use crate::log_settings::LogSettings;
use lazy_static::lazy_static;
use mlua::{Error as LuaError, Lua};
use regex::Regex;
use serde_json::{Map, Value};
use std::fmt::Write as _;
lazy_static! {
static ref LUA_IDENTIFIER_CLEANUP: Regex = Regex::new(r"[^A-Za-z_]").unwrap();
static ref LUA_STRING_ESCAPE: Regex = Regex::new(r"([\n])").unwrap();
}
pub fn show_log_entry(log_entry: &Map<String, Value>, filter_expr: &str, implicit_return: bool, log_settings: &LogSettings) -> Result<bool, LuaError> {
let lua = Lua::new();
let script = object_to_record(log_entry, false);
if log_settings.print_lua {
println!("{script}");
}
lua.load(&script).exec()?;
if implicit_return {
lua.load(format!("return {filter_expr};")).eval::<bool>()
} else {
lua.load(filter_expr).eval::<bool>()
}
}
fn object_to_record(object: &Map<String, Value>, nested: bool) -> String {
let lines: Vec<String> = object
.iter()
.map(|(key, value)| {
let mut script = String::new();
let key_name = LUA_IDENTIFIER_CLEANUP.replace_all(key, "_");
write!(script, "{key_name} = ").expect("Should be able to write to string");
match value {
Value::String(string_value) => write!(script, "\"{}\"", escape_lua_string(string_value)).expect("Should be able to write to string"),
Value::Bool(bool_value) => script.push_str(&bool_value.to_string()),
Value::Number(number_value) => script.push_str(&number_value.to_string()),
Value::Object(nested_object) => {
let object_string = object_to_record(nested_object, true);
write!(script, "{{{object_string}}}").expect("Should be able to write to string");
}
Value::Array(array_values) => {
let mut values = vec![];
for array_value in array_values.iter() {
let lua_array_value = match array_value {
Value::String(string_value) => format!("\"{}\"", escape_lua_string(string_value)),
Value::Bool(bool_value) => bool_value.to_string(),
Value::Number(number_value) => number_value.to_string(),
_ => "\"unsupported\"".to_string(),
};
values.push(lua_array_value);
}
write!(script, "{{{}}}", values.join(",")).expect("Should be able to write to string");
}
_ => write!(script, "\"unsupported\"").expect("Should be able to write to string"),
}
script
})
.collect();
lines.join(if nested { "," } else { "\n" })
}
fn escape_lua_string(src: &str) -> String {
let mut escaped = String::with_capacity(src.len());
for c in src.chars() {
match c {
'\n' => escaped += "\\n",
'\r' => escaped += "\\r",
'\t' => escaped += "\\t",
'"' => escaped += "\\\"",
'\'' => escaped += "\\'",
'\\' => escaped += "\\\\",
c => write!(escaped, "{c}").expect("Should be able to write to string"),
}
}
escaped
}
#[cfg(test)]
mod tests {
use super::*;
fn test_log_entry() -> Map<String, Value> {
let mut map = Map::new();
map.insert("message".to_string(), Value::String("something happened".to_string()));
map.insert("time".to_string(), Value::String("2017-07-06T15:21:16".to_string()));
map.insert("process".to_string(), Value::String("rust".to_string()));
map.insert("fu".to_string(), Value::String("bower".to_string()));
map.insert("level".to_string(), Value::String("info".to_string()));
let mut nested = Map::new();
nested.insert("log.level".to_string(), Value::String("debug".to_string()));
map.insert("nested".to_string(), Value::Object(nested));
let mut nested_with_array = Map::new();
nested_with_array.insert(
"array".to_string(),
Value::Array(vec![
Value::String("a".to_string()),
Value::String("b".to_string()),
Value::String("c".to_string()),
]),
);
map.insert("nested_with_array".to_string(), Value::Object(nested_with_array));
map
}
#[test]
fn allow_all() {
let log_entry: Map<String, Value> = test_log_entry();
assert!(show_log_entry(&log_entry, "true", true, &LogSettings::new_default_settings()).unwrap());
}
#[test]
fn deny_all() {
let log_entry: Map<String, Value> = test_log_entry();
assert!(!show_log_entry(&log_entry, "false", true, &LogSettings::new_default_settings()).unwrap());
}
#[test]
fn filter_process() {
let log_entry: Map<String, Value> = test_log_entry();
assert!(show_log_entry(&log_entry, r#"process == "rust""#, true, &LogSettings::new_default_settings()).unwrap());
assert!(!show_log_entry(&log_entry, r#"process == "meep""#, true, &LogSettings::new_default_settings()).unwrap());
}
#[test]
fn filter_logical_operators() {
let log_entry: Map<String, Value> = test_log_entry();
assert!(show_log_entry(&log_entry, r#"process == "rust" and fu == "bower""#, true, &LogSettings::new_default_settings()).unwrap());
assert!(show_log_entry(&log_entry, r#"process == "rust" or fu == "bauer""#, true, &LogSettings::new_default_settings()).unwrap());
}
#[test]
fn filter_contains() {
let log_entry: Map<String, Value> = test_log_entry();
assert!(
show_log_entry(
&log_entry,
r#"string.find(message, "something") ~= nil"#,
true,
&LogSettings::new_default_settings()
)
.unwrap()
);
assert!(!show_log_entry(&log_entry, r#"string.find(message, "bla") ~= nil"#, true, &LogSettings::new_default_settings()).unwrap());
}
#[test]
fn filter_regex() {
let log_entry: Map<String, Value> = test_log_entry();
assert!(show_log_entry(&log_entry, r#"string.find(fu, "bow.*") ~= nil"#, true, &LogSettings::new_default_settings()).unwrap());
assert!(!show_log_entry(&log_entry, r#"string.find(fu, "bow.*sd") ~= nil"#, true, &LogSettings::new_default_settings()).unwrap());
}
#[test]
fn unknown_variable() {
let log_entry: Map<String, Value> = test_log_entry();
assert!(
!show_log_entry(
&log_entry,
r#"sdkfjsdfjsf ~= nil and string.find(sdkfjsdfjsf, "bow.*") ~= nil"#,
true,
&LogSettings::new_default_settings()
)
.unwrap()
);
}
#[test]
fn no_implicit_return() {
let log_entry: Map<String, Value> = test_log_entry();
assert!(
show_log_entry(
&log_entry,
r#"if 3 > 2 then return true else return false end"#,
false,
&LogSettings::new_default_settings()
)
.unwrap()
);
assert!(
!show_log_entry(
&log_entry,
r#"if 1 > 2 then return true else return false end"#,
false,
&LogSettings::new_default_settings()
)
.unwrap()
);
}
#[test]
fn neted() {
let log_entry: Map<String, Value> = test_log_entry();
assert!(show_log_entry(&log_entry, r#"nested.log_level == "debug""#, true, &LogSettings::new_default_settings()).unwrap());
}
#[test]
fn nested_with_array() {
let log_entry: Map<String, Value> = test_log_entry();
assert!(show_log_entry(&log_entry, r#"nested_with_array.array[2] == "b""#, true, &LogSettings::new_default_settings()).unwrap());
}
}