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Resource Task
The resource task provides methods to persist data to a file in the scope of a
process as well as to load data from files. The resource task supports JSON,
YAML and string formats.
The task is provided automatically by Concord and does not require any external dependencies.
Reading a Resource
The asJson method of the resource task can read a JSON-file resource and
create a json object.
flows:
default:
- expr: ${resource.asJson('sample-file.json')}
out: jsonObj
# we can now use it like a simple object
- log: ${jsonObj.any_key}
The asString method can read a file resource and create a string object with
the content.
- log: ${resource.asString('sample-file.txt')}
The asYaml method supports reading files using the YAML format.
flows:
default:
- expr: ${resource.asYaml('sample-file.yml')}
out: ymlObj
# we can now use it like a simple object
- log: ${ymlObj.any_key}
Writing a Resource
The writeAsJson method of the resource task can write a JSON object into a
JSON-file resource.
flows:
default:
- set:
newObj:
name: testName
type: testType
- log: ${resource.writeAsJson(newObj)}
The writeAsString method is used to write a file with string content.
- log: ${resource.writeAsString('test string')}
The writeAsYaml method supports the YAML format.
The writeAs* methods return the path of the newly created file as
result. These values can be stored in a variable later be used to read content
back into the process with the read methods.
Parse JSON String
The fromJsonString method of the resource task can parse a JSON string to a
corresponding Java object.
flows:
default:
- set:
jsonString: '{"name":"Concord"}'
- expr: ${resource.fromJsonString(jsonString)}
out: jsonObj
- log: "Hello ${jsonObj.name}!"
Format
The printJson method of the resource task serializes a given object, or JSON
string, to a condensed JSON-formatted string. This can be useful for generating
JSON string for other tasks. This is more memory-efficient than the
prettyPrintJson method.
- set:
jsonString: ${resource.printJson('{"testKey":"testValue"}')}
Pretty Format
The prettyPrintJson method of the resource task allows you to create a
version of a JSON string or an object, that is better readable in a log or other
output.
- log: ${resource.prettyPrintJson('{"testKey":"testValue"}')}
flows:
default:
- set:
newObj:
name: testName
type: testType
- log: ${resource.prettyPrintJson(newObj)}
The prettyPrintYaml method can be used to format data as YAML with an option
to add additional indentation:
flows:
default:
- set:
data:
x: 1
y:
a: 10
b: 20
- set:
result: |
data: ${resource.prettyPrintYaml(data, 2)} # adds 2 spaces to each line
- log: |
-------------------------------------------
${result}
