Merge pull request #40 from AnGREATern/env-st-flds

Add parsing as env to config

Author: unikmhz

Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "uxum"
-version = "0.7.1"
+version = "0.7.2"
 authors = ["Alex Unigovsky <unik@devrandom.ru>"]
 license = "MIT OR Apache-2.0"
 edition = "2021"
@@ -75,6 +75,7 @@ problemdetails = { version = "0.5", features = ["axum"] }
 prometheus = "0.14"
 prost = { version = "0.13", optional = true }
 recloser = "1.1"
+regex = "1.11.2"
 reqwest = { version = "0.12", default-features = false, features = ["charset", "hickory-dns", "http2", "json", "macos-system-configuration", "rustls-tls-native-roots"] }
 reqwest-middleware = { version = "0.4", features = ["multipart", "json"] }
 reqwest-tracing = { version = "0.5.7", features = ["opentelemetry_0_29"] }

examples/inner_service/config.yaml

@@ -21,9 +21,10 @@ logging:
       flatten_metadata: true
       current_span: true
       static_fields:
-        env: dev
-        something: something
+        user: $USER
+        something: $PATH, lol $KEK and $USER ($USER) 
         other: 42
+      parse_env_in_static: true
 metrics:
   labels:
     env: example

src/logging/json.rs

@@ -1,7 +1,8 @@
 //! Custom JSON formatter and writer for use in logging.
 
-use std::{borrow::Cow, collections::BTreeMap, fmt, io, marker::PhantomData};
+use std::{borrow::Cow, collections::BTreeMap, env, fmt, io, marker::PhantomData, sync::LazyLock};
 
+use regex::Regex;
 use serde::{ser::SerializeMap, Deserialize, Serialize, Serializer};
 use serde_json::{Serializer as JsonSerializer, Value};
 use tracing::{Event, Subscriber};
@@ -16,6 +17,9 @@ use tracing_subscriber::{
     registry::{LookupSpan, SpanRef},
 };
 
+static ENV_VAR_REGEX: LazyLock<Regex> =
+    LazyLock::new(|| Regex::new(r"\$([A-Za-z_][A-Za-z0-9_]*)").unwrap());
+
 /// Custom names JSON keys.
 #[derive(Clone, Debug, Deserialize, PartialEq, Serialize)]
 #[non_exhaustive]
@@ -434,7 +438,28 @@ impl<T> ExtensibleJsonFormat<T> {
     }
 
     /// Add static fields to generated JSON objects.
-    pub(crate) fn with_static_fields(self, static_fields: BTreeMap<String, Value>) -> Self {
+    pub(crate) fn with_static_fields(
+        self,
+        mut static_fields: BTreeMap<String, Value>,
+        parse_env: bool,
+    ) -> Self {
+        if parse_env {
+            let expand_env_vars = |input: &str| -> Value {
+                ENV_VAR_REGEX
+                    .replace_all(input, |caps: &regex::Captures<'_>| {
+                        let var_name = &caps[1];
+                        env::var(var_name).unwrap_or_else(|_| format!("${}", var_name))
+                    })
+                    .into()
+            };
+
+            for val in static_fields.values_mut() {
+                if let Some(value) = val.as_str() {
+                    *val = expand_env_vars(value);
+                }
+            }
+        }
+
         Self {
             static_fields,
             ..self

src/logging/mod.rs

@@ -159,6 +159,7 @@ impl LoggingSubscriberConfig {
                 current_span,
                 ref static_fields,
                 ref key_names,
+                parse_env_in_static,
             } => {
                 let json_fmt = ExtensibleJsonFormat::new()
                     .with_target(self.print.target)
@@ -169,7 +170,7 @@ impl LoggingSubscriberConfig {
                     .with_thread_ids(self.print.thread_id)
                     .flatten_event(flatten_metadata)
                     .with_current_span(current_span)
-                    .with_static_fields(static_fields.clone())
+                    .with_static_fields(static_fields.clone(), parse_env_in_static)
                     .with_key_names(*key_names.clone());
                 layer.json().event_format(json_fmt).boxed()
             }
@@ -230,6 +231,9 @@ pub enum LoggingFormat {
         /// Custom names for JSON keys.
         #[serde(default)]
         key_names: Box<JsonKeyNames>,
+        /// Parse environment variables in static fields
+        #[serde(default)]
+        parse_env_in_static: bool,
     },
 }