61 lines
2.4 KiB
Rust
61 lines
2.4 KiB
Rust
use std::{
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default::default,
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env,
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ffi::{OsStr, OsString},
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fs::File,
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io::Read,
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};
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// from https://doc.rust-lang.org/std/ffi/struct.OsString.html
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fn concat_os_strings(a: &OsStr, b: &OsStr) -> OsString {
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let mut ret = OsString::with_capacity(a.len() + b.len()); // This will allocate
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ret.push(a); // This will not allocate further
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ret.push(b); // This will not allocate further
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ret
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}
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/// Check for an environment variable named for the given key with _FILE
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/// appended to the end. If that exists, return the contents of the file, or
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/// panic if it doesn't exist. If the `"${key}_FILE"` environment variable is
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/// not set, return the value of the environment variable set by the given key,
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/// or `None` if it's not set.
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///
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/// Panics:
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/// - if the given file variable doesn't exist
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/// - if there's an error reading the specified file
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/// - if the environment variable string contains invalid unicode.
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fn get_env_var_or_file<A: AsRef<OsStr>>(key: A) -> Option<String> {
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let key = key.as_ref();
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let file_key = concat_os_strings(key, "_FILE".as_ref());
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if let Some(path) = env::var_os(file_key) {
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// open the file and read it
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let mut file = File::open(&path).unwrap_or_else(|_| panic!("no such file at {path:?}"));
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let mut val: String = default();
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file.read_to_string(&mut val)
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.unwrap_or_else(|_| panic!("reading file at {path:?}"));
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Some(val)
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} else {
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env::var_os(key).map(|val| {
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val.to_str()
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.expect(&format!("value for ${key:?} contains invalid unicode"))
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.to_string()
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})
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}
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}
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/// Connect to the database using environment variables for configuration.
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/// Panics on any failure.
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pub(crate) fn connection_url() -> String {
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let user = get_env_var_or_file("POSTGRES_USER").expect("$POSTGRES_USER");
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let password = get_env_var_or_file("POSTGRES_PASSWORD").expect("$POSTGRES_PASSWORD");
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let db = get_env_var_or_file("POSTGRES_DB").expect("$POSTGRES_DB");
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let host = get_env_var_or_file("POSTGRES_HOST").unwrap_or_else(|| "localhost".into());
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let port = get_env_var_or_file("POSTGRES_PORT")
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.map(|port| {
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port.parse::<u16>()
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.expect("$POSTGRES_PORT is not a valid port number")
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})
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.unwrap_or(5432_u16);
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format!("postgres://{user}:{password}@{host}:{port}/{db}")
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}
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