chore(config): log component graph when there's an error (#21669)

* chore(config): add message to help debug problematic config

* fmt

* clippy fixes

* update test

lib/vector-core/src/config/mod.rs

@@ -30,6 +30,7 @@ pub const MEMORY_BUFFER_DEFAULT_MAX_EVENTS: NonZeroUsize =
 // This enum should be kept alphabetically sorted as the bitmask value is used when
 // sorting sources by data type in the GraphQL API.
 #[bitmask(u8)]
+#[bitmask_config(flags_iter)]
 pub enum DataType {
     Log,
     Metric,
@@ -38,11 +39,11 @@ pub enum DataType {
 
 impl fmt::Display for DataType {
     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
-        let mut t = Vec::new();
-        self.contains(DataType::Log).then(|| t.push("Log"));
-        self.contains(DataType::Metric).then(|| t.push("Metric"));
-        self.contains(DataType::Trace).then(|| t.push("Trace"));
-        f.write_str(&t.join(","))
+        f.debug_list()
+            .entries(
+                Self::flags().filter_map(|&(name, value)| self.contains(value).then_some(name)),
+            )
+            .finish()
     }
 }
 
@@ -191,6 +192,24 @@ impl SourceOutput {
     }
 }
 
+fn fmt_helper(
+    f: &mut fmt::Formatter<'_>,
+    maybe_port: Option<&String>,
+    data_type: DataType,
+) -> fmt::Result {
+    match maybe_port {
+        Some(port) => write!(f, "port: \"{port}\",",),
+        None => write!(f, "port: None,"),
+    }?;
+    write!(f, " types: {data_type}")
+}
+
+impl fmt::Display for SourceOutput {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        fmt_helper(f, self.port.as_ref(), self.ty)
+    }
+}
+
 #[derive(Debug, Clone, PartialEq)]
 pub struct TransformOutput {
     pub port: Option<String>,
@@ -203,6 +222,12 @@ pub struct TransformOutput {
     pub log_schema_definitions: HashMap<OutputId, schema::Definition>,
 }
 
+impl fmt::Display for TransformOutput {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        fmt_helper(f, self.port.as_ref(), self.ty)
+    }
+}
+
 impl TransformOutput {
     /// Create a `TransformOutput` of the given data type that contains multiple [`schema::Definition`]s.
     /// Designed for use in transforms.

src/config/graph.rs

@@ -1,10 +1,10 @@
-use indexmap::{set::IndexSet, IndexMap};
-use std::collections::{HashMap, HashSet, VecDeque};
-
 use super::{
     schema, ComponentKey, DataType, OutputId, SinkOuter, SourceOuter, SourceOutput, TransformOuter,
     TransformOutput,
 };
+use indexmap::{set::IndexSet, IndexMap};
+use std::collections::{HashMap, HashSet, VecDeque};
+use std::fmt;
 
 #[derive(Debug, Clone)]
 pub enum Node {
@@ -20,6 +20,33 @@ pub enum Node {
     },
 }
 
+impl fmt::Display for Node {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        match self {
+            Node::Source { outputs } => {
+                write!(f, "component_kind: source\n  outputs:")?;
+                for output in outputs {
+                    write!(f, "\n    {}", output)?;
+                }
+                Ok(())
+            }
+            Node::Transform { in_ty, outputs } => {
+                write!(
+                    f,
+                    "component_kind: source\n  input_types: {in_ty}\n  outputs:"
+                )?;
+                for output in outputs {
+                    write!(f, "\n    {}", output)?;
+                }
+                Ok(())
+            }
+            Node::Sink { ty } => {
+                write!(f, "component_kind: sink\n  types: {ty}")
+            }
+        }
+    }
+}
+
 #[derive(Debug, Clone)]
 struct Edge {
     from: OutputId,
@@ -139,9 +166,16 @@ impl Graph {
                 Some(Node::Sink { .. }) => "sink",
                 _ => panic!("only transforms and sinks have inputs"),
             };
+            info!(
+                "Available components:\n{}",
+                self.nodes
+                    .iter()
+                    .map(|(key, node)| format!("\"{}\":\n  {}", key, node))
+                    .collect::<Vec<_>>()
+                    .join("\n")
+            );
             Err(format!(
-                "Input \"{}\" for {} \"{}\" doesn't match any components.",
-                from, output_type, to
+                "Input \"{from}\" for {output_type} \"{to}\" doesn't match any components.",
             ))
         }
     }
@@ -510,7 +544,7 @@ mod test {
 
         assert_eq!(
             Err(vec![
-                "Data type mismatch between in (Log) and out (Metric)".into()
+                "Data type mismatch between in ([\"Log\"]) and out ([\"Metric\"])".into()
             ]),
             graph.typecheck()
         );