client: allow storing the client token in a separate file

client/src/api/mod.rs

@@ -62,7 +62,7 @@ pub struct StructuredApiError {
 
 impl ApiClient {
     pub fn from_server_config(config: ServerConfig) -> Result<Self> {
-        let client = build_http_client(config.token.as_deref());
+        let client = build_http_client(config.token()?.as_deref());
 
         Ok(Self {
             endpoint: Url::parse(&config.endpoint)?,

client/src/command/login.rs

@@ -3,7 +3,7 @@ use clap::Parser;
 
 use crate::cache::ServerName;
 use crate::cli::Opts;
-use crate::config::{Config, ServerConfig};
+use crate::config::{Config, ServerConfig, ServerTokenConfig};
 
 /// Log into an Attic server.
 #[derive(Debug, Parser)]
@@ -32,8 +32,10 @@ pub async fn run(opts: Opts) -> Result<()> {
 
         server.endpoint = sub.endpoint.to_owned();
 
-        if sub.token.is_some() {
-            server.token = sub.token.to_owned();
+        if let Some(token) = &sub.token {
+            server.token = Some(ServerTokenConfig::Raw {
+                token: token.clone(),
+            });
         }
     } else {
         eprintln!("✍️ Configuring server \"{}\"", sub.name.as_str());
@@ -42,7 +44,10 @@ pub async fn run(opts: Opts) -> Result<()> {
             sub.name.to_owned(),
             ServerConfig {
                 endpoint: sub.endpoint.to_owned(),
-                token: sub.token.to_owned(),
+                token: sub
+                    .token
+                    .to_owned()
+                    .map(|token| ServerTokenConfig::Raw { token }),
             },
         );
     }

client/src/command/use.rs

@@ -49,7 +49,7 @@ pub async fn run(opts: Opts) -> Result<()> {
     nix_config.add_trusted_public_key(&public_key);
 
     // Modify netrc
-    if let Some(token) = &server.token {
+    if let Some(token) = server.token()? {
         eprintln!("+ Access Token");
 
         let mut nix_netrc = NixNetrc::load().await?;

client/src/config.rs

@@ -5,13 +5,13 @@
 //! experience (e.g., `attic login`).
 
 use std::collections::HashMap;
-use std::fs::{self, OpenOptions, Permissions};
+use std::fs::{self, read_to_string, OpenOptions, Permissions};
 use std::io::Write;
 use std::ops::{Deref, DerefMut};
 use std::os::unix::fs::{OpenOptionsExt, PermissionsExt};
 use std::path::PathBuf;
 
-use anyhow::{anyhow, Result};
+use anyhow::{anyhow, Context, Result};
 use serde::{Deserialize, Serialize};
 use xdg::BaseDirectories;
 
@@ -52,7 +52,38 @@ pub struct ConfigData {
 #[derive(Debug, Clone, Deserialize, Serialize)]
 pub struct ServerConfig {
     pub endpoint: String,
-    pub token: Option<String>,
+    #[serde(flatten)]
+    pub token: Option<ServerTokenConfig>,
+}
+
+impl ServerConfig {
+    pub fn token(&self) -> Result<Option<String>> {
+        self.token.as_ref().map(|token| token.get()).transpose()
+    }
+}
+
+/// Configured server token
+#[derive(Debug, Clone, Deserialize, Serialize)]
+#[serde(untagged)]
+pub enum ServerTokenConfig {
+    Raw {
+        token: String,
+    },
+    File {
+        #[serde(rename = "token-file")]
+        token_file: String,
+    },
+}
+
+impl ServerTokenConfig {
+    /// Get the token either directly from the config or through the token file
+    pub fn get(&self) -> Result<String> {
+        match self {
+            ServerTokenConfig::Raw { token } => Ok(token.clone()),
+            ServerTokenConfig::File { token_file } => Ok(read_to_string(token_file)
+                .with_context(|| format!("Failed to read token from {token_file}"))?),
+        }
+    }
 }
 
 /// Wrapper that automatically saves the config once dropped.