# alog
[](https://crates.io/crates/alog)
[](https://github.com/thyrc/alog/actions?query=workflow%3ARust)
[](https://docs.rs/alog)
[](https://github.com/thyrc/alog/blob/master/LICENSE)
`alog` is a simple log file anonymizer.
## About
In fact by default `alog` just replaces the first *word* on every line of any input stream
with a customizable string.
With version 0.6
* you can (at a substantial cost of CPU cycles) replace the `$remote_user` with '-' as well and
* by default any leading Spaces or Tabs will be removed from every line before replacing any `$remote_addr`.
So "log file anonymizer" might be a bit of an overstatement, but `alog` can be used to (very
efficiently) replace the `$remote_addr` part in many access log formats, e.g. Nginx' default
combined log format:
```text
log_format combined '$remote_addr - $remote_user [$time_local] '
'"$request" $status $body_bytes_sent '
'"$http_referer" "$http_user_agent"';
```
By default any parseable `$remote_addr` is replaced by it's *localhost* representation,
* any valid IPv4 address is replaced by *127.0.0.1*,
* any valid IPv6 address is replaced by *::1* and
* any String (what might be a domain name) with *localhost*.
Lines without a `$remote_addr` part will remain unchanged (but can be skipped).
## Building alog
With version 0.3 `[features]` where added, so that the library crate won't pull unneeded
dependencies anymore.
### Commandline Tool
To build the `alog` commandline tool you now have to expicitly add `--features`.
```shell
cargo build --features alog-cli
```
or
```shell
cargo build --all-features
```
## Usage
### Commandline tool
Run cli-tool with `--help`.
```shell
./target/release/alog --help
```
### Library
Calling `run()`
```rust
extern crate alog;
fn main() {
let mut io_conf = alog::IOConfig::default();
let mut conf = alog::Config::default();
io_conf.push_input("/tmp/test.log");
conf.set_ipv4_value("0.0.0.0");
alog::run(&conf, &io_conf);
}
```
or `run_raw()`
```rust
extern crate alog;
use std::io::Cursor;
fn main() {
let mut buffer = vec![];
alog::run_raw(
&alog::Config {
ipv4: "XXX",
..Default::default()
},
Cursor::new(b"8.8.8.8 test line"),
&mut buffer,
);
assert_eq!(buffer, b"XXX test line");
}
```
## About `Config::authuser`
With version 0.6 `alog` can be used to replace the `$remote_user` field with '-', but this
feature comes with a couple of peculiarities.
This feature should work fine with standard Common / Combined Log formatted files, but...
* There will be a significant hit on performance (synthetic benchmarking suggests ~625MB/s
instead of ~1100MB/s on my machine, but still better than Perl's ~115MB/s ;)
* Used with `Config::trim` set to `false` and malformatted files the performance hit will be
even worse and removal of the `$remote_user` field will fail altogether if no `$time_local`
field is found.
* The `$time_local` field is expected to start with '[' followed by a decimal number. E.g.:
"[10/Oct/2000:13:55:36 -0700]"
* There is an optimization in place to reduce the performance hit with real-life log files,
but this leads to `$remote_user` fields *starting* with "- [" _not_ being replaced! So in
`"8.8.8.8 - - [frank] [10/Oct/2000:13:55:36 -0700] GET /apache_pb.gif HTTP/1.0 200 2326"`
"frank" will still be "frank". This optimization can be disabled.
## Project status
`alog` started as a replacement for a <10 line Perl script running on an old backup host.
So nothing shiny.. but it helped me learning some Rust (and crates.io) basics.
With version 0.6 `alog` is feature complete. It doesn't do much, but it does it quite well.
At some point I might re-use this crate and try harder to actually anonymize data. But for
now, this is it.
I will still fix bugs when (and if) I find them, so `alog` is now passively-maintained.