From e3423c7786dc7143eb3f8cd6df2f1d7d700bee90 Mon Sep 17 00:00:00 2001
From: Nadja Reitzenstein <me@dequbed.space>
Date: Sun, 24 Jul 2022 17:51:12 +0200
Subject: [PATCH] Improve error messages on missing config

---
 bffhd/config/dhall.rs | 26 +++++++++++-----------
 bffhd/config/mod.rs   | 52 ++++++++++++++++++++++++++++++++++++++-----
 bin/bffhd/main.rs     |  2 +-
 3 files changed, 60 insertions(+), 20 deletions(-)

diff --git a/bffhd/config/dhall.rs b/bffhd/config/dhall.rs
index 8e3e873..b933a0b 100644
--- a/bffhd/config/dhall.rs
+++ b/bffhd/config/dhall.rs
@@ -12,8 +12,8 @@ use crate::authorization::roles::Role;
 use crate::capnp::{Listen, TlsListen};
 use crate::logging::LogConfig;
 
-use std::path::Path;
 use miette::IntoDiagnostic;
+use std::path::Path;
 
 #[derive(Debug)]
 struct DhallConfig<'a> {
@@ -36,23 +36,23 @@ pub struct MachineDescription {
 
     /// An optional description of the Machine.
     #[serde(
-    default,
-    skip_serializing_if = "Option::is_none",
-    deserialize_with = "deser_option"
+        default,
+        skip_serializing_if = "Option::is_none",
+        deserialize_with = "deser_option"
     )]
     pub description: Option<String>,
 
     #[serde(
-    default,
-    skip_serializing_if = "Option::is_none",
-    deserialize_with = "deser_option"
+        default,
+        skip_serializing_if = "Option::is_none",
+        deserialize_with = "deser_option"
     )]
     pub wiki: Option<String>,
 
     #[serde(
-    default,
-    skip_serializing_if = "Option::is_none",
-    deserialize_with = "deser_option"
+        default,
+        skip_serializing_if = "Option::is_none",
+        deserialize_with = "deser_option"
     )]
     pub category: Option<String>,
 
@@ -111,9 +111,9 @@ pub struct ModuleConfig {
 }
 
 pub(crate) fn deser_option<'de, D, T>(d: D) -> std::result::Result<Option<T>, D::Error>
-    where
-        D: serde::Deserializer<'de>,
-        T: serde::Deserialize<'de>,
+where
+    D: serde::Deserializer<'de>,
+    T: serde::Deserialize<'de>,
 {
     Ok(T::deserialize(d).ok())
 }
diff --git a/bffhd/config/mod.rs b/bffhd/config/mod.rs
index 3adabb9..dfce376 100644
--- a/bffhd/config/mod.rs
+++ b/bffhd/config/mod.rs
@@ -1,10 +1,50 @@
-mod dhall;
-pub use dhall::read_config_file as read;
-pub use dhall::{Config, ModuleConfig, MachineDescription};
+use std::path::Path;
+
+use miette::Diagnostic;
+use thiserror::Error;
+
 pub(crate) use dhall::deser_option;
+pub use dhall::{Config, MachineDescription, ModuleConfig};
+mod dhall;
 
-struct ConfigBuilder;
-impl ConfigBuilder {
-
+#[derive(Debug, Error, Diagnostic)]
+pub enum ConfigError {
+    #[error("The config file '{0}' does not exist or is not readable")]
+    #[diagnostic(
+        code(config::notfound),
+        help("Make sure the config file and the directory it's in are readable by the user running bffh")
+    )]
+    NotFound(String),
+    #[error("The path '{0}' does not point to a file")]
+    #[diagnostic(
+        code(config::notafile),
+        help("The config must be a file in the dhall format")
+    )]
+    NotAFile(String),
+    #[error("failed to parse config: {0}")]
+    #[diagnostic(code(config::parse))]
+    Parse(
+        #[from]
+        #[source]
+        serde_dhall::Error,
+    ),
 }
 
+pub fn read(file: impl AsRef<Path>) -> Result<Config, ConfigError> {
+    let path = file.as_ref();
+    if !path.exists() {
+        return Err(ConfigError::NotFound(path.to_string_lossy().to_string()));
+    }
+    if !path.is_file() {
+        return Err(ConfigError::NotAFile(path.to_string_lossy().to_string()));
+    }
+    let mut config = dhall::read_config_file(file)?;
+    for (envvar, value) in std::env::vars() {
+        match envvar.as_str() {
+            // Do things like this?
+            // "BFFH_LOG" => config.logging.filter = Some(value),
+            _ => {}
+        }
+    }
+    Ok(config)
+}
diff --git a/bin/bffhd/main.rs b/bin/bffhd/main.rs
index d52cbca..fff25b7 100644
--- a/bin/bffhd/main.rs
+++ b/bin/bffhd/main.rs
@@ -135,7 +135,7 @@ fn main() -> miette::Result<()> {
         }
     }
 
-    let mut config = config::read(&PathBuf::from_str(configpath).unwrap()).unwrap();
+    let mut config = config::read(&PathBuf::from_str(configpath).unwrap())?;
 
     if matches.is_present("dump") {
         return Err(miette::miette!("DB Dumping is currently not implemented, except for the users db, using `--dump-users`"));