fix: better logging for iroh-dns-server (n0-computer#2195)

## Description

Logs the database file path on start, and adds context to some errors if
things fail.

## Notes & open questions

<!-- Any notes, remarks or open questions you have to make about the PR.
-->

## Change checklist

- [ ] Self-review.
- [ ] Documentation updates if relevant.
- [ ] Tests if relevant.

iroh-dns-server/src/config.rs

@@ -1,13 +1,15 @@
 //! Configuration for the server
 
-use anyhow::{anyhow, Context, Result};
-use serde::{Deserialize, Serialize};
 use std::{
     env,
     net::{IpAddr, Ipv4Addr, SocketAddr},
     path::{Path, PathBuf},
 };
 
+use anyhow::{anyhow, Context, Result};
+use serde::{Deserialize, Serialize};
+use tracing::info;
+
 use crate::{
     dns::DnsConfig,
     http::{CertMode, HttpConfig, HttpsConfig},
@@ -62,6 +64,10 @@ impl MetricsConfig {
 impl Config {
     /// Load the config from a file.
     pub async fn load(path: impl AsRef<Path>) -> Result<Config> {
+        info!(
+            "loading config file from {}",
+            path.as_ref().to_string_lossy()
+        );
         let s = tokio::fs::read_to_string(path.as_ref())
             .await
             .with_context(|| format!("failed to read {}", path.as_ref().to_string_lossy()))?;

iroh-dns-server/src/store/signed_packets.rs

@@ -1,9 +1,10 @@
 use std::path::Path;
 
-use anyhow::Result;
+use anyhow::{Context, Result};
 use iroh_metrics::inc;
 use pkarr::SignedPacket;
 use redb::{backends::InMemoryBackend, Database, ReadableTable, TableDefinition};
+use tracing::info;
 
 use crate::{metrics::Metrics, util::PublicKeyBytes};
 
@@ -18,14 +19,24 @@ pub struct SignedPacketStore {
 
 impl SignedPacketStore {
     pub fn persistent(path: impl AsRef<Path>) -> Result<Self> {
-        if let Some(parent) = path.as_ref().parent() {
-            std::fs::create_dir_all(parent)?;
+        let path = path.as_ref();
+        info!("loading packet database from {}", path.to_string_lossy());
+        if let Some(parent) = path.parent() {
+            std::fs::create_dir_all(parent).with_context(|| {
+                format!(
+                    "failed to create database directory at {}",
+                    path.to_string_lossy()
+                )
+            })?;
         }
-        let db = Database::builder().create(path)?;
+        let db = Database::builder()
+            .create(path)
+            .context("failed to open packet database")?;
         Self::open(db)
     }
 
     pub fn in_memory() -> Result<Self> {
+        info!("using in-memory packet database");
         let db = Database::builder().create_with_backend(InMemoryBackend::new())?;
         Self::open(db)
     }