martinzink commented on code in PR #2186:
URL: https://github.com/apache/nifi-minifi-cpp/pull/2186#discussion_r3339519653
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minifi_rust/minifi_native/src/api/processor_wrappers/flow_file_transform.rs:
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@@ -0,0 +1,184 @@
+use crate::api::InputStream;
+use crate::api::processor::{AdvancedProcessorFeatures, Processor};
+use
crate::api::processor_wrappers::utils::context_session_flowfile_bundle::ContextSessionFlowFileBundle;
+use crate::api::processor_wrappers::utils::flow_file_content::Content;
+use crate::api::property::{GetControllerService, GetProperty};
+use crate::api::raw_processor::{MultiThreadedTrigger, SingleThreadedTrigger};
+use crate::{
+ CalculateMetrics, Concurrent, Exclusive, GetAttribute, LogLevel, Logger,
MinifiError,
+ OnTriggerResult, ProcessContext, ProcessSession, Relationship, Schedule,
info,
+};
+use std::collections::HashMap;
+
+#[derive(Debug)]
+pub struct TransformedFlowFile<'a> {
+ target_relationship_name: &'static str,
+ new_content: Option<Content<'a>>,
+ attributes_to_add: HashMap<String, String>,
+}
+
+impl<'a> TransformedFlowFile<'a> {
+ pub fn route_without_changes(target_relationship: &Relationship) -> Self {
+ Self {
+ target_relationship_name: target_relationship.name,
+ new_content: None,
+ attributes_to_add: HashMap::new(),
+ }
+ }
+
+ pub fn new(
+ target_relationship: &Relationship,
+ new_content: Option<Vec<u8>>,
+ attributes_to_add: HashMap<String, String>,
+ ) -> Self {
+ Self {
+ target_relationship_name: target_relationship.name,
+ new_content: new_content.map(|b| Content::Buffer(b)),
+ attributes_to_add,
+ }
+ }
+
+ pub fn new_content(&'_ self) -> Option<&'_ Content<'_>> {
+ self.new_content.as_ref()
+ }
+
+ pub fn target_relationship(&self) -> &'static str {
+ self.target_relationship_name
+ }
+
+ pub fn attributes_to_add(&self) -> &HashMap<String, String> {
+ &self.attributes_to_add
+ }
+}
+
+pub trait FlowFileTransform {
+ fn transform<
+ 'a,
+ Context: GetProperty + GetControllerService + GetAttribute,
+ LoggerImpl: Logger,
+ >(
+ &self,
+ context: &Context,
+ input_stream: &'a mut dyn InputStream,
+ logger: &LoggerImpl,
+ ) -> Result<TransformedFlowFile<'a>, MinifiError>;
+}
+
+pub trait MutFlowFileTransform {
+ fn transform<
+ 'a,
+ Context: GetProperty + GetControllerService + GetAttribute,
+ LoggerImpl: Logger,
+ >(
+ &mut self,
+ context: &Context,
+ input_stream: &'a mut dyn InputStream,
+ logger: &LoggerImpl,
+ ) -> Result<TransformedFlowFile<'a>, MinifiError>;
+}
+
+pub struct FlowFileTransformProcessorType {}
+
+fn handle_transform<PC, PS, L, F>(
+ context: &mut PC,
+ session: &mut PS,
+ logger: &L,
+ mut transform_fn: F,
+) -> Result<OnTriggerResult, MinifiError>
+where
+ PC: ProcessContext,
+ PS: ProcessSession<FlowFile = PC::FlowFile>,
+ L: Logger,
+ F: for<'stream> FnMut(
+ &ContextSessionFlowFileBundle<'_, PC, PS>,
+ &'stream mut dyn InputStream,
+ ) -> Result<TransformedFlowFile<'stream>, MinifiError>,
+{
+ if let Some(mut flow_file) = session.get() {
+ let simple_context = ContextSessionFlowFileBundle::new(context,
session, Some(&flow_file));
+
+ let (attrs_to_add, relationship) = session.read_stream(&flow_file,
|input_stream| {
+ let transformed = transform_fn(&simple_context, input_stream)?;
+
+ info!(logger, "{:?}", transformed);
+ match transformed.new_content {
+ None => {}
+ Some(Content::Buffer(buffer)) => {
+ session.write(&flow_file, &buffer)?;
+ }
+ Some(Content::Stream(stream)) => {
+ session.write_lazy(&flow_file, stream)?;
+ }
+ };
+
+ Ok((
+ transformed.attributes_to_add,
+ transformed.target_relationship_name,
+ ))
+ })?;
+
+ for (k, v) in attrs_to_add {
+ session.set_attribute(&mut flow_file, &k, &v)?;
+ }
+
+ session.transfer(flow_file, relationship)?;
+ Ok(OnTriggerResult::Ok)
+ } else {
+ logger.log(LogLevel::Trace, format_args!("No flowfile to transform"));
+ Ok(OnTriggerResult::Yield)
+ }
+}
+
+impl<Implementation, L> MultiThreadedTrigger
+ for Processor<Implementation, FlowFileTransformProcessorType, Concurrent,
L>
+where
+ Implementation: Schedule + CalculateMetrics + FlowFileTransform +
AdvancedProcessorFeatures,
+ L: Logger,
+{
+ fn on_trigger<PC, PS>(
Review Comment:
Result of the transformation, it can (but not neccesary) modify the content,
add new attributes and route to a relationship.
Transformation takes place one by one.
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