From 31d4d1e233c1572bd5715bde8c58477d8bfaa285 Mon Sep 17 00:00:00 2001
From: Christian Schwarz <christian@neon.tech>
Date: Fri, 5 Apr 2024 10:49:31 +0200
Subject: [PATCH] env_config from PR #6125

---
 control_plane/src/background_process.rs | 14 +++++++-
 libs/utils/src/env_config.rs            | 48 +++++++++++++++++++++++++
 libs/utils/src/lib.rs                   |  1 +
 libs/utils/src/logging.rs               |  8 ++++-
 4 files changed, 69 insertions(+), 2 deletions(-)
 create mode 100644 libs/utils/src/env_config.rs

diff --git a/control_plane/src/background_process.rs b/control_plane/src/background_process.rs
index 2fced7d778..fbd739ac9e 100644
--- a/control_plane/src/background_process.rs
+++ b/control_plane/src/background_process.rs
@@ -86,7 +86,10 @@ where
         .stdout(process_log_file)
         .stderr(same_file_for_stderr)
         .args(args);
-    let filled_cmd = fill_remote_storage_secrets_vars(fill_rust_env_vars(background_command));
+
+    let filled_cmd = fill_env_vars_prefixed_neon(fill_remote_storage_secrets_vars(
+        fill_rust_env_vars(background_command),
+    ));
     filled_cmd.envs(envs);
 
     let pid_file_to_check = match &initial_pid_file {
@@ -268,6 +271,15 @@ fn fill_remote_storage_secrets_vars(mut cmd: &mut Command) -> &mut Command {
     cmd
 }
 
+fn fill_env_vars_prefixed_neon(mut cmd: &mut Command) -> &mut Command {
+    for (var, val) in std::env::vars() {
+        if var.starts_with("NEON_") {
+            cmd = cmd.env(var, val);
+        }
+    }
+    cmd
+}
+
 /// Add a `pre_exec` to the cmd that, inbetween fork() and exec(),
 /// 1. Claims a pidfile with a fcntl lock on it and
 /// 2. Sets up the pidfile's file descriptor so that it (and the lock)
diff --git a/libs/utils/src/env_config.rs b/libs/utils/src/env_config.rs
new file mode 100644
index 0000000000..823a49796c
--- /dev/null
+++ b/libs/utils/src/env_config.rs
@@ -0,0 +1,48 @@
+use std::{fmt::Display, str::FromStr};
+
+pub fn var<V, E, D>(varname: &str, default: D) -> V
+where
+    V: FromStr<Err = E>,
+    E: Display,
+    D: FnOnce() -> V,
+{
+    match std::env::var(varname) {
+        Ok(s) => s
+            .parse()
+            .map_err(|e| format!("failed to parse env var {varname}: {e:#}"))
+            .unwrap(),
+        Err(std::env::VarError::NotPresent) => default(),
+        Err(std::env::VarError::NotUnicode(_)) => {
+            panic!("env var {varname} is not unicode")
+        }
+    }
+}
+
+pub struct Bool(bool);
+
+impl Bool {
+    pub const fn new_const<const V: bool>() -> Self {
+        Bool(V)
+    }
+}
+
+impl FromStr for Bool {
+    type Err = String;
+
+    fn from_str(s: &str) -> Result<Self, Self::Err> {
+        if let Ok(b) = s.parse() {
+            return Ok(Bool(b));
+        }
+        Ok(Bool(match s {
+            "0" => false,
+            "1" => true,
+            _ => return Err(format!("not a bool, accepting 0|1|{}|{}", false, true)),
+        }))
+    }
+}
+
+impl Into<bool> for Bool {
+    fn into(self) -> bool {
+        self.0
+    }
+}
diff --git a/libs/utils/src/lib.rs b/libs/utils/src/lib.rs
index 04ce0626c8..bd04eeea05 100644
--- a/libs/utils/src/lib.rs
+++ b/libs/utils/src/lib.rs
@@ -27,6 +27,7 @@ pub mod auth;
 pub mod id;
 
 mod hex;
+pub mod env_config;
 pub use hex::Hex;
 
 // http endpoint utils
diff --git a/libs/utils/src/logging.rs b/libs/utils/src/logging.rs
index f7b73dc984..d9531d0438 100644
--- a/libs/utils/src/logging.rs
+++ b/libs/utils/src/logging.rs
@@ -1,10 +1,16 @@
-use std::str::FromStr;
+use std::{
+    io::BufWriter,
+    str::FromStr,
+    sync::{Arc, Mutex},
+};
 
 use anyhow::Context;
 use metrics::{IntCounter, IntCounterVec};
 use once_cell::sync::Lazy;
 use strum_macros::{EnumString, EnumVariantNames};
 
+use super::env_config;
+
 #[derive(EnumString, EnumVariantNames, Eq, PartialEq, Debug, Clone, Copy)]
 #[strum(serialize_all = "snake_case")]
 pub enum LogFormat {