Yampl (yaml + tmpl) templates YAML values based on line-comments.
Yampl is available in brew or as a Docker container.
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brew install clevyr/tap/yamplClick to expand
There are two actions available for CI/CD usage:
- clevyr/setup-yampl-action: Installs yampl during a GitHub Action run.
- clevyr/yampl-action: Installs yampl, runs yampl with the given inputs, then optionally creates a commit for you.
Click to expand
yampl has a Docker image available at ghcr.io/clevyr/yampl
docker pull ghcr.io/clevyr/yamplTo use this image, you will need to volume bind the desired directory into the
Docker container. The container uses /data as its workdir, so if you wanted
to template example.yaml in the current directory, you could run:
docker run --rm -it -v "$PWD:/data" ghcr.io/clevyr/yampl example.yaml ...Click to expand
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If you don't have it already, install the
ca-certificatespackagesudo apt install ca-certificates
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Add Clevyr's apt repository
echo 'deb [trusted=yes] https://apt.clevyr.com /' | sudo tee /etc/apt/sources.list.d/clevyr.list -
Update apt repositories
sudo apt update
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Install yampl
sudo apt install yampl
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If you don't have it already, install the
ca-certificatespackagesudo yum install ca-certificates
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Add Clevyr's rpm repository to
/etc/yum.repos.d/clevyr.repo[clevyr] name=Clevyr baseurl=https://rpm.clevyr.com enabled=1 gpgcheck=0
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Install yampl
sudo yum install yampl
Click to expand
Install yampl-bin with your AUR helper of choice.
View the generated docs for flag and command reference. Also, see templating and example sections.
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Template with a single value:
$ cat example.yaml name: Clevyr #yampl {{ .name }} $ yampl example.yaml -v name='Clevyr Inc.' name: Clevyr Inc. #yampl {{ .name }}
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Template with multiple values:
$ cat example.yaml image: nginx:stable #yampl {{ .repo }}:{{ .tag }} $ yampl example.yaml -v repo=docker.io/nginx -v tag=1.27.0 image: docker.io/nginx:1.27.0 #yampl {{ .repo }}:{{ .tag }}
Note
All variables must be set for a node to be changed.
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Using a Sprig function:
$ cat example.yaml name: Clevyr #yampl {{ upper current }} $ yampl example.yaml name: CLEVYR #yampl {{ upper current }}
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Using the
repohelper function:$ cat example.yaml image: nginx:1.26.1 #yampl {{ repo current }}:{{ .tag }} $ yampl example.yaml -v tag=1.27.0 image: nginx:1.27.0 #yampl {{ repo current }}:{{ .tag }}
Click to expand
Here is a simple Kubernetes Deployment with an Nginx image:
apiVersion: apps/v1
kind: Deployment
metadata:
name: nginx
spec:
selector:
matchLabels:
app: nginx
template:
metadata:
labels:
app: nginx
spec:
containers:
- name: nginx
image: nginx:1.26.1 #yampl nginx:{{ .tag }}
ports:
- containerPort: 80Notice the yaml comment on the same line as image.
If this file was called nginx.yaml, then you could replace the image tag by running:
yampl -i nginx.yaml -v tag=1.27.0The file would be updated in-place:
apiVersion: apps/v1
kind: Deployment
metadata:
name: nginx
spec:
selector:
matchLabels:
app: nginx
template:
metadata:
labels:
app: nginx
spec:
containers:
- name: nginx
image: nginx:1.27.0 #yampl nginx:{{ .tag }}
ports:
- containerPort: 80If you wanted to repeat yourself even less, you could use the repo function to pull the existing repo through to the output.
For example, you could change the image line to:
image: nginx:1.27.0 #yampl {{ repo current }}:{{ .tag }}This would generate the same output, but you wouldn't have to type nginx twice.
This becomes more useful when using custom Docker registries where repo names can get long.
All variables passed in with the -v flag are available during templating.
For example, the variable -v tag=latest can be used as {{ .tag }}.
All Sprig functions are available in templates, along with some extras:
Returns the current YAML node's value.
Splits a Docker repo and tag into the repo component:
repo "nginx:stable-alpine"
The above produces nginx.
Splits a Docker repo and tag into the tag component:
tag "nginx:stable-alpine"
The above produces stable-alpine
By default, templated values are not explicitly quoted. This can cause problems with tools that require specific types. If you require a specific type for a field, you can add a tag to the template prefix.
Supported tags:
#yampl:bool#yampl:str#yampl:int#yampl:float#yampl:seq#yampl:map
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String
The following could be interpreted as either a string or an int:
$ cat example.yaml num: #yampl {{ .num }} $ yampl example.yaml -v num=2009 num: 2009 #yampl {{ .num }}
If this field must be a string, you could add the
strtag:$ cat example.yaml num: #yampl:str {{ .num }} $ yampl example.yaml -v num=2009 num: "2009" #yampl:str {{ .num }}
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Sequence
$ cat example.yaml seq: #yampl:seq {{ .seq }} $ yampl example.yaml -v seq='[a, b, c]' seq: #yampl {{ .seq }} - a - b - c
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Map
$ cat example.yaml map: #yampl:map {{ .map }} $ yampl example.yaml -v map='{message: hello world}' map: #yampl {{ .map }} message: hello world