@razee/mustachetemplate
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Razee: component to use the Mustache template processor on kubernetes resource configurations.
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# MustacheTemplate
[](https://travis-ci.com/razee-io/MustacheTemplate)
MustacheTemplate is the next step of complexity when working with Razee. With
MustacheTemplate we can inject cluster specific environment variables into
resources before applying them to a cluster. We even use this injection method
as the mechanism for version control of our resources.
The basic operation of MustacheTemplate is to collect all values defined in
`.spec.envFrom` and `.spec.env`, then use those values to process all yaml
defined in the `.spec.templates`, and finally apply the processed yaml to the cluster.
## Install
[Razee Deploy Delta](https://github.com/razee-io/razeedeploy-delta) is the
recommended way to install MustacheTemplate.
Optional: [Advanced Controller Options](#cluster-wide-controls)
**Warning:** By default, Razeedeploy runs as cluster wide admin. Any user that has
permission to create a razeedeploy resource (RemoteResource or MustacheTemplate)
has the ability to escalate their privileges. To prevent privilege escalation,
cluster owners should restrict which users are allowed to create razeedeploy
resources. Alternatively, you can setup [ImpersonationWebhook](https://github.com/razee-io/ImpersonationWebhook)
and then [enable user impersonation](#enable-cluster-wide-user-impersonation) to
ensure razeedeploy only allows users to do operations that they have already been
granted access to do.
## Resource Definition
### Sample
```yaml
apiVersion: deploy.razee.io/v1alpha2
kind: MustacheTemplate
metadata:
name: <mustache_template_name>
namespace: <namespace>
spec:
clusterAuth:
impersonateUser: razeedeploy
envFrom:
- genericMapRef:
apiVersion: deploy.razee.io/v1alpha2
kind: FeatureFlagSetLD
name: myLDProject
namespace: default
env:
- name: app-label
value: "deployment 1"
- name: desired-replicas
optional: true
default: 3
valueFrom:
configMapKeyRef:
name: nginx-config
key: replicas
type: number
- name: json-config
valueFrom:
configMapKeyRef:
name: nginx-config-globals
key: my-app-config
type: json
- name: json-config
overrideStrategy: merge
valueFrom:
configMapKeyRef:
name: nginx-config-dev
key: my-app-config-dev-overrides
type: json
- name: json-merge-selectors
overrideStrategy: merge
valueFrom:
configMapKeyRef:
matchLabels:
app: json-rules-merge
key: json-config
type: json
templates:
- apiVersion: v1
kind: ConfigMap
metadata:
name: test-config
data:
sample: "{{ desired-replicas }}"
strTemplates:
- |
apiVersion: apps/v1
kind: Deployment
metadata:
name: nginx-deployment
labels:
app: nginx
deployment: {{ app-label }}
spec:
replicas: {{ desired-replicas }}
selector:
matchLabels:
app: nginx
template:
metadata:
labels:
app: nginx
spec:
containers:
- name: nginx
image: nginx:1.7.9
ports:
- containerPort: 80
```
### Spec
**Path:** `.spec`
**Description:** `spec` is required and **must** include at least one [`envFrom`
, `env`] and at least one [`templates`, `strTemplates`].
**Schema:**
```yaml
spec:
type: object
allOf:
- anyOf:
- required: [templates]
- required: [strTemplates]
- anyOf:
- required: [envFrom]
- required: [env]
properties:
clusterAuth:
type: object
...
templateEngine:
type: string
...
custom-tags:
type: array
...
envFrom:
type: array
...
env:
type: array
...
templates:
type: array
...
strTemplates:
type: array
...
```
### User Impersonation
**Path:** `.spec.clusterAuth.impersonateUser`
**Description:** [Impersonates](https://kubernetes.io/docs/reference/access-authn-authz/authentication/#user-impersonation)
a user for the given resource. This includes all actions the controller must
make related to the resource (fetching envs, getting resources, applying
resources, etc.). ImpersonateUser only applies to the single RazeeDeploy
resource that it has been added to.
**Enable Feature:** [Enable User Impersonation](#enable-cluster-wide-user-impersonation)
**Warning:** By default, Razeedeploy runs as cluster wide admin. Any user that has
permission to create a razeedeploy resource (RemoteResource or MustacheTemplate)
has the ability to escalate their privileges. To prevent privilege escalation,
cluster owners should restrict which users are allowed to create razeedeploy
resources. Alternatively, you can setup [ImpersonationWebhook](https://github.com/razee-io/ImpersonationWebhook)
and then [enable user impersonation](#enable-cluster-wide-user-impersonation) to
ensure razeedeploy only allows users to do operations that they have already been
granted access to do.
**Schema:**
```yaml
properties:
clusterAuth:
type: object
properties:
impersonateUser:
type: string
```
**Default:** `'razeedeploy'`
### Templating Engine
**Path:** `.spec.templateEngine`
**Description:** Specifying which templating engine to use, the available
options are `mustache` and `handlebars`
**Schema:**
```yaml
properties:
templateEngine:
type: string
pattern: "^mustache$|^handlebars$"
```
**Default:** `'mustache'`
### Custom Tags
**Path:** `.spec.custom-tags`
**Description:** Specifying custom tags will override the default mustache tags.
This can be useful when you need to reserve `{{ }}` for some other processing.
**Schema:**
```yaml
custom-tags:
type: array
maxItems: 2
minItems: 2
items:
type: string
maxLength: 3
minLength: 2
```
**Default:** `['{{', '}}']`
### EnvFrom
**Path:** `.spec.envFrom`
**Description:** Allows you to pull in all values from a resource's `.data` section
to be used in template processing. ie. ConfigMaps would use the `configMapRef` key
and CRDs with a high level `.data` section can be pulled in by using the
`genericMapRef` key. The keys pulled from the resource are what you would use
to match values into your templates.
**Note:** values are loaded in from `.spec.envFrom` before `.spec.env`, and
top down. Any values with the same key/name will be overwritten, last in wins.
**Schema:**
```yaml
envFrom:
type: array
items:
type: object
oneOf:
- required: [configMapRef]
- required: [secretMapRef]
- required: [genericMapRef]
properties:
optional:
type: boolean
configMapRef:
type: object
required: [name]
properties:
name:
type: string
namespace:
type: string
secretMapRef:
type: object
required: [name]
properties:
name:
type: string
namespace:
type: string
genericMapRef:
type: object
required: [apiVersion, kind, name]
properties:
apiVersion:
type: string
kind:
type: string
name:
type: string
namespace:
type: string
```
#### EnvFrom Optional
**Path:** `.spec.envFrom[].optional`
**Description:** If fetching env/envFrom resource fails, MustacheTemplate will stop
execution and report error to `.status`. You can allow execution to continue by
marking a reference as optional.
**Schema:**
```yaml
optional:
type: boolean
```
**Default:** `false`
### Env
**Path:** `.spec.env`
**Description:** Allows you to pull in a single value from a resource's `.data`
section to be used in template processing. ie. ConfigMaps would use the
`configMapKeyRef` key and CRDs with a high level `.data` section can be pulled
from by using the `genericKeyRef` key. `.spec.env.name` is what you would use to
match values into your templates. You can also specify a `type` that we will
convert your fetched string into, before injecting into your template (one of
[number, boolean, json, jsonString, base64]). Note: when no type is specified,
the value will be treated as a normal string.
**Note:** values are loaded in from `.spec.envFrom` before `.spec.env`, and
top down. Any values with the same key/name will be overwritten, last in wins.
If you want to have json values merged, specify [`overrideStrategy: merge`](#env-overridestrategy)
**Schema:**
```yaml
env:
type: array
items:
type: object
allOf:
- required: [name]
- # all array items should be oneOf ['value', 'valueFrom']
oneOf:
- required: [value]
# if 'value', neither 'optional' nor 'default' may be used
not:
anyOf:
- required: [default]
- required: [optional]
- required: [valueFrom]
# if 'valueFrom', you must define oneOf:
oneOf:
- # neither 'optional' nor 'default' is used
not:
anyOf:
- required: [default]
- required: [optional]
- # 'optional' is used by itself
required: [optional]
not:
required: [default]
- # 'optional' and 'default' are used together IFF optional == true
required: [optional, default]
properties:
optional:
enum: [true]
properties:
optional:
type: boolean
default:
x-kubernetes-int-or-string: true
name:
type: string
overrideStrategy:
type: string
pattern: "^merge$|^replace$"
value:
x-kubernetes-int-or-string: true
valueFrom:
type: object
oneOf:
- required: [configMapKeyRef]
- required: [secretKeyRef]
- required: [genericKeyRef]
properties:
configMapKeyRef:
type: object
oneOf:
- required: [key, name]
- required: [key, matchLabels]
properties:
name:
type: string
key:
type: string
namespace:
type: string
type:
type: string
enum: [number, boolean, json, jsonString, base64]
matchLabels:
type: object
additionalProperties: true
secretKeyRef:
type: object
oneOf:
- required: [key, name]
- required: [key, matchLabels]
properties:
name:
type: string
key:
type: string
namespace:
type: string
type:
type: string
enum: [number, boolean, json, jsonString, base64]
matchLabels:
type: object
additionalProperties: true
genericKeyRef:
type: object
oneOf:
- required: [apiVersion, kind, name, key]
- required: [apiVersion, kind, matchLabels, key]
properties:
apiVersion:
type: string
kind:
type: string
name:
type: string
key:
type: string
namespace:
type: string
type:
type: string
enum: [number, boolean, json, jsonString, base64]
matchLabels:
type: object
additionalProperties: true
```
#### Env Optional
**Path:** `.spec.env[].optional`
**Description:** If fetching env/envFrom resource fails, MustacheTemplate will stop
execution and report error to `.status`. You can allow execution to continue by
marking a reference as `optional: true`.
**Schema:**
```yaml
optional:
type: boolean
```
**Default:** `false`
#### Env Default
**Path:** `.spec.env[].default`
**Description:** If fetching env/envFrom resource fails, but `.spec.env[].optional`
is `true` and `.spec.env[].default` is defined, the default value will be used.
**Schema:**
```yaml
default:
x-kubernetes-int-or-string: true
```
#### Env OverrideStrategy
**Path:** `.spec.env[].overrideStrategy`
**Description:** If you are loading envs as json, and you want to allow overrided
values to merge instead of just replacing, specify `overrideStrategy: merge`.
**Note:** If either env defined is not a json object when merge is specified, the
behavior will revert to replace instead of merge (ie. a json object is loaded first,
then a jsonString is loaded second with `overrideStrategy: merge` specified. the
jsonString will replace the first json object instead of trying to merge with it.)
**Schema:**
```yaml
overrideStrategy:
type: string
pattern: "^merge$|^replace$"
```
**Default:** `replace`
### Managed Resource Labels
#### Reconcile
`.spec.templates.metadata.labels[deploy.razee.io/Reconcile]`
- DEFAULT: `true`
- A razeedeploy resource (parent) will clean up a resources it applies (child)
when either the child is no longer in the parent resource definition or the
parent is deleted.
- `false`
- This behavior can be overridden when a child's resource definition has
the label `deploy.razee.io/Reconcile=false`.
#### Resource Update Mode
`.spec.templates.metadata.labels[deploy.razee.io/mode]`
Razeedeploy resources default to merge patching children. This behavior can be
overridden when a child's resource definition has the label
`deploy.razee.io/mode=<mode>`
Mode options:
- DEFAULT: `Apply` (`MergePatch`)
- A simple merge, that will merge objects and replace arrays. Items previously
defined, then removed from the definition, will be removed from the live resource.
- "As defined in [RFC7386](https://tools.ietf.org/html/rfc7386), a Merge Patch
is essentially a partial representation of the resource. The submitted JSON is
"merged" with the current resource to create a new one, then the new one is
saved. For more details on how to use Merge Patch, see the RFC." [Reference](https://github.com/kubernetes/community/blob/master/contributors/devel/sig-architecture/api-conventions.md#patch-operations)
- `StrategicMergePatch`
- A more complicated merge, the kubernetes apiServer has defined keys to be
able to intelligently merge arrays it knows about.
- "Strategic Merge Patch is a custom implementation of Merge Patch. For a
detailed explanation of how it works and why it needed to be introduced, see
[StrategicMergePatch](https://github.com/kubernetes/community/blob/master/contributors/devel/sig-api-machinery/strategic-merge-patch.md)."
[Reference](https://github.com/kubernetes/community/blob/master/contributors/devel/sig-architecture/api-conventions.md#patch-operations)
- [Kubectl Apply Semantics](https://kubectl.docs.kubernetes.io/pages/app_management/field_merge_semantics.html)
- `AdditiveMergePatch`
- Similar to the default `Apply` (`MergePatch`), this is a simple merge, that
will merge objects and replace arrays. The difference is that it will
not remove fields from the live resource when they are removed from the
definition. eg. This will only add/update fields, it wont remove fields.
- If you are using this mode and find that you need to remove a field, you can
do so manually, by setting the field in the yaml defintion to have a value
of `null`. When the null value is merged with the live resource, it will
effectively delete the field.
- This mode is useful if you have very large resources and require that the
`last-applied-configuration` annotation is not injected into the resource.
- `EnsureExists`
- Will ensure the resource is created and is replaced if deleted. Will not
enforce a definition.
### Debug Individual Resource
`.spec.resources.metadata.labels[deploy.razee.io/debug]`
Treats the live resource as EnsureExist. If any Kapitan component is enforcing
the resource, and the label `deploy.razee.io/debug: true` exists on the live
resource, it will treat the resource as ensure exist and not override any changes.
This is useful for when you need to debug a live resource and don't want Kapitan
overriding your changes. Note: this will only work when you add it to live resources.
If you want to have the EnsureExist behavior, see [Resource Update Mode](#resource-update-mode).
- ie: `kubectl label mtp <your-mtp> deploy.razee.io/debug=true`
## Cluster Wide Controls
The optional `razeedeploy-config` ConfigMap can be used to customize the
controller for cluster wide actions.
Because the ConfigMap is optional, if it is created the first time, you must
restart controller pods, so the deployment can mount the ConfigMap
as a volume.
Example:
```yaml
apiVersion: v1
kind: ConfigMap
metadata:
name: razeedeploy-config
namespace: razeedeploy
data:
lock-cluster: "false"
enable-impersonation: "false"
```
### Lock Cluster
**Key:** `lock-cluster`
**Options:**
- DEFAULT: `false`
- Allows the controller to continue normal operations on the cluster.
- `true`
- Prevents the controller from updating resources on the cluster.
### Enable Cluster Wide User Impersonation
**Key:** `enable-impersonation`
**Options:**
- DEFAULT: `false`
- Prevents the controller from performing [user impersonation](#user-impersonation)
in all namespaces. Continues to allow user impersonation in the `razeedeploy`
namespace. To prevent privildge escalation, users should be restricted from
creating razeedeploy resources.
- `true`
- Allows the controller to perform [user impersonation](#user-impersonation)
in all namespaces. **See important note below about steps that should be taken
to properly configure this feature before enabling.**
**IMPORTANT:** it is highly advised to set up [ImpersonationWebhook](https://github.com/razee-io/ImpersonationWebhook)
before enabling cluster-wide impersonation. If ImpersonationWebhook is not installed
before enabling impersonation, any user on the cluster that is allowed to create
razeedeploy resources will be able to impersonate any other user. Once the ImpersonationWebhook
controller is installed and all necessary config and authorizations in place, impersonation
can be safely enabled in the `razeedeploy-config` configmap.
## Local Testing with `bin/renderlocal`
`bin/renderlocal` can be used to see what the resources generated by a
MustacheTemplate would look like.
`bin/renderlocal` arguments:
- `--mtp` a path to the template you want to render.
- `--env` a path to a file containing `ConfigMaps`, `Secrets`, or other
resources used to render the template. Any number of `--env` files can be
added; at least one is required.
- `--out` if provided, the path to write the resulting rendered resources
[OPTIONAL]
### Example
```shell
bin/renderlocal --mtp test/example/hello-mtp.yaml --env test/example/hello-cm.yaml
{..."failed to get env: {\"name\":\"greeting\",... # expected warning
kind: ConfigMap
apiVersion: v1
metadata:
name: result
namespace: default
data:
result: hello, Razee!
```
```shell
bin/renderlocal --mtp test/example/hello-mtp.yaml \
--env test/example/hello-cm.yaml --env test/example/alternate-greeting-cm.yaml
kind: ConfigMap
apiVersion: v1
metadata:
name: result
namespace: default
data:
result: howdy, Razee!
```
```shell
bin/renderlocal --mtp test/example/hello-mtp.yaml \
--env test/example/hello-cm.yaml --env test/example/alternate-greeting-cm.yaml \
--out /tmp/output.yaml \
&& cat /tmp/output.yaml
kind: ConfigMap
apiVersion: v1
metadata:
name: result
namespace: default
data:
result: howdy, Razee!
```