored
  clusterSelector: null
```

When matching a cluster by name, make sure to use the name of the
`clusters.fleet.cattle.io` resource. The Rancher UI also has a provisioning and
a management cluster resource. Since the management cluster resource is not
namespaced, its name is different and contains a random suffix.

```yaml
targetCustomizations:
- name: prod
  clusterName: fleetname
```

See [Mapping to Downstream Clusters](gitrepo-targets#customization-per-cluster) for more information and a list of supported customizations.

## Raw YAML Resource Customization

When using Kustomize or Helm the `kustomization.yaml` or the `helm.values` will control how the resource are
customized per target cluster. If you are using raw YAML then the following simple mechanism is built-in and can
be used.  The `overlays/` folder in the git repo is treated specially as folder containing folders that
can be selected to overlay on top per target cluster. The resource overlay content
uses a file name based approach.  This is different from kustomize which uses a resource based approach.  In kustomize
the resource Group, Kind, Version, Name, and Namespace identify resources and are then merged or patched.  For Fleet
the overlay resources will override or patch content with a matching file name.

```shell
# Base files
deployment.yaml
svc.yaml

# Overlay files

# The following file will be added
overlays/custom/configmap.yaml
# The following file will replace svc.yaml
overlays/custom/svc.yaml
# The following file will patch deployment.yaml
overlays/custom/deployment_patch.yaml
```

A file named `foo` will replace a file called `foo` from the base resources or a previous overlay.  In order to patch
the contents of a file the convention of adding `_patch.` (notice the trailing period) to the filename is used. The string `_patch.`
will be replaced with `.` from the file name and that will be used as the target.  For example `deployment_patch.yaml`
will target `deployment.yaml`.  The patch will be applied using JSON Merge, Strategic Merge Patch, or JSON Patch.
Which strategy is used is based on the file content. Even though JSON strategies are used, the files can be written
using YAML syntax.

## Cluster and Bundle State

See [Cluster and Bundle state](./cluster-bundles-state.md).

## Nested GitRepo CRs

Nested `GitRepo CRs` (defining a `GitRepo` that points to a repository containing one or more `GitRepo` resources) is supported.
You can use this feature to take advantage of `GitOps` in your `GitRepo` resources or, for example, to split complex scenarios into more than one `GitRepo` resource.
When finding a `GitRepo` in a `Bundle` Fleet will simply deploy it as any other resource.

See [this example](https://github.com/rancher/fleet-examples/tree/master/single-cluster/multi-gitrepo).