Add TableSyncProcess; remove previously built htmls & pdfs

docs/implementations/TableSync.adoc

@@ -0,0 +1,406 @@
+== TableSyncProcess
+include::../variables.adoc[]
+
+The `TableSyncProcess` is designed to help solve the common use-case where you have a set of records in one table,
+you want to apply a transformation to them, and then you want them to result in records in a different table.
+
+=== Sample Scenario
+For example, you may be receiving an import file feed from a partner - say, a CSV file of order records
+- that you need to synchronize into your local database's orders table.
+
+=== High Level Steps
+At a high-level, the steps of this task are:
+
+1. Get the records from the partner's feed.
+2. Decide Insert/Update - e.g., if you already have any of these orders in your database table, in which case, they need updated, versus ones
+you don't have, which need inserted.
+3. Map fields from the partner's order record to your own fields.
+4. Store the necessary records in your database (insert or update).
+
+=== What you need to tell QQQ
+`TableSyncProcess`, as defined by QQQ, knows how to do everything for a job like this, other than the part that's unique to your business.
+Those unique parts that you need to tell QQQ are:
+
+* What are the source & destination tables?
+* What are the criteria to identify source records to be processed?
+* What are the key fields are that "link" together records from the source & destination tables?
+** For the example above, imagine you have a "partnerOrderNo" field in your database's order table - then you'd need
+to tell QQQ what field in the partner's table provides the value for that field in your table.
+* How do fields / values from the source table map to fields & values in the destination table?
+
+=== Detailed Steps
+To get more specific, in a QQQ `TableSyncProcess`, here's what happens for each of the high-level steps given above:
+
+* Getting records from the partner's feed (done by QQQ):
+** Records from the source will be fetched via an Extract step, which runs a query to find the records that need processing.
+** Depending on your use-case, you may use an `ExtractViaQueryStep` (maybe with a Table Automation) or `ExtractViaBasepullQueryStep`
+(e.g., if you are polling a remote data source).
+* Deciding Insert/Update (done by QQQ):
+** Given  a set of records from the source table (e.g., output of the Extract step mentioned above), get values from the "key" field in that table.
+** Do a lookup in the destination table, where its corresponding "key" field has the values extracted from the source records.
+** For each source record, if its "key" was found in the destination table, then plan an update to that existing corresponding
+destination record; else, plan to insert a new record in the destination table.
+* Mapping values (done by your custom Application code):
+** Specifically, mapping is done in a subclass of `AbstractTableSyncTransformStep`, in the `populateRecordToStore` method.
+Of particular interest are these two parameters to that method:
+*** `QRecord destinationRecord` - as determined by the insert/update logic above, this will either be a
+new empty record (e.g., for inserting), or a fully populated record from the destination table (for updating).
+*** `QRecord sourceRecord` - this is the record being processed, from the source table.
+** This method is responsible for setting values in the `destinationRecord`, and returning that record
+(unless it has decided that for some reason the record should _not_ be stored, in which case it may return `null`).
+* Storing the records (done by QQQ):
+** This is typically done with the `LoadViaInsertOrUpdateStep`, though it is customizable if additional work is needed (e.g., via a
+subclass of `LoadViaInsertOrUpdateStep`, or a more custom subclass of `AbstractLoadStep`).
+
+=== Bare-bones Example
+For this example, let's assume we're setting up a partner-order-feed as described above, with the following details:
+
+* We have records from a partner in a table named `"partnerOrderImport"` (let's assume the records may have been created
+using the QQQ `FilesystemImporter` process).
+These records have the following fields:
+** `orderNo, date, city, state, postal, whseNo`
+* We need to synchronize those records with table in our database named `"order"`, with the following fields corresponding to those from the partner:
+** `partnerOrderNo, orderDate, shipToCity, shipToState, shipToZipCode, warehouseId`
+* The same conceptual order may appear in the `"partnerOrderImport"` multiple times, e.g., if they update some data on the order and re-transmit it to us.
+Meaning, we need to update our `"order"` records when we receive a new version an existing order.
+
+To use `*TableSyncProcess*` for solving this use-case, we'll need to create 2 things:
+
+1. A `QProcessMetaData` object, which we can create using the builder object provided by class `TableSyncProcess`.
+Note that this type of process is specialization of the standard QQQ `StreamedETLWithFrontendProcess`, as described elsewhere in this documentation.
+2. A subclass of `AbstractTableSyncTransformStep`, where we implement our mapping logic.
+Again, note that `AbstractTableSyncTransformStep` is a subclass of `AbstractTransformStep`, as used by `StreamedETLWithFrontendProcess`.
+
+And to be good programmers, we'll actually create a 3rd thing:
+
+[start=3]
+. A unit test for our Transform step.
+
+Here are examples of these pieces of code:
+
+[source,java]
+.Example of building process using the TableSyncProcess builder:
+----
+// the false argument below tells the build we are not a basepull-style process
+QProcessMetaData processMetaData = TableSyncProcess.processMetaDataBuilder(false)
+
+    // give our process a unique name within our QInstance
+    .withName("partnerOrderToLocalOrderProcess")
+
+    // tell the process to what class to use for transforming records from source to destination
+    .withSyncTransformStepClass(PartnerOrderToOrderTransformStep.class)
+
+    .getProcessMetaData();
+----
+
+[source,java]
+.Example implementation of an AbstractTableSyncTransformStep
+----
+public class PartnerOrderToOrderTransformStep extends AbstractTableSyncTransformStep
+{
+   @Override
+   protected SyncProcessConfig getSyncProcessConfig()
+   {
+      return (new SyncProcessConfig(
+         "partnerOrderImport", // source tableName
+         "orderNo",            // source table key fieldName
+         "order",              // destination tableName
+         "partnerOrderNo"      // destination table foreign key fieldName
+      ));
+   }
+
+   @Override
+   public QRecord populateRecordToStore(RunBackendStepInput runBackendStepInput, QRecord destinationRecord, QRecord sourceRecord) throws QException
+   {
+      // map simple values from source table to destination table
+      destinationRecord.setValue("orderDate", sourceRecord.get("date"));
+      destinationRecord.setValue("shipToAddressCity", sourceRecord.get("city"));
+      destinationRecord.setValue("shipToAddressState", sourceRecord.get("state"));
+      destinationRecord.setValue("shipToAddressZipCode", sourceRecord.get("postal"));
+      return (destinationRecord);
+   }
+
+}
+----
+
+[source,java]
+.Example Unit Test for a transform step
+----
+   @Test
+   void testTransformStep()
+   {
+      // insert 1 test order, that will be updated by the transform step
+      Integer existingId = new InsertAction().execute(new InsertInput("order").withRecords(List.of(
+         new QRecord().withValue("partnerOrderNo", 101).withValue("shipToState", "IL")
+      ))).getRecords().get(0).getValueInteger("id");
+
+      // set up input for the step - a list of 2 of the partner's orders
+      RunBackendStepInput input = new RunBackendStepInput();
+      input.setRecords(List.of(
+         new QRecord().withValue("orderNo", 101).withValue("state", "NY"), // will update the order above
+         new QRecord().withValue("orderNo", 102).withValue("state", "CA")  // will insert a new order
+      ));
+      RunBackendStepOutput output = new RunBackendStepOutput();
+
+      // run the code under test - our transform step
+      new PartnerOrderToOrderTransformStep().run(input, output);
+
+      // Note that by just running the transform step, no records have been stored.
+      // We can assert against the output of this step.
+
+      assertEquals(existingId, output.getRecords().get(0).getValue("id"));
+      assertEquals(101, output.getRecords().get(0).getValue("partnerOrderNo"));
+      assertEquals("NY", output.getRecords().get(0).getValue("shipToState"));
+
+      assertNull(output.getRecords().get(1).getValue("id"));
+      assertEquals(102, output.getRecords().get(1).getValue("partnerOrderNo"));
+      assertEquals("CA", output.getRecords().get(1).getValue("shipToState"));
+   }
+
+   @Test
+   void testFullProcess()
+   {
+      // todo! :)
+   }
+----
+
+=== Pseudocode process flow
+Now that we've seen the bare-bones example, let's see an even more detailed breakdown of how a full `TableSyncProcess` works,
+by looking at its 3 "ETL" steps in pseudocode:
+
+==== ExtractStep (Producer Thread)
+
+* Queries source table for records
+** Often based on Table Automations (e.g., for all newly inserted records) or Basepull pattern (polling for new/updated records).
+
+==== TransformStep (Consumer Thread)
+
+* Receives pages of records from `ExtractStep` in the `run` method.
+* Makes `sourceKeyList` by getting `sourceTableKeyField` values from the records.
+* Calls `initializeRecordLookupHelper(runBackendStepInput, sourceRecordList)`
+** Calls `getLookupsToPreLoad` to control which lookups are performed.
+* Calls `getExistingRecordsByForeignKey(runBackendStepInput, destinationTableForeignKeyField, destinationTableName, sourceKeyList);`
+** Calls `getExistingRecordQueryFilter(runBackendStepInput, sourceKeyList)` as part of querying the `destinationTable`
+** Returns the output of `buildExistingRecordsMap(destinationTableForeignKeyField, queryOutput.getRecords())`
+* foreach input record (from `sourceTable`):
+** Calls `getExistingRecord(existingRecordsByForeignKey, destinationForeignKeyField, sourceKeyValue)`
+** if an existing record was returned (and if the syncConfig says `performUpdates`), this record is set as `recordToStore`
+** else if no existing record was returned (and if the syncConfig says `performInserts`), a new record is set as `recordToStore`
+** else continue the foreach.
+** call `populateRecordToStore(runBackendStepInput, recordToStore, sourceRecord)`
+** if a record is returned it is added to the process step output (to be stored in the LoadStep)
+
+==== LoadStep (Consumer Thread)
+
+* Receives records from the output of the `TransformStep`.
+* Inserts and/or Updates `destinationTable`, with records returned by `populateRecordToStore`
+
+=== Additional Process Configuration Examples
+The following examples show how to use additional settings in the `TableSyncProcess` builder.
+
+==== UI
+While a `TableSyncProcess` will often run via a schedule and/or automation, we may also want to allow users
+to manually run it in a UI.
+
+[source,java]
+.Making our process available for a UI
+----
+QProcessMetaData processMetaData = TableSyncProcess.processMetaDataBuilder(true)
+    .withName("partnerOrderToLocalOrderProcess")
+    .withSyncTransformStepClass(PartnerOrderToOrderTransformStep.class)
+
+    // attach our process to its source table, to show up in UI
+    .withTableName("partnerOrderImport")
+
+    // add some fields to display on the review screen, in UI
+    .withReviewStepRecordFields(List.of(
+       new QFieldMetaData("clientId", QFieldType.STRING).withLabel("Client"),
+       new QFieldMetaData("warehouseId", QFieldType.STRING).withLabel("Warehouse"),
+       new QFieldMetaData("partnerOrderNo", QFieldType.STRING)))
+    .getProcessMetaData();
+----
+
+==== Basepull
+The previous example would work as a Table Automation (e.g., where the list of records identified in the
+Extract step were determined by the Automation system).
+However, a second common pattern is to use `Basepull` (e.g., if polling for updated records from a partner API endpoint).
+
+[source,java]
+.Configuring our process as a Basepull
+----
+// the true argument below tells the build we ARE a basepull-style process
+// this changes the default extract-step.
+QProcessMetaData processMetaData = TableSyncProcess.processMetaDataBuilder(false)
+    .withName("partnerOrderToLocalOrderProcess")
+    .withSyncTransformStepClass(PartnerOrderToOrderTransformStep.class)
+
+    // See Basepull documentation for details
+    .withBasepullConfiguration(new BasepullConfiguration())
+
+    // schedule our process to run automatically every minute
+    .withSchedule(new QScheduleMetaData().withRepeatSeconds(60))
+
+    .getProcessMetaData();
+----
+
+=== Additional Options in the Transform Step
+
+==== Specifying to not perform Inserts or not perform Updates
+We may have a scenario where we want our sync process to never update records if the key is already found in the destination table.
+We can configure this with an additional optional parameter to the `SyncProcessConfig` constructor:
+
+[source,java]
+.Specifying to not do updates in a TableSyncProcess
+----
+   @Override
+   protected SyncProcessConfig getSyncProcessConfig()
+   {
+      return (new SyncProcessConfig("partnerOrderImport", "orderNo", "order", "partnerOrderNo",
+         true,  // performInserts
+         false  // performUpdates
+      ));
+   }
+----
+
+Similarly, we may want to disallow inserts from a particular sync process.
+The `performInserts` argument to the `SyncProcessConfig` constructor lets us do that:
+
+[source,java]
+.Specifying to not do inserts in a TableSyncProcess
+----
+   @Override
+   protected SyncProcessConfig getSyncProcessConfig()
+   {
+      return (new SyncProcessConfig("partnerOrderImport", "orderNo", "order", "partnerOrderNo",
+         false, // performInserts
+         true   // performUpdates
+      ));
+   }
+----
+
+==== Customizing the query for existing records
+
+In some cases, a specific Table Sync process may need to refine the query filter that is used
+to lookup existing records in the destination table (e.g. for determining insert vs. update).
+
+For example, in our orders-from-a-partner scenario, if we have more than 1 partner sending us orders,
+where there could be overlapping orderNo values among them - we may have an additional field in our
+orders table to identify which partner an order came from.
+So then when we're looking up orders by `partnerOrderNo`, we would need to also include the `partnerId` field
+in our query, so that we only update orders from the specific partner that we're dealing with.
+
+To do this (to customize the existing record query filter), we need can just override the method `getExistingRecordQueryFilter`.
+Generally we would start by calling the `super` version of the method, and then add to it additional criteria.
+
+[source,java]
+.Customizing the query filter used to look for existing records
+----
+   /*******************************************************************************
+    ** Define the query filter to find existing records.  e.g., for determining
+    ** insert vs. update.  Subclasses may override this to customize the behavior,
+    ** e.g., in case an additional field is needed in the query.
+    *******************************************************************************/
+   protected QQueryFilter getExistingRecordQueryFilter(RunBackendStepInput runBackendStepInput, List<Serializable> sourceKeyList)
+   {
+      QQueryFilter filter = super.getExistingRecordQueryFilter(runBackendStepInput, sourceKeyList);
+      filter.addCriteria(new QFilterCriteria("partnerId", EQUALS, PARTNER_ID));
+      return (filter);
+   }
+----
+
+==== More efficient additional record lookups
+
+It is a common use-case to need to map various ids from a partner's system to ids in your own system.
+For the orders example, we might need to know what warehouse the order is shipping from.
+The customer may send their identifier for the warehouse, and we may need to map those identifiers to our own warehouse ids.
+
+The QQQ-provided class `RecordLookupHelper` exists to help with performing lookups like this,
+and in particular, it can be used to execute one query to fetch a full table, storing records
+by a key field, then returning those records without performing additional queries.
+
+`AbstractTableSyncTransformStep` has a protected `recordLookupHelper` member.
+If we override the method `getLookupsToPreLoad()`, then this object is
+populated by calling its `preloadRecords` method with each specified pair of tableNames and fieldNames.
+
+[source,java]
+.Specifying tables to pre-load using a RecordLookupHelper
+----
+   /*******************************************************************************
+    ** Specify a list of tableName/keyColumnName pairs to run through
+    ** the preloadRecords method of the recordLookupHelper.
+    *******************************************************************************/
+   @Override
+   protected List<Pair<String, String>> getLookupsToPreLoad()
+   {
+      return (List.of(
+         Pair.of("warehouse", "partnerWarehouseNo")
+      ));
+   }
+----
+
+If we have preloaded some lookups, we can then use them in our `populateRecordToStore` method as follows:
+[source,java]
+.Using the recordLookupHelper in populateRecordToStore
+----
+   // lookup warehouse with partnerWarehouseNo=whseNo from partner, and use our id in destination record
+   String partnerWarehouseNo = sourceRecord.getValue("whseNo");
+   Integer warehouseId = recordLookupHelper.getRecordId("warehouse", "partnerWarehouseNo", whseNo, Integer.class);
+   destinationRecord.setValue("warehouseId", warehouseId);
+----
+
+==== Additional override points
+
+There are more methods which can be overridden in your `AbstractTableSyncTransformStep` subclass,
+to provide further customizations of behaviors, specifically in the area of dealing with existing
+records (e.g., the insert/update use-case).
+[source,java]
+.Additional AbstractTableSyncTransformStep overrides
+----
+
+   /*******************************************************************************
+    ** Run the existingRecordQueryFilter - to look in the destinationTable for
+    ** any records that may need an update (rather than an insert).
+    **
+    ** Generally returns a Map, keyed by a Pair of the destinationTableForeignKeyField
+    ** and the value in that field.  But, for more complex use-cases, one can override
+    ** the buildExistingRecordsMap method, to make different keys (e.g., if there are
+    ** two possible destinationTableForeignKeyFields).
+    *******************************************************************************/
+   protected Map<Pair<String, Serializable>, QRecord> getExistingRecordsByForeignKey
+   (
+      RunBackendStepInput runBackendStepInput,
+      String destinationTableForeignKeyField,
+      String destinationTableName,
+      List<Serializable> sourceKeyList
+   ) throws QException;
+
+
+   /*******************************************************************************
+    ** Overridable point where you can, for example, keys in the existingRecordsMap
+    ** with different fieldNames from the destinationTable.
+    **
+    ** Note, if you're overriding this method, you'll likely also want & need to
+    ** override getExistingRecord.
+    *******************************************************************************/
+   protected Map<Pair<String, Serializable>, QRecord> buildExistingRecordsMap
+   (
+      String destinationTableForeignKeyField,
+      List<QRecord> existingRecordList
+   );
+
+   /*******************************************************************************
+    ** Given the map of existingRecordsByForeignKey (as built by
+    ** getExistingRecordsByForeignKey which calls buildExistingRecordsMap),
+    ** get one record from that map, for a given key-value from a source record.
+    **
+    ** The destinationForeignKeyField is given as advice if needed (e.g., to see its type)
+    *******************************************************************************/
+   protected QRecord getExistingRecord
+   (
+      Map<Pair<String, Serializable>, QRecord> existingRecordsByForeignKey,
+      QFieldMetaData destinationForeignKeyField,
+      Serializable sourceKeyValue
+   );
+
+----
+

docs/index.adoc

@@ -36,10 +36,9 @@ include::misc/ProcessBackendSteps.adoc[leveloffset=+1]
 === Table Customizers
 #todo#
 
-== QQQ Actions
+== QQQ Core Actions
 include::actions/QueryAction.adoc[leveloffset=+1]
 
-=== GetAction
 include::actions/GetAction.adoc[leveloffset=+1]
 
 === CountAction
@@ -48,7 +47,6 @@ include::actions/GetAction.adoc[leveloffset=+1]
 === AggregateAction
 #todo#
 
-=== InsertAction
 include::actions/InsertAction.adoc[leveloffset=+1]
 
 === UpdateAction
@@ -60,4 +58,6 @@ include::actions/InsertAction.adoc[leveloffset=+1]
 === AuditAction
 #todo#
 
+== QQQ Default Implementations
+include::implementations/TableSync.adoc[leveloffset=+1]
 // later... include::actions/RenderTemplateAction.adoc[leveloffset=+1]