...
Use Case Walkthrough
1. Deploying an Artifact
User builds their application jar the same way they build it today. They make a call to deploy their artifact (jar).A development team creates a project built on top of CDAP. Their CI build runs and produces a jar file. An administrator deploys the jar by making a REST call:
| Code Block |
|---|
POST /namespaces/default/artifacts/myapp --data-binary @myapp-1.0.0.jar |
CDAP opens the jar, figures out the artifact version based on the the bundle-version as in the artifact versionmanifest, figures out what apps, programs, datasets, and plugins are in the artifact, then stores the artifact on the filesystem and metadata in a table.
The user administrator can examine the metadata by making a call:
| Code Block |
|---|
GET /namespaces/default/artifacts/myapp/versions/1.0.0
{
"name": "purchase",
"version": "3.1.0",
"meta": {
"created": "1234567890000",
...
},
"classes": {
"apps": [
{
"className": "co.cask.cdap.examples.myapp.MyApp",
"properties": {
"stream": {
"name": "stream",
"description": "The name of the stream to read from. Defaults to 'A'.",
"type": "string",
"required": false
},
"table": {
"name": "table",
"description": "The name of the table to write to. Defaults to 'X'.",
"type": "string",
"required": false,
},
"flowConfig": {
"name": "flow",
"description": "",
"type": "config",
"fields": {
"reader": {
"name": "reader",
"description": "",
"type": "config",
"required": true,
"fields": {
"name": {
"name": "name",
"description": "The name of the reader plugin to use.",
"type": "string",
"required": true
},
"properties": {
"name": "properties",
"description": "The properties needed by the chosen reader plugin.",
"type": "plugin",
"plugintype": "reader",
"required": true
}
}
},
"writer": { ... }
}
}
}
}
],
"flowsplugins": [
... ], {
"flowlets": [ ... ], "plugins": [
{
"name": "default",
"type": "reader",
"description": "Writes timestamp and body as two columns and expects the row key to come as a header in the stream event.",
"className": "co.cask.cdap.examples.myapp.plugins.DefaultStreamReader",
"configFieldName": "config",
"properties": {
"rowkey": {
"name": "rowkey",
"description": "The header that should be used as the row key to write to. Defaults to 'rowkey'.",
"type": "string",
"required": false
}
}
}
],
"flows": [ ... ],
}
} |
...
"flowlets": [ ... ],
"datasetModules": [ ... ]
}
} |
2. Creating an Application
The administrator notices there is an app 'co.cask.cdap.examples.myapp.MyApp' contained in the artifact. Based on the app properties, the admin gathers that it needs a config of the form:
| Code Block |
|---|
{
"stream": "A",
"table": "X",
"flow": {
"reader": {
"name": "<some plugin name>",
"properties": { <properties for plugins of type "reader"> }
},
"writer": { ... }
}
} |
He then makes a call to see what plugins of type 'reader' are available:
| Code Block |
|---|
GET /namespaces/default/plugintypes/reader
[
{
"type": "reader",
"name": "default",
"description": "Writes timestamp and body as two columns and expects the row key to come as a header in the stream event.",
"className": "co.cask.cdap.examples.myapp.plugins.DefaultStreamReader"
"artifact": {
"namespace": "default",
"name": "myapp",
"version": "1.0.0"
}
}
] |
It looks like there is only one plugin of type reader available. Another call gives more details about what that plugin requires:
| Code Block |
|---|
GET /namespaces/default/plugintypes/reader/plugins/default
[
{
"type": "reader",
"name": "default",
"description": "Writes timestamp and body as two columns and expects the row key to come as a header in the stream event.",
"className": "co.cask.cdap.examples.myapp.plugins.DefaultStreamReader",
"properties": {
"rowkey": {
"name": "rowkey",
"description": "The header that should be used as the row key to write to. Defaults to 'rowkey'.",
"type": "string",
"required": false
}
},
"artifact": {
"namespace": "default",
"name": "myapp",
"version": "1.0.0"
}
}
] |
contained in the artifact.
Users will still be able to deploy an app in one call. Suppose a user wants to deploy their application contained in myapp-1.0.0.jar. They make the same RESTful call they would today:
...