Add rate limiter, rename maxConn into inFlightReq

Co-authored-by: Julien Salleyron <[email protected]>
Co-authored-by: Jean-Baptiste Doumenjou <[email protected]>

Author: 3 people

docs/content/assets/img/middleware/maxconnection.png renamed to docs/content/assets/img/middleware/inflightreq.png

@@ -34,6 +34,10 @@ h3 {
     font-weight: bold !important;
 }
 
+.md-typeset h5 {
+    text-transform: none;
+}
+
 figcaption {
     text-align: center;
     font-size: 0.8em;

docs/content/assets/styles/extra.css

@@ -0,0 +1,247 @@
+# InFlightReq
+
+Limiting the Number of Simultaneous In-Flight Requests
+{: .subtitle }
+
+![InFlightReq](../assets/img/middleware/inflightreq.png)
+
+To proactively prevent services from being overwhelmed with high load, a limit on the number of simultaneous in-flight requests can be applied.
+
+## Configuration Examples
+
+```yaml tab="Docker"
+labels:
+- "traefik.http.middlewares.test-inflightreq.inflightreq.amount=10"
+```
+
+```yaml tab="Kubernetes"
+apiVersion: traefik.containo.us/v1alpha1
+kind: Middleware
+metadata:
+  name: test-inflightreq
+spec:
+  inFlightReq:
+    amount: 10
+```
+
+```json tab="Marathon"
+"labels": {
+  "traefik.http.middlewares.test-inflightreq.inflightreq.amount": "10"
+}
+```
+
+```yaml tab="Rancher"
+# Limiting to 10 simultaneous connections
+labels:
+- "traefik.http.middlewares.test-inflightreq.inflightreq.amount=10"
+```
+
+```toml tab="File (TOML)"
+# Limiting to 10 simultaneous connections
+[http.middlewares]
+  [http.middlewares.test-inflightreq.inFlightReq]
+    amount = 10 
+```
+
+```yaml tab="File (YAML)"
+# Limiting to 10 simultaneous connections
+http:
+  middlewares:
+    test-inflightreq:
+      inFlightReq:
+        amount: 10 
+```
+
+## Configuration Options
+
+### `amount`
+
+The `amount` option defines the maximum amount of allowed simultaneous in-flight request.
+The middleware will return an `HTTP 429 Too Many Requests` if there are already `amount` requests in progress (based on the same `sourceCriterion` strategy).
+
+### `sourceCriterion`
+ 
+SourceCriterion defines what criterion is used to group requests as originating from a common source.
+The precedence order is `ipStrategy`, then `requestHeaderName`, then `requestHost`.
+If none are set, the default is to use the `requestHost`.
+
+#### `sourceCriterion.ipStrategy`
+
+The `ipStrategy` option defines two parameters that sets how Traefik will determine the client IP: `depth`, and `excludedIPs`.
+
+##### `ipStrategy.depth`
+
+The `depth` option tells Traefik to use the `X-Forwarded-For` header and take the IP located at the `depth` position (starting from the right).
+
+- If `depth` is greater than the total number of IPs in `X-Forwarded-For`, then the client IP will be empty.
+- `depth` is ignored if its value is is lesser than or equal to 0.
+    
+!!! note "Example of Depth & X-Forwarded-For"
+
+    If `depth` was equal to 2, and the request `X-Forwarded-For` header was `"10.0.0.1,11.0.0.1,12.0.0.1,13.0.0.1"` then the "real" client IP would be `"10.0.0.1"` (at depth 4) but the IP used as the criterion would be `"12.0.0.1"` (`depth=2`).
+
+    | `X-Forwarded-For`                       | `depth` | clientIP     |
+    |-----------------------------------------|---------|--------------|
+    | `"10.0.0.1,11.0.0.1,12.0.0.1,13.0.0.1"` | `1`     | `"13.0.0.1"` |
+    | `"10.0.0.1,11.0.0.1,12.0.0.1,13.0.0.1"` | `3`     | `"11.0.0.1"` |
+    | `"10.0.0.1,11.0.0.1,12.0.0.1,13.0.0.1"` | `5`     | `""`         |
+
+##### `ipStrategy.excludedIPs`
+
+`excludedIPs` tells Traefik to scan the `X-Forwarded-For` header and pick the first IP not in the list.
+
+!!! important
+    If `depth` is specified, `excludedIPs` is ignored.
+
+!!! note "Example of ExcludedIPs & X-Forwarded-For"
+
+    | `X-Forwarded-For`                       | `excludedIPs`         | clientIP     |
+    |-----------------------------------------|-----------------------|--------------|
+    | `"10.0.0.1,11.0.0.1,12.0.0.1,13.0.0.1"` | `"12.0.0.1,13.0.0.1"` | `"11.0.0.1"` |
+    | `"10.0.0.1,11.0.0.1,12.0.0.1,13.0.0.1"` | `"15.0.0.1,13.0.0.1"` | `"12.0.0.1"` |
+    | `"10.0.0.1,11.0.0.1,12.0.0.1,13.0.0.1"` | `"10.0.0.1,13.0.0.1"` | `"12.0.0.1"` |
+    | `"10.0.0.1,11.0.0.1,12.0.0.1,13.0.0.1"` | `"15.0.0.1,16.0.0.1"` | `"13.0.0.1"` |
+    | `"10.0.0.1,11.0.0.1"`                   | `"10.0.0.1,11.0.0.1"` | `""`         |
+
+```yaml tab="Docker"
+labels:
+- "traefik.http.middlewares.test-inflightreq.inflightreq.sourcecriterion.ipstrategy.excludedips=127.0.0.1/32, 192.168.1.7"
+```
+
+```yaml tab="Kubernetes"
+apiVersion: traefik.containo.us/v1alpha1
+kind: Middleware
+metadata:
+  name: test-inflightreq
+spec:
+  inFlightReq:
+    sourceCriterion:
+      ipStrategy:
+        excludedIPs:
+        - 127.0.0.1/32
+        - 192.168.1.7
+```
+
+```yaml tab="Rancher"
+labels:
+- "traefik.http.middlewares.test-inflightreq.inflightreq.sourcecriterion.ipstrategy.excludedips=127.0.0.1/32, 192.168.1.7"
+```
+
+```json tab="Marathon"
+"labels": {
+  "traefik.http.middlewares.test-inflightreq.inflightreq.sourcecriterion.ipstrategy.excludedips": "127.0.0.1/32, 192.168.1.7"
+}
+```
+
+```toml tab="File (TOML)"
+[http.middlewares]
+  [http.middlewares.test-inflightreq.inflightreq]
+    [http.middlewares.test-inflightreq.inFlightReq.sourceCriterion.ipStrategy]
+      excludedIPs = ["127.0.0.1/32", "192.168.1.7"]
+```
+
+```yaml tab="File (YAML)"
+http:
+  middlewares:
+    test-inflightreq:
+      inFlightReq:
+        sourceCriterion:
+          ipStrategy:
+            excludedIPs:
+            - "127.0.0.1/32"
+            - "192.168.1.7"
+```
+
+#### `sourceCriterion.requestHeaderName`
+
+Requests having the same value for the given header are grouped as coming from the same source.
+
+```yaml tab="Docker"
+labels:
+- "traefik.http.middlewares.test-inflightreq.inflightreq.sourcecriterion.requestheadername=username"
+```
+
+```yaml tab="Kubernetes"
+apiVersion: traefik.containo.us/v1alpha1
+kind: Middleware
+metadata:
+  name: test-inflightreq
+spec:
+  inFlightReq:
+	sourceCriterion:
+      requestHeaderName: username
+```
+
+```yaml tab="Rancher"
+labels:
+- "traefik.http.middlewares.test-inflightreq.inflightreq.sourcecriterion.requestheadername=username"
+```
+
+```json tab="Marathon"
+"labels": {
+  "traefik.http.middlewares.test-inflightreq.inflightreq.sourcecriterion.requestheadername": "username"
+}
+```
+
+```toml tab="File (TOML)"
+[http.middlewares]
+  [http.middlewares.test-inflightreq.inflightreq]
+    [http.middlewares.test-inflightreq.inFlightReq.sourceCriterion]
+      requestHeaderName = "username"
+```
+
+```yaml tab="File (YAML)"
+http:
+  middlewares:
+    test-inflightreq:
+      inFlightReq:
+        sourceCriterion:
+          requestHeaderName: username
+```
+
+#### `sourceCriterion.requestHost`
+
+Whether to consider the request host as the source.
+
+```yaml tab="Docker"
+labels:
+- "traefik.http.middlewares.test-inflightreq.inflightreq.sourcecriterion.requesthost=true"
+```
+
+```yaml tab="Kubernetes"
+apiVersion: traefik.containo.us/v1alpha1
+kind: Middleware
+metadata:
+  name: test-inflightreq
+spec:
+  inFlightReq:
+    sourceCriterion:
+      requestHost: true
+```
+
+```yaml tab="Rancher"
+labels:
+- "traefik.http.middlewares.test-inflightreq.inflightreq.sourcecriterion.requesthost=true"
+```
+
+```json tab="Marathon"
+"labels": {
+  "traefik.http.middlewares.test-inflightreq.inflightreq.sourcecriterion.requesthost": "true"
+}
+```
+
+```toml tab="File (TOML)"
+[http.middlewares]
+  [http.middlewares.test-inflightreq.inflightreq]
+    [http.middlewares.test-inflightreq.inFlightReq.sourceCriterion]
+      requestHost = true
+```
+
+```yaml tab="File (YAML)"
+http:
+  middlewares:
+    test-inflightreq:
+      inFlightReq:
+        sourceCriterion:
+          requestHost: true
+```

docs/content/middlewares/inflightreq.md

@@ -208,7 +208,7 @@ and therefore this specification would be ignored even if present.
 | [ForwardAuth](forwardauth.md)             | Authentication delegation                         | Security, Authentication    |
 | [Headers](headers.md)                     | Add / Update headers                              | Security                    |
 | [IPWhiteList](ipwhitelist.md)             | Limit the allowed client IPs                      | Security, Request lifecycle |
-| [MaxConnection](maxconnection.md)         | Limit the number of simultaneous connections      | Security, Request lifecycle |
+| [InFlightReq](inflightreq.md)             | Limit the number of simultaneous connections      | Security, Request lifecycle |
 | [PassTLSClientCert](passtlsclientcert.md) | Adding Client Certificates in a Header            | Security                    |
 | [RateLimit](ratelimit.md)                 | Limit the call frequency                          | Security, Request lifecycle |
 | [RedirectScheme](redirectscheme.md)       | Redirect easily the client elsewhere              | Request lifecycle           |