more xdg cleanup and encryption parameter improvements

Have a single common function to get the BaseDirectories
instance and a wrapper for `find()` and `place()` which
wrap the error with some context.

Signed-off-by: Wolfgang Bumiller <w.bumiller@proxmox.com>

src/bin/proxmox_backup_client/key.rs

@@ -1,9 +1,8 @@
 use std::path::PathBuf;
 
-use anyhow::{bail, format_err, Context, Error};
+use anyhow::{bail, format_err, Error};
 use chrono::{Local, TimeZone};
 use serde::{Deserialize, Serialize};
-use xdg::BaseDirectories;
 
 use proxmox::api::api;
 use proxmox::api::cli::{CliCommand, CliCommandMap};
@@ -16,29 +15,22 @@ use proxmox_backup::backup::{
 use proxmox_backup::tools;
 
 pub const DEFAULT_ENCRYPTION_KEY_FILE_NAME: &str = "encryption-key.json";
+pub const MASTER_PUBKEY_FILE_NAME: &str = "master-public.pem";
 
-pub fn master_pubkey_path() -> Result<PathBuf, Error> {
-    let base = BaseDirectories::with_prefix("proxmox-backup")?;
+pub fn find_master_pubkey() -> Result<Option<PathBuf>, Error> {
+    super::find_xdg_file(MASTER_PUBKEY_FILE_NAME, "main public key file")
+}
 
-    // usually $HOME/.config/proxmox-backup/master-public.pem
-    let path = base.place_config_file("master-public.pem")?;
-
-    Ok(path)
+pub fn place_master_pubkey() -> Result<PathBuf, Error> {
+    super::place_xdg_file(MASTER_PUBKEY_FILE_NAME, "main public key file")
 }
 
 pub fn find_default_encryption_key() -> Result<Option<PathBuf>, Error> {
-    BaseDirectories::with_prefix("proxmox-backup")
-        .map(|base| base.find_config_file(DEFAULT_ENCRYPTION_KEY_FILE_NAME))
-        .with_context(|| "error searching for default encryption key file")
+    super::find_xdg_file(DEFAULT_ENCRYPTION_KEY_FILE_NAME, "default encryption key file")
 }
 
 pub fn place_default_encryption_key() -> Result<PathBuf, Error> {
-    BaseDirectories::with_prefix("proxmox-backup")
-        .map_err(Error::from)
-        .and_then(|base| {
-            base.place_config_file(DEFAULT_ENCRYPTION_KEY_FILE_NAME).map_err(Error::from)
-        })
-        .with_context(|| "failed to place default encryption key file in xdg home")
+    super::place_xdg_file(DEFAULT_ENCRYPTION_KEY_FILE_NAME, "default encryption key file")
 }
 
 pub fn get_encryption_key_password() -> Result<Vec<u8>, Error> {
@@ -216,7 +208,7 @@ fn import_master_pubkey(path: String) -> Result<(), Error> {
         bail!("Unable to decode PEM data - {}", err);
     }
 
-    let target_path = master_pubkey_path()?;
+    let target_path = place_master_pubkey()?;
 
     replace_file(&target_path, &pem_data, CreateOptions::new())?;
 

src/bin/proxmox_backup_client/mod.rs

@@ -1,3 +1,5 @@
+use anyhow::{Context, Error};
+
 mod benchmark;
 pub use benchmark::*;
 mod mount;
@@ -8,3 +10,30 @@ mod catalog;
 pub use catalog::*;
 
 pub mod key;
+
+pub fn base_directories() -> Result<xdg::BaseDirectories, Error> {
+    xdg::BaseDirectories::with_prefix("proxmox-backup").map_err(Error::from)
+}
+
+/// Convenience helper for better error messages:
+pub fn find_xdg_file(
+    file_name: impl AsRef<std::path::Path>,
+    description: &'static str,
+) -> Result<Option<std::path::PathBuf>, Error> {
+    let file_name = file_name.as_ref();
+    base_directories()
+        .map(|base| base.find_config_file(file_name))
+        .with_context(|| format!("error searching for {}", description))
+}
+
+pub fn place_xdg_file(
+    file_name: impl AsRef<std::path::Path>,
+    description: &'static str,
+) -> Result<std::path::PathBuf, Error> {
+    let file_name = file_name.as_ref();
+    base_directories()
+        .and_then(|base| {
+            base.place_config_file(file_name).map_err(Error::from)
+        })
+        .with_context(|| format!("failed to place {} in xdg home", description))
+}