Customizing Templates and Modifying Default Templates

- `seconds`: Converts a [duration](/reference/compose-file/extension.md#specifying-durations) into an integer - `uppercase`: Converts a string into upper case characters - `title`: Converts a string by capitalizing the first letter of each word - `safe`: Converts a string into a safe identifier, replacing all characters (except lowercase a-z) with `-` - `truncate`: Removes the N first elements from a list - `join`: Groups elements from a list into a single string, using a separator - `base64`: Encodes a string as base64 used in Kubernetes for encoding secrets - `map`: Transforms a value according to mappings expressed as `"value -> newValue"` strings - `indent`: Writes string content indented by N spaces - `helmValue`: Writes the string content as a template value in the final file In the following example, the template checks if a healthcheck interval is specified for a service, applies the `seconds` function to convert this interval into seconds and assigns the value to the `periodSeconds` attribute. ```yaml {{ if $service.healthcheck.interval }} periodSeconds: {{ $service.healthcheck.interval | seconds }}{{ end }} {{ end }} ``` ## Customization As Kubernetes is a versatile platform, there are many ways to map Compose concepts into Kubernetes resource definitions. Compose Bridge lets you customize the transformation to match your own infrastructure decisions and preferences, with various level of flexibility and effort. ### Modify the default templates You can extract templates used by the default transformation `docker/compose-bridge-kubernetes`, by running `compose-bridge transformations create --from docker/compose-bridge-kubernetes my-template` and adjusting the templates to match your needs. The templates are extracted into a directory named after your template name, in this case `my-template`. It includes a Dockerfile that lets you create your own image to distribute your template, as well as a directory containing the templating files. You are free to edit the existing files, delete them, or [add new ones](#add-your-own-templates) to subsequently generate Kubernetes manifests that meet your needs. You can then use the generated Dockerfile to package your changes into a new transformation image, which you can then use with Compose Bridge: ```console $ docker build --tag mycompany/transform --push . ``` You can then use your transformation as a replacement: ```console $ compose-bridge convert --transformations mycompany/transform ```

Compose Bridge offers customization options to align Compose concepts with Kubernetes resource definitions. One method involves modifying the default templates. Users can extract templates from the `docker/compose-bridge-kubernetes` transformation using `compose-bridge transformations create --from docker/compose-bridge-kubernetes my-template`. The extracted templates can be edited, deleted, or augmented. The provided Dockerfile can then be used to package the changes into a new transformation image. Finally, users can convert using the custom transformation by running: `compose-bridge convert --transformations mycompany/transform`.