[[yaml-dsl-other]]
= Yaml Dsl Component
:docTitle: Yaml Dsl
:artifactId: camel-yaml-dsl
:description: Camel DSL with YAML
:since: 3.9
:supportLevel: Preview
include::{cq-version}@camel-quarkus:ROOT:partial$reference/others/yaml-dsl.adoc[opts=optional]
//Manually maintained attributes
:group: DSL

*Since Camel {since}*

== Defining a route

A route is collection of elements defined as follows:

[source,yaml]
----
- from: #<1>
    uri: "direct:start"
    steps: #<2>
      - filter:
          expression:
            simple: "${in.header.continue} == true"
          steps: #<2>
            - to:
                uri: "log:filtered"
      - to:
          uri: "log:original"
----
<1> route entry point, by default `from` and `rest` are supported
<2> processing steps

[NOTE]
====
Each step is represented by a YAML map that has a single entry where the field name is the EIP name
====

As general rule each step provide all the parameters the related definition declares but there are some minor differences/enhancements:

- *Output Aware Steps*
+
Some steps such as `filter` and `split` have their own pipeline when an exchange matches the filter expression or for the items generated by the split expression, such pipeline can be defined by the `steps` field:
+
[source,yaml]
----
filter:
  expression:
    simple: "${in.header.continue} == true"
      steps:
        - to:
            uri: "log:filtered"
----
+

- *Expression Aware Steps*
+
Some EIP such as `filter` and `split` supports the definition of an expression through the `expression` field:
+
[source,yaml]
.Explicit Expression field
----
filter:
    expression:
      simple: "${in.header.continue} == true"
----
+
To make the DSL less verbose, the `expression` field can be omitted:
+
[source,yaml]
.Implicit Expression field
----
filter:
    simple: "${in.header.continue} == true"
----
+
In general expression can be defined inline like in the examples above but in case you need provide more information, you can 'unroll' the expression definition and configure any single parameter the expression defines.
+
[source,yaml]
.Full Expression definition
----
filter:
    tokenize:
      token: "<"
      end-token: ">"
----

- *Data Format Aware Steps*
+
Some EIP such as `set-body` and `marshal` supports the definition of data formats through the `data-format` field:
+
[source,yaml]
.Explicit Data Format field
----
set-body:
    data-format:
      json:
        library: Gson
----
+
To make the DSL less verbose, the `data-format` field can be omitted:
+
[source,yaml]
.Implicit Data Format field
----
set-body:
    json:
      library: Gson
----
+
[NOTE]
====
In case you want to use the data-format's default settings, you need to place an empty block as data format parameters, like `json: {}`
====

== Defining endpoints

To define an endpoint with the YAML dsl you have three options:

. Using a classic Camel URI:
+
[source,yaml]
----
- from:
    uri: "timer:tick?period=1s"
    steps:
      - to:
          uri: "telegram:bots?authorizationToken=XXX"
----
. Using URI and parameters:
+
[source,yaml]
----
- from:
    uri: "timer://tick"
    parameters:
      period: "1s"
    steps:
      - to:
          uri: "telegram:bots"
          parameters:
            authorizationToken: "XXX"
----
. Using the YAML implementation of the xref:manual::Endpoint-dsl.adoc[Endpoint DSL]:
+
[source,yaml]
----
- from:
    timer:
      name: "tick"
      period: "1s"
    steps:
      - telegram:
          type: "bots"
          authorizationToken: "XXX"
----

[WARNING]
====
Support for the Endpoint DSL with YAML is experimental and subject to changes.
====
[NOTE]
====
Support for Endpoint DSL auto completion https://github.com/apache/camel-k-runtime/issues/485[is not yet available].
====

== Defining beans

In addition to the general support for creating beans provided by xref:others:main.adoc#_specifying_custom_beans[Camel Main], the YAML DSL provide a convenient syntax to define and configure them:

[source,yaml]
----
- beans:
  - name: beanFromMap  # <1>
    type: com.acme.MyBean # <2>
    properties: # <3>
      foo: bar
----
<1> the name of the bean which will be used to bound the instance to the Camel Registry
<2> the full qualified class name of the bean
<3> the properties of the bean to be set

The properties of the bean can be defined using either a map or properties style as shown in the example below:

[source,yaml]
----
- beans:
  # map style
  - name: beanFromMap
    type: com.acme.MyBean
    properties:
      field1: 'f1'
      field2: 'f2'
      nested:
        field1: 'nf1'
        field2: 'nf2'
  # properties style
  - name: beanFromProps
    type: com.acme.MyBean
    properties:
      field1: 'f1_p'
      field2: 'f2_p'
      nested.field1: 'nf1_p'
      nested.field2: 'nf2_p'
----

[NOTE]
====
The `beans` elements can only be used as root element
====

== Examples

You can find a set of examples using `camel-yaml-dsl` in https://github.com/apache/camel-examples[Camel Examples]
which demonstrate creating Camel Routes with YAML.
