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Docs #127

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64 changes: 9 additions & 55 deletions README.md
Original file line number Diff line number Diff line change
Expand Up @@ -3,17 +3,16 @@
[![Limitador GH Workflow](https://github.com/Kuadrant/limitador/actions/workflows/rust.yml/badge.svg)](https://github.com/Kuadrant/limitador/actions/workflows/rust.yml)
[![docs.rs](https://docs.rs/limitador/badge.svg)](https://docs.rs/limitador)
[![Crates.io](https://img.shields.io/crates/v/limitador)](https://crates.io/crates/limitador)
[![Docker Repository on Quay](https://quay.io/repository/3scale/limitador/status
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this badge only makes sense if the image is being build using quay.io building system. Currently it is being build using GH actions, so this badge should point to GH workflows status badge

"Docker Repository on Quay")](https://quay.io/repository/3scale/limitador)
[![Docker Repository on Quay](https://quay.io/repository/kuadrant/limitador/status
"Docker Repository on Quay")](https://quay.io/repository/kuadrant/limitador)

Limitador is a generic rate-limiter written in Rust. It can be used as a
library, or as a service. The service exposes HTTP endpoints to apply and manage
library, or as a service. The service exposes HTTP endpoints to apply and observe
limits. Limitador can be used with Envoy because it also exposes a grpc service, on a different
port, that implements the Envoy Rate Limit protocol (v3).

- [**Getting started**](#getting-started)
- [**How it works**](/doc/how-it-works.md)
- [**Limits storage**](#limits-storage)
- [**Development**](#development)
- [**Testing Environment**](limitador-server/docs/sandbox.md)
- [**Kubernetes**](limitador-server/kubernetes/)
Expand All @@ -31,70 +30,25 @@ Limitador is under active development, and its API has not been stabilized yet.
Add this to your `Cargo.toml`:
```toml
[dependencies]
limitador = { version = "0.2.0" }
limitador = { version = "0.3.0" }
```

To use Limitador in a project that compiles to WASM, there are some features
that need to be disabled. Add this to your `Cargo.toml` instead:
```toml
[dependencies]
limitador = { version = "0.2.0", default-features = false }
```
For more information, see the [`README` of the crate](limitador/README.md)

### Server

Run with Docker (replace `latest` with the version you want):
```bash
docker run --rm --net=host -it quay.io/3scale/limitador:latest
docker run --rm --net=host -it quay.io/kuadrant/limitador:v1.0.0
```

Run locally:
```bash
cargo run --release --bin limitador-server
```

To use Redis, specify the URL with `REDIS_URL`:
```bash
REDIS_URL=redis://127.0.0.1:6379 cargo run --release --bin limitador-server
```

By default, Limitador starts the HTTP server in `localhost:8080` and the grpc
service that implements the Envoy Rate Limit protocol in `localhost:8081`. That
can be configured with these ENVs: `ENVOY_RLS_HOST`, `ENVOY_RLS_PORT`,
`HTTP_API_HOST`, and `HTTP_API_PORT`.

The OpenAPI spec of the HTTP service is
[here](limitador-server/docs/http_server_spec.json).

Limitador can be started with a YAML file that has some limits predefined. Keep
in mind that they can be modified using the HTTP API. There's an [example
file](limitador-server/examples/limits.yaml) that allows 10 requests per minute
and per user_id when the HTTP method is "GET" and 5 when it is a "POST". You can
run it with Docker (replace `latest` with the version you want):
```bash
docker run -e LIMITS_FILE=/home/limitador/my_limits.yaml --rm --net=host -it -v $(pwd)/limitador-server/examples/limits.yaml:/home/limitador/my_limits.yaml:ro quay.io/3scale/limitador:latest
```

You can also use the YAML file when running locally:
```bash
LIMITS_FILE=./limitador-server/examples/limits.yaml cargo run --release --bin limitador-server
cargo run --release --bin limitador-server -- --help
```

If you want to use Limitador with Envoy, there's a minimal Envoy config for
testing purposes [here](limitador-server/examples/envoy.yaml). The config
forwards the "userid" header and the request method to Limitador. It assumes
that there's an upstream API deployed on port 1323. You can use
[echo](https://github.com/labstack/echo), for example.

Limitador has several options that can be configured via ENV. This
[doc](limitador-server/docs/configuration.md) specifies them.

## Limits storage

Limitador can store its limits and counters in-memory or in Redis. In-memory is
faster, but the limits are applied per instance. When using Redis, multiple
instances of Limitador can share the same limits, but it's slower.

Refer to the help message on how to start up the server. More information are available
in the [server's `README.md`](limitador-server/README.md)

## Development

Expand Down
8 changes: 4 additions & 4 deletions doc/how-it-works.md
Original file line number Diff line number Diff line change
Expand Up @@ -34,11 +34,11 @@ The counter's condition will match. Then, the counter will be increased and the
If the limit is exceeded, the request will be rejected with `429 Too Many Requests`,
otherwise accepted.

Note that the counter is being activated eventhough it does not match *all* the entries of the
Note that the counter is being activated even though it does not match *all* the entries of the
descriptor. The same rule applies for the *variables* field.

Currently *condition* implementation only allows *equal* operator.
More operators can be implemented if there are use cases.
Currently, the implementation of *condition* only allow for *equal* (`==`) and *not equal* (`!=`) operators.
More operators will be implemented based off the use cases for them.

The *variables* field is a list of keys.
The matching rule is defined just as the existence of the list of descriptor entries with the
Expand Down Expand Up @@ -71,7 +71,7 @@ Reason: conditions key does not exist
```yaml
conditions:
- "KEY_A == 'VALUE_A'"
- "OTHER_KEY = 'WRONG_VALUE'"
- "OTHER_KEY == 'WRONG_VALUE'"
max_value: 1
seconds: 60
variables: []
Expand Down
44 changes: 44 additions & 0 deletions doc/migrations/conditions.md
Original file line number Diff line number Diff line change
@@ -0,0 +1,44 @@
# New condition syntax

With `limitador-server` version `1.0.0` (and the `limitador` crate version `0.3.0`), the syntax for `condition`s within
`limit` definitions has changed.

## Changes

### The new syntax

The new syntax formalizes what part of an expression is the identifier and which is the value to test against.
Identifiers are simple string value, while string literals are to be demarcated by single quotes (`'`) or double quotes
(`"`) so that `foo == " bar"` now makes it explicit that the value is to be prefixed with a space character.

A few remarks:
- Only `string` values are supported, as that's what they really are
- There is no escape character sequence supported in string literals
- A new operator has been added, `!=`
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### The issue with the deprecated syntax

The previous syntax wouldn't differentiate between values and the identifier, so that `foo == bar` was valid. In this
case `foo` was the identifier of the variable, while `bar` was the value to evaluate it against. Whitespaces before and
after the operator `==` would be equally important. SO that `foo == bar` would test for a `foo ` variable being equal
to ` bar` where the trailing whitespace after the identifier, and the one prefixing the value, would have been
evaluated.

## Server binary users

The server still allows for the deprecated syntax, but warns about its usage. You can easily migrate your limits file,
using the following command:

```commandline
limitador-server --validate old_limits.yaml > updated_limits.yaml
```

Which should output `Deprecated syntax for conditions corrected!` to `stderr` while `stdout` would be the limits using
the new syntax. It is recommended you manually verify the resulting `LIMITS_FILE`.


## Crate users

A feature `lenient_conditions` has been added, which lets you use the syntax used in previous version of the crate.
The function `limitador::limit::check_deprecated_syntax_usages_and_reset()` lets you verify if the deprecated syntax
has been used as `limit::Limit`s are created with their condition strings using the deprecated syntax.
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