adopt latest custom build task changes

- single BuildTaskHandler instead of BuildTaskProvider/BuildTaskHandler
  approach
- static build task handler config moved to meta
- default build task properties are now returned as name/value pairs
  using property config
- runWith to declare dependencies across build task handlers, ensuring
  correct dependency graph
- optional getTasks method to implement build task specific constraints

cds-plugin-openapi/index.js

@@ -1,53 +1,29 @@
 /* eslint-disable require-await */
-const path = require("path")
-const fs = require("fs")
-const cds = require('@sap/cds'), { BuildTaskProvider, BuildTaskHandler } = cds.build
+const cds = require('@sap/cds'), { BuildTaskHandler } = cds.build
 const cdsdk = require('@sap/cds-dk')
-const logger = cds.log("build")
 
-// module.exports.activate = () => {
-    cds.build.registerProvider(
-        new (class extends BuildTaskProvider {
-            get id() {
-                return 'openapi'
-            }
-            get dependents() {
-                return ['node-cf', 'java-cf']
-            }
-            applyDefaults(task) {
-                task.src = task.src || cds.env.folders.srv.replace(/\/$/, '')
-            }
-            get handler() {
-                return class extends BuildTaskHandler {
-                    async clean() {
-                        fs.rm(path.join(this.task.dest, "openapi-docs"), { recursive: true, force: true }, (err) => err ? logger.error(err) : '')
-                    }
+cds.build.register(class OpenApiHandler extends BuildTaskHandler {
+    static get meta() {
+        return {
+            id: 'openapi',
+            runWith: ['node-cf', 'java-cf'],
+            config: { src: cds.env.folders.srv.replace(/\/$/, '') }
+        }
+    }
+    async clean() {
+        return this.remove('openapi-docs')
+    }
+    async build() {
+        const model = await this.model()
+        const { options } = this.task
 
-                    async build() {
-                        const model = await this.model()
-                        const { options } = this.task
-
-                        // generate openapi files for all services
-                        await Promise.all(cds.linked(model).services.map(service => {
-                            const openApi = cdsdk.compile.to.openapi(model, {
-                                service: service.name,
-                                'openapi:diagram': String(options.diagram) === 'true'
-                            })
-                            this.write(openApi).to(`openapi-docs/${service.name}.openapi3.json`)
-                        }))
-                    }
-                }
-            }
-            /**
-             * Additional constraints can be defined, e.g. generate openapi service specification in production builds only.
-             * > cds build --production
-             * > cds build --for node-cf --production 
-             */ 
-            // async lookupTasks() {
-            //     if (process.env.NODE_ENV === 'production') {
-            //         return [{ for: this.id }]
-            //     }
-            // }
-        })()
-    )
-// }
+        // generate openapi files for all services
+        await Promise.all(cds.linked(model).services.map(service => {
+            const openApi = cdsdk.compile.to.openapi(model, {
+                service: service.name,
+                'openapi:diagram': String(options.diagram) === 'true'
+            })
+            this.write(openApi).to(`openapi-docs/${service.name}.openapi3.json`)
+        }))
+    }
+})