feat: Migrate LogSchema::host_key to new lookup code (vectordotdev#17972)

This part of vectordotdev#13033.

Summary of these changes:
* LogSchema::host_key is now an `OptionalValuePath`
* `host_key`s that appear in configs are now also `OptionalValuePath`s
* There should be no `unwrap()` calls outside of tests.

---------

Co-authored-by: Stephen Wakely <[email protected]>

Author: pront

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

@@ -55,7 +55,7 @@ pub struct LogSchema {
     /// This field will generally represent a real host, or container, that generated the message,
     /// but is somewhat source-dependent.
     #[serde(default = "LogSchema::default_host_key")]
-    host_key: String,
+    host_key: OptionalValuePath,
 
     /// The name of the event field to set the source identifier in.
     ///
@@ -92,8 +92,8 @@ impl LogSchema {
         OptionalValuePath::new("timestamp")
     }
 
-    fn default_host_key() -> String {
-        String::from("host")
+    fn default_host_key() -> OptionalValuePath {
+        OptionalValuePath::new("host")
     }
 
     fn default_source_type_key() -> OptionalValuePath {
@@ -121,8 +121,8 @@ impl LogSchema {
         self.timestamp_key.path.as_ref()
     }
 
-    pub fn host_key(&self) -> &str {
-        &self.host_key
+    pub fn host_key(&self) -> Option<&OwnedValuePath> {
+        self.host_key.path.as_ref()
     }
 
     pub fn source_type_key(&self) -> Option<&OwnedValuePath> {
@@ -141,8 +141,8 @@ impl LogSchema {
         self.timestamp_key = OptionalValuePath { path: v };
     }
 
-    pub fn set_host_key(&mut self, v: String) {
-        self.host_key = v;
+    pub fn set_host_key(&mut self, path: Option<OwnedValuePath>) {
+        self.host_key = OptionalValuePath { path };
     }
 
     pub fn set_source_type_key(&mut self, path: Option<OwnedValuePath>) {
@@ -169,7 +169,7 @@ impl LogSchema {
             {
                 errors.push("conflicting values for 'log_schema.host_key' found".to_owned());
             } else {
-                self.set_host_key(other.host_key().to_string());
+                self.set_host_key(other.host_key().cloned());
             }
             if self.message_key() != LOG_SCHEMA_DEFAULT.message_key()
                 && self.message_key() != other.message_key()

lib/vector-core/src/event/log_event.rs

@@ -458,7 +458,7 @@ impl LogEvent {
     pub fn host_path(&self) -> Option<String> {
         match self.namespace() {
             LogNamespace::Vector => self.find_key_by_meaning("host"),
-            LogNamespace::Legacy => Some(log_schema().host_key().to_owned()),
+            LogNamespace::Legacy => log_schema().host_key().map(ToString::to_string),
         }
     }
 
@@ -505,7 +505,9 @@ impl LogEvent {
     pub fn get_host(&self) -> Option<&Value> {
         match self.namespace() {
             LogNamespace::Vector => self.get_by_meaning("host"),
-            LogNamespace::Legacy => self.get((PathPrefix::Event, log_schema().host_key())),
+            LogNamespace::Legacy => log_schema()
+                .host_key()
+                .and_then(|key| self.get((PathPrefix::Event, key))),
         }
     }
 

lib/vector-lookup/src/lookup_v2/optional_path.rs

@@ -91,3 +91,11 @@ impl From<OwnedValuePath> for OptionalValuePath {
         Self { path: Some(path) }
     }
 }
+
+impl From<Option<OwnedValuePath>> for OptionalValuePath {
+    fn from(value: Option<OwnedValuePath>) -> Self {
+        value.map_or(OptionalValuePath::none(), |path| {
+            OptionalValuePath::from(path)
+        })
+    }
+}

src/config/mod.rs

@@ -843,7 +843,10 @@ mod tests {
         )
         .unwrap();
 
-        assert_eq!("host", config.global.log_schema.host_key().to_string());
+        assert_eq!(
+            "host",
+            config.global.log_schema.host_key().unwrap().to_string()
+        );
         assert_eq!(
             "message",
             config.global.log_schema.message_key().to_string()
@@ -879,7 +882,10 @@ mod tests {
         )
         .unwrap();
 
-        assert_eq!("this", config.global.log_schema.host_key().to_string());
+        assert_eq!(
+            "this",
+            config.global.log_schema.host_key().unwrap().to_string()
+        );
         assert_eq!("that", config.global.log_schema.message_key().to_string());
         assert_eq!(
             "then",

src/sinks/datadog/metrics/encoder.rs

@@ -385,7 +385,10 @@ fn sketch_to_proto_message(
     let name = get_namespaced_name(metric, default_namespace);
     let ts = encode_timestamp(metric.timestamp());
     let mut tags = metric.tags().cloned().unwrap_or_default();
-    let host = tags.remove(log_schema.host_key()).unwrap_or_default();
+    let host = log_schema
+        .host_key()
+        .map(|key| tags.remove(key.to_string().as_str()).unwrap_or_default())
+        .unwrap_or_default();
     let tags = encode_tags(&tags);
 
     let cnt = ddsketch.count() as i64;
@@ -497,7 +500,10 @@ fn generate_series_metrics(
     let name = get_namespaced_name(metric, default_namespace);
 
     let mut tags = metric.tags().cloned().unwrap_or_default();
-    let host = tags.remove(log_schema.host_key());
+    let host = log_schema
+        .host_key()
+        .map(|key| tags.remove(key.to_string().as_str()).unwrap_or_default());
+
     let source_type_name = tags.remove("source_type_name");
     let device = tags.remove("device");
     let ts = encode_timestamp(metric.timestamp());

src/sinks/datadog/traces/sink.rs

@@ -7,6 +7,8 @@ use futures_util::{
 };
 use tokio::sync::oneshot::{channel, Sender};
 use tower::Service;
+use vrl::path::PathPrefix;
+
 use vector_core::{
     config::log_schema,
     event::Event,
@@ -15,11 +17,13 @@ use vector_core::{
     stream::{BatcherSettings, DriverResponse},
 };
 
-use super::service::TraceApiRequest;
 use crate::{
     internal_events::DatadogTracesEncodingError,
     sinks::{datadog::traces::request_builder::DatadogTracesRequestBuilder, util::SinkBuilderExt},
 };
+
+use super::service::TraceApiRequest;
+
 #[derive(Default)]
 struct EventPartitioner;
 
@@ -51,9 +55,10 @@ impl Partitioner for EventPartitioner {
             Event::Trace(t) => PartitionKey {
                 api_key: item.metadata().datadog_api_key(),
                 env: t.get("env").map(|s| s.to_string_lossy().into_owned()),
-                hostname: t
-                    .get(log_schema().host_key())
-                    .map(|s| s.to_string_lossy().into_owned()),
+                hostname: log_schema().host_key().and_then(|key| {
+                    t.get((PathPrefix::Event, key))
+                        .map(|s| s.to_string_lossy().into_owned())
+                }),
                 agent_version: t
                     .get("agent_version")
                     .map(|s| s.to_string_lossy().into_owned()),

src/sinks/humio/logs.rs

@@ -3,7 +3,7 @@ use lookup::lookup_v2::OptionalValuePath;
 use vector_common::sensitive_string::SensitiveString;
 use vector_config::configurable_component;
 
-use super::host_key;
+use super::config_host_key;
 use crate::sinks::splunk_hec::common::config_timestamp_key;
 use crate::{
     codecs::EncodingConfig,
@@ -74,8 +74,8 @@ pub struct HumioLogsConfig {
     /// By default, the [global `log_schema.host_key` option][global_host_key] is used.
     ///
     /// [global_host_key]: https://vector.dev/docs/reference/configuration/global-options/#log_schema.host_key
-    #[serde(default = "host_key")]
-    pub(super) host_key: String,
+    #[serde(default = "config_host_key")]
+    pub(super) host_key: OptionalValuePath,
 
     /// Event fields to be added to Humio’s extra fields.
     ///
@@ -154,7 +154,7 @@ impl GenerateConfig for HumioLogsConfig {
             event_type: None,
             indexed_fields: vec![],
             index: None,
-            host_key: host_key(),
+            host_key: config_host_key(),
             compression: Compression::default(),
             request: TowerRequestConfig::default(),
             batch: BatchConfig::default(),
@@ -231,6 +231,7 @@ mod integration_tests {
     use serde::Deserialize;
     use serde_json::{json, Value as JsonValue};
     use tokio::time::Duration;
+    use vrl::path::PathPrefix;
 
     use super::*;
     use crate::{
@@ -262,14 +263,14 @@ mod integration_tests {
         let message = random_string(100);
         let host = "192.168.1.1".to_string();
         let mut event = LogEvent::from(message.clone());
-        event.insert(log_schema().host_key(), host.clone());
+        event.insert(
+            (PathPrefix::Event, log_schema().host_key().unwrap()),
+            host.clone(),
+        );
 
         let ts = Utc.timestamp_nanos(Utc::now().timestamp_millis() * 1_000_000 + 132_456);
         event.insert(
-            (
-                lookup::PathPrefix::Event,
-                log_schema().timestamp_key().unwrap(),
-            ),
+            (PathPrefix::Event, log_schema().timestamp_key().unwrap()),
             ts,
         );
 
@@ -387,7 +388,9 @@ mod integration_tests {
             source: None,
             encoding: JsonSerializerConfig::default().into(),
             event_type: None,
-            host_key: log_schema().host_key().to_string(),
+            host_key: OptionalValuePath {
+                path: log_schema().host_key().cloned(),
+            },
             indexed_fields: vec![],
             index: None,
             compression: Compression::None,

src/sinks/humio/metrics.rs

@@ -9,7 +9,7 @@ use vector_config::configurable_component;
 use vector_core::sink::StreamSink;
 
 use super::{
-    host_key,
+    config_host_key,
     logs::{HumioLogsConfig, HOST},
 };
 use crate::{
@@ -86,8 +86,8 @@ pub struct HumioMetricsConfig {
     /// By default, the [global `log_schema.host_key` option][global_host_key] is used.
     ///
     /// [global_host_key]: https://vector.dev/docs/reference/configuration/global-options/#log_schema.host_key
-    #[serde(default = "host_key")]
-    host_key: String,
+    #[serde(default = "config_host_key")]
+    host_key: OptionalValuePath,
 
     /// Event fields to be added to Humio’s extra fields.
     ///

src/sinks/humio/mod.rs

@@ -1,6 +1,10 @@
+use lookup::lookup_v2::OptionalValuePath;
+
 pub mod logs;
 pub mod metrics;
 
-fn host_key() -> String {
-    crate::config::log_schema().host_key().to_string()
+pub fn config_host_key() -> OptionalValuePath {
+    OptionalValuePath {
+        path: crate::config::log_schema().host_key().cloned(),
+    }
 }

src/sinks/influxdb/logs.rs

@@ -4,12 +4,13 @@ use bytes::{Bytes, BytesMut};
 use futures::SinkExt;
 use http::{Request, Uri};
 use indoc::indoc;
+use vrl::value::Kind;
+
 use lookup::lookup_v2::{parse_value_path, OptionalValuePath};
 use lookup::{OwnedValuePath, PathPrefix};
 use vector_config::configurable_component;
 use vector_core::config::log_schema;
 use vector_core::schema;
-use vrl::value::Kind;
 
 use crate::{
     codecs::Transformer,
@@ -189,10 +190,8 @@ impl SinkConfig for InfluxDbLogsConfig {
             .host_key
             .clone()
             .and_then(|k| k.path)
-            .unwrap_or_else(|| {
-                parse_value_path(log_schema().host_key())
-                    .expect("global log_schema.host_key to be valid path")
-            });
+            .or(log_schema().host_key().cloned())
+            .expect("global log_schema.host_key to be valid path");
 
         let message_key = self
             .message_key
@@ -409,10 +408,10 @@ mod tests {
     use futures::{channel::mpsc, stream, StreamExt};
     use http::{request::Parts, StatusCode};
     use indoc::indoc;
+
     use lookup::owned_value_path;
     use vector_core::event::{BatchNotifier, BatchStatus, Event, LogEvent};
 
-    use super::*;
     use crate::{
         sinks::{
             influxdb::test_util::{assert_fields, split_line_protocol, ts},
@@ -427,6 +426,8 @@ mod tests {
         },
     };
 
+    use super::*;
+
     type Receiver = mpsc::Receiver<(Parts, bytes::Bytes)>;
 
     #[test]
@@ -880,16 +881,17 @@ mod tests {
 #[cfg(feature = "influxdb-integration-tests")]
 #[cfg(test)]
 mod integration_tests {
+    use std::sync::Arc;
+
     use chrono::Utc;
-    use codecs::BytesDeserializerConfig;
     use futures::stream;
+    use vrl::value;
+
+    use codecs::BytesDeserializerConfig;
     use lookup::{owned_value_path, path};
-    use std::sync::Arc;
     use vector_core::config::{LegacyKey, LogNamespace};
     use vector_core::event::{BatchNotifier, BatchStatus, Event, LogEvent};
-    use vrl::value;
 
-    use super::*;
     use crate::{
         config::SinkContext,
         sinks::influxdb::{
@@ -900,6 +902,8 @@ mod integration_tests {
         test_util::components::{run_and_assert_sink_compliance, HTTP_SINK_TAGS},
     };
 
+    use super::*;
+
     #[tokio::test]
     async fn influxdb2_logs_put_data() {
         let endpoint = address_v2();

src/sinks/splunk_hec/common/util.rs

@@ -132,8 +132,10 @@ pub fn build_uri(
     uri.parse::<Uri>()
 }
 
-pub fn host_key() -> String {
-    crate::config::log_schema().host_key().to_string()
+pub fn config_host_key() -> OptionalValuePath {
+    OptionalValuePath {
+        path: crate::config::log_schema().host_key().cloned(),
+    }
 }
 
 pub fn config_timestamp_key() -> OptionalValuePath {