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Merge pull request #47799 from fastly/jkarneges/buildrs-defaults
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build.rs: allow configuring via env vars and falling back to defaults
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@jkarneges
jkarneges authored Nov 27, 2023
2 parents b0d90f7 + 6bb4eb6 commit 5942abe
Showing 1 changed file with 110 additions and 37 deletions.
147 changes: 110 additions & 37 deletions build.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -2,7 +2,7 @@ use std::collections::HashMap;
use std::env;
use std::error::Error;
use std::fs;
use std::io::{BufRead, BufReader, Write};
use std::io::{self, BufRead, BufReader, Write};
use std::path::{Path, PathBuf};
use std::process::Command;
use std::thread;
Expand Down Expand Up @@ -51,6 +51,64 @@ fn check_version(
Ok(())
}

fn prefixed_vars(prefix: &str) -> HashMap<String, String> {
let mut out = HashMap::new();

out.insert("BINDIR".into(), format!("{}/bin", prefix));
out.insert("CONFIGDIR".into(), format!("{}/etc", prefix));
out.insert("LIBDIR".into(), format!("{}/lib", prefix));
out.insert("LOGDIR".into(), "/var/log".into());
out.insert("RUNDIR".into(), "/var/run".into());

out
}

fn read_conf_pri() -> Result<HashMap<String, String>, Box<dyn Error>> {
let mut conf = HashMap::new();

let f = fs::File::open("conf.pri")?;

let reader = BufReader::new(f);

const CONF_VARS: &[&str] = &["BINDIR", "CONFIGDIR", "LIBDIR", "LOGDIR", "RUNDIR"];

for line in reader.lines() {
let line = line?;

for name in CONF_VARS {
if line.starts_with(name) {
let pos = match line.find('=') {
Some(pos) => pos,
None => return Err(format!("no '=' character following var {}", name).into()),
};

conf.insert(name.to_string(), line[(pos + 1)..].trim().to_string());
break;
}
}
}

const SUFFIXED: &[&str] = &["CONFIGDIR", "LIBDIR", "LOGDIR", "RUNDIR"];

for (k, v) in conf.iter_mut() {
if SUFFIXED.contains(&k.as_str()) {
match v.strip_suffix("/pushpin") {
Some(s) => *v = s.to_string(),
None => return Err(format!("var {} missing /pushpin suffix", k).into()),
}
}
}

Ok(conf)
}

fn env_or_default(name: &str, defaults: &HashMap<String, String>) -> String {
match env::var(name) {
Ok(s) => s,
Err(_) => defaults.get(name).unwrap().to_string(),
}
}

fn write_cpp_conf_pri(path: &Path) -> Result<(), Box<dyn Error>> {
let mut f = fs::File::create(path)?;

Expand All @@ -71,10 +129,10 @@ fn write_postbuild_conf_pri(
let mut f = fs::File::create(path)?;

writeln!(&mut f, "BINDIR = {}", bin_dir)?;
writeln!(&mut f, "LIBDIR = {}", lib_dir)?;
writeln!(&mut f, "CONFIGDIR = {}", config_dir)?;
writeln!(&mut f, "RUNDIR = {}", run_dir)?;
writeln!(&mut f, "LOGDIR = {}", log_dir)?;
writeln!(&mut f, "LIBDIR = {}/pushpin", lib_dir)?;
writeln!(&mut f, "CONFIGDIR = {}/pushpin", config_dir)?;
writeln!(&mut f, "RUNDIR = {}/pushpin", run_dir)?;
writeln!(&mut f, "LOGDIR = {}/pushpin", log_dir)?;

Ok(())
}
Expand Down Expand Up @@ -119,36 +177,45 @@ fn main() -> Result<(), Box<dyn Error>> {
})?
};

let conf = {
let mut conf = HashMap::new();

let f = fs::File::open("conf.pri")?;
let reader = BufReader::new(f);

const CONF_VARS: &[&str] = &["BINDIR", "CONFIGDIR", "LIBDIR", "LOGDIR", "RUNDIR"];

for line in reader.lines() {
let line = line?;

for name in CONF_VARS {
if line.starts_with(name) {
let pos = line
.find('=')
.unwrap_or_else(|| panic!("no '=' character following var {}", name));
conf.insert(name.to_string(), line[(pos + 1)..].trim().to_string());
break;
let default_vars = {
let prefix = match env::var("PREFIX") {
Ok(s) => Some(s),
Err(env::VarError::NotPresent) => None,
Err(env::VarError::NotUnicode(_)) => return Err("PREFIX not unicode".into()),
};

let vars = if let Some(prefix) = prefix {
Some(prefixed_vars(&prefix))
} else {
match read_conf_pri() {
Ok(vars) => Some(vars),
Err(e) => {
let e: Option<Box<dyn Error>> = match e.downcast::<io::Error>() {
Ok(e) if e.kind() == io::ErrorKind::NotFound => None,
Ok(e) => Some(e),
Err(e) => Some(e),
};

if let Some(e) = e {
return Err(format!("failed to read conf.pri: {}", e).into());
}

None
}
}
}
};

conf
match vars {
Some(vars) => vars,
None => prefixed_vars("/usr/local"),
}
};

let bin_dir = conf.get("BINDIR").unwrap();
let config_dir = conf.get("CONFIGDIR").unwrap();
let lib_dir = conf.get("LIBDIR").unwrap();
let log_dir = conf.get("LOGDIR").unwrap();
let run_dir = conf.get("RUNDIR").unwrap();
let bin_dir = env_or_default("BINDIR", &default_vars);
let config_dir = env_or_default("CONFIGDIR", &default_vars);
let lib_dir = env_or_default("LIBDIR", &default_vars);
let log_dir = env_or_default("LOGDIR", &default_vars);
let run_dir = env_or_default("RUNDIR", &default_vars);

let root_dir = PathBuf::from(env::var("CARGO_MANIFEST_DIR")?);
let cpp_src_dir = root_dir.join(Path::new("src/cpp"));
Expand All @@ -162,11 +229,11 @@ fn main() -> Result<(), Box<dyn Error>> {

write_postbuild_conf_pri(
&Path::new("target").join(Path::new("postbuild_conf.pri")),
bin_dir,
lib_dir,
config_dir,
run_dir,
log_dir,
&bin_dir,
&lib_dir,
&config_dir,
&run_dir,
&log_dir,
)?;

if !cpp_src_dir.join("Makefile").try_exists()? {
Expand All @@ -186,8 +253,8 @@ fn main() -> Result<(), Box<dyn Error>> {
.success());

println!("cargo:rustc-env=APP_VERSION={}", get_version());
println!("cargo:rustc-env=CONFIG_DIR={}", config_dir);
println!("cargo:rustc-env=LIB_DIR={}", lib_dir);
println!("cargo:rustc-env=CONFIG_DIR={}/pushpin", config_dir);
println!("cargo:rustc-env=LIB_DIR={}/pushpin", lib_dir);

println!("cargo:rustc-link-search={}", cpp_lib_dir.display());

Expand All @@ -200,6 +267,12 @@ fn main() -> Result<(), Box<dyn Error>> {
#[cfg(not(target_os = "macos"))]
println!("cargo:rustc-link-search={}", qt_install_libs.display());

println!("cargo:rerun-if-env-changed=PREFIX");
println!("cargo:rerun-if-env-changed=BINDIR");
println!("cargo:rerun-if-env-changed=CONFIGDIR");
println!("cargo:rerun-if-env-changed=LIBDIR");
println!("cargo:rerun-if-env-changed=LOGDIR");
println!("cargo:rerun-if-env-changed=RUNDIR");
println!("cargo:rerun-if-changed=conf.pri");
println!("cargo:rerun-if-changed=src");

Expand Down

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