Application Accelerator sample accelerator.yaml file
This topic provides you with a sample accelerator file to get you started writing your own accelerators in Tanzu Application Platform (commonly known as TAP).
accelerator.yaml
Sample accelerator.yaml file:
accelerator:
# The `accelerator` section serves to document how an accelerator is presented to the
# user in the accelerator web UI.
# displayName: a descriptive human-readable name. Make this short so as to look nice
# in a list of many accelerators shown to a user.
displayName: Hello Spring Boot
# description: a more detailed description that a user can see if they took a closer
# look at a particular accelerator.
description: Simple Hello World Rest Service based on Spring Boot
# iconUrl: Optional, a nice colorful, icon for your accelerator to make it stand out visually.
iconUrl: https://raw.githubusercontent.com/vmware-tanzu/application-accelerator-samples/main/icons/icon-cloud.png
# tags: A list of classification tags. The UI allows users to search for accelerators based on tags
tags:
- Java
- Spring
- Function
# options are parameters that can affect how the accelerator behaves.
# The purpose of the options section is
# - to list all applicable options
# - describe each option in enough detail so that the UI can create
# a suitable input widget for it.
options: # a list of options
# a first option
- name:
greeting
# name: each option must have a name.
# This must be
# - camelCase
# - unique (i.e. no two options can have the same name)
# This is like a variable used by the accelerator to refer to
# and use the value during its execution.
# This name is internal to your accelerator and is not shown to
# the user.
label:
Greeting Message
# A human readable version of the `name`. This is used to identify an
# option to the user in the UI.
# This should be short (so as not to look ugly in a ui with limited
# space available for labeling the input widgets).
# There are no limits on what characters can be used in the label (so spaces
# are allowed).
description:
Greeting message displayed by the Hello World app.
# An optional more detailed description / explanation that can be shown to
# to the user in the UI when the short label alone might not be enough to understand
# its purpose.
dataType:
string
# type of data the accelerator expects during execution (this is
# like the type of the 'variable'.
# possible dataTypes are string, boolean, number or [string] (the latter meaning a
# list of strings
inputType:
text
# Related to the dataType but somewhat independent, this identifies the type
# of widget shown in the ui. Available types are:
# - text - the default
# - textarea (single text value with larger input that allows linebreaks)
# - checkbox - multivalue selection from choices
# - select - single value selection from choices
# - radio - alternative single value selection from choices
# - tag - multivalue input ui for entering single-word tags
required: true
defaultValue: Hello Accelerator
# second option:
- name: packageName
label: "Package Name"
description: Name of Java package
dataType: string
inputType: text
defaultValue: somepackage
# another option:
- name: buildType
label: Build Type
description: Choose whether to use Maven or Gradle to build the project.
dataType: string
inputType: select
choices:
- value: Maven
text: Maven (pom.xml)
- value: Gradle
text: Gradle (build.gradle)
accelerator.axl
The accelerator.axl file describes how to take the files from the accelerator repo root folder and transform them into the contents of a generated project. The transformation operates on the files as a set and can do things such as:
- Filter the set of files: Removing or keeping only files that match certain criteria.
- Change the contents of a file: For example, replacing strings within the file.
- Rename or move files: Changing the paths of the files.
Sample accelerator.axl file:
// this is the 'global' transform. It produces the final set of
// files to be zipped and returned from the accelerator.
// As input it receives all the files from the accelerator repo root.
engine {
// 'let' defines additional variables and assign them values
// These 'derived symbols' function much like options, but instead of
// being supplied from a UI widget, they are computed by the accelerator itself.
let includePoms = "#buildType == 'Maven'",
includeGradle = "#buildType == 'Gradle'" in {
// This defined `include` filters the set of files
// retaining only those matching a given list of path patterns.
// This can ensure that only files in the repo matching the list of
// patterns will be seen / considered by the accelerator.
Include({"**/*.md" , "**/*.xml" , "**/*.gradle" , "**/*.java"})
// This defined `exclude` further restricts what files are considered.
// This example ensures files in any directory called `secret` are never considered.
Exclude({"**/secret/**"})
// This merge section executes each of its children 'in parallel'.
// Each child receives a copy of the current set of input files.
// (i.e. the files that are remaining after considering the `include` and `exclude`.
// Each of the children thus produces a set of files.
// Merge then combines all the files from all the children, as if by overlaying them on top of each other
// in the same directory. If more than one child produces a file with the same path,
// this 'conflict' is resolved by dropping the file contents from the earlier child
// and keeping only the later one.
// merge child 1: this child node wants to contribute 'gradle' files to the final result
if (includeGradle) {
Include({"*.gradle"})
}
// merge child 2: this child wants to contribute 'pom' files to the final result
+ if (includePoms) {
Include({"pom.xml"})
}
// merge child 3: this child wants to contribute Java code and README.md to the final result
// Using the dot operator it ensures that the substitions are done first before merging the file set
+ Include({"**/*.java", "README.md"}).ReplaceText(substitions: {{text: "Hello World!", with: #greeting}})
// other values are `UseFirst`, `UseLast`, or `Append`
// when merging (or really any operation) produces multiple files at the same path
// this defines how that conflict is handled.
// Fail: raise an error when conflict happens
// UseFirst: keep the contents of the first file
// UseLast: keep the contents of the last file
// Append: keep both as by using `cat <first-file> > <second-file>`).
UniquePath(Fail)
RewritePath("(.*)simpleboot(.*)", #g1 + #packageName + #g2)
ReplaceText({{text: "simpleboot", with: #packageName}})
}
}
