Allow the configuration of some default values at compile time using environment variables

CHANGELOG.md

@@ -13,6 +13,12 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
 and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
 
 
+## [Unreleased]
+
+### Added
+- Allow the configuration of some default values at compile time using environment variables.
+
+
 ## [0.16.0] - 2020-11-11
 
 ### Added

README.md

@@ -110,6 +110,14 @@ For example, you can build statically linked binaries using the `openssl_vendore
 make FEATURES="openssl_vendored" TARGET="x86_64-unknown-linux-musl"
 ```
 
+The following environment variables can be used to change default values at compile time:
+
+- `ACMED_DEFAULT_ACCOUNTS_DIR`: directory where account files are stored (default to `/etc/acmed/accounts`)
+- `ACMED_DEFAULT_CERT_DIR`: directory where certificates and private keys are stored (default to `/etc/acmed/certs`)
+- `ACMED_DEFAULT_CERT_FORMAT`: format for certificates and private keys files names (default to `{{name}}_{{key_type}}.{{file_type}}.{{ext}}`)
+- `ACMED_DEFAULT_CONFIG_FILE`: main configuration file (default to `/etc/acmed/acmed.toml`)
+- `ACMED_DEFAULT_PID_FILE`: main process PID file (default to `/var/run/acmed.pid`)
+
 ### Packaging
 
 Most of the time, when packaging, you want to install the program in a dedicated directory. This is possible using the `DESTDIR` variable.

acmed/build.rs

@@ -7,6 +7,14 @@ use std::fs::File;
 use std::io::prelude::*;
 use std::path::PathBuf;
 
+macro_rules! set_env_var_if_absent {
+    ($name: expr, $default_value: expr) => {{
+        if let Err(_) = env::var($name) {
+            set_rustc_env_var!($name, $default_value);
+        }
+    }};
+}
+
 macro_rules! set_rustc_env_var {
     ($name: expr, $value: expr) => {{
         println!("cargo:rustc-env={}={}", $name, $value);
@@ -73,7 +81,19 @@ fn set_target() {
     };
 }
 
+fn set_default_values() {
+    set_env_var_if_absent!("ACMED_DEFAULT_ACCOUNTS_DIR", "/etc/acmed/accounts");
+    set_env_var_if_absent!("ACMED_DEFAULT_CERT_DIR", "/etc/acmed/certs");
+    set_env_var_if_absent!(
+        "ACMED_DEFAULT_CERT_FORMAT",
+        "{{name}}_{{key_type}}.{{file_type}}.{{ext}}"
+    );
+    set_env_var_if_absent!("ACMED_DEFAULT_CONFIG_FILE", "/etc/acmed/acmed.toml");
+    set_env_var_if_absent!("ACMED_DEFAULT_PID_FILE", "/var/run/acmed.pid");
+}
+
 fn main() {
     set_target();
     set_lock();
+    set_default_values();
 }

acmed/src/main.rs

@@ -23,11 +23,11 @@ mod storage;
 
 pub const APP_NAME: &str = "ACMEd";
 pub const APP_VERSION: &str = env!("CARGO_PKG_VERSION");
-pub const DEFAULT_PID_FILE: &str = "/var/run/acmed.pid";
-pub const DEFAULT_CONFIG_FILE: &str = "/etc/acmed/acmed.toml";
-pub const DEFAULT_ACCOUNTS_DIR: &str = "/etc/acmed/accounts";
-pub const DEFAULT_CERT_DIR: &str = "/etc/acmed/certs";
-pub const DEFAULT_CERT_FORMAT: &str = "{{name}}_{{key_type}}.{{file_type}}.{{ext}}";
+pub const DEFAULT_ACCOUNTS_DIR: &str = env!("ACMED_DEFAULT_ACCOUNTS_DIR");
+pub const DEFAULT_CERT_DIR: &str = env!("ACMED_DEFAULT_CERT_DIR");
+pub const DEFAULT_CERT_FORMAT: &str = env!("ACMED_DEFAULT_CERT_FORMAT");
+pub const DEFAULT_CONFIG_FILE: &str = env!("ACMED_DEFAULT_CONFIG_FILE");
+pub const DEFAULT_PID_FILE: &str = env!("ACMED_DEFAULT_PID_FILE");
 pub const DEFAULT_SLEEP_TIME: u64 = 3600;
 pub const DEFAULT_POOL_TIME: u64 = 5000;
 pub const DEFAULT_CSR_DIGEST: HashFunction = HashFunction::Sha256;