299 lines
8.4 KiB
Markdown
299 lines
8.4 KiB
Markdown
---
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title: "Traefik InFlightReq Documentation"
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description: "Traefik Proxy's HTTP middleware lets you limit the number of simultaneous in-flight requests. Read the technical documentation."
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---
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# InFlightReq
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Limiting the Number of Simultaneous In-Flight Requests
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{: .subtitle }
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![InFlightReq](../../assets/img/middleware/inflightreq.png)
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To proactively prevent services from being overwhelmed with high load, the number of allowed simultaneous in-flight requests can be limited.
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## Configuration Examples
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```yaml tab="Docker"
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labels:
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- "traefik.http.middlewares.test-inflightreq.inflightreq.amount=10"
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```
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```yaml tab="Kubernetes"
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apiVersion: traefik.containo.us/v1alpha1
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kind: Middleware
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metadata:
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name: test-inflightreq
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spec:
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inFlightReq:
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amount: 10
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```
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```yaml tab="Consul Catalog"
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# Limiting to 10 simultaneous connections
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- "traefik.http.middlewares.test-inflightreq.inflightreq.amount=10"
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```
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```yaml tab="File (YAML)"
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# Limiting to 10 simultaneous connections
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http:
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middlewares:
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test-inflightreq:
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inFlightReq:
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amount: 10
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```
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```toml tab="File (TOML)"
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# Limiting to 10 simultaneous connections
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[http.middlewares]
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[http.middlewares.test-inflightreq.inFlightReq]
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amount = 10
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```
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## Configuration Options
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### `amount`
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The `amount` option defines the maximum amount of allowed simultaneous in-flight request.
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The middleware responds with `HTTP 429 Too Many Requests` if there are already `amount` requests in progress (based on the same `sourceCriterion` strategy).
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```yaml tab="Docker"
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labels:
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- "traefik.http.middlewares.test-inflightreq.inflightreq.amount=10"
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```
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```yaml tab="Kubernetes"
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apiVersion: traefik.containo.us/v1alpha1
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kind: Middleware
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metadata:
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name: test-inflightreq
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spec:
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inFlightReq:
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amount: 10
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```
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```yaml tab="Consul Catalog"
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# Limiting to 10 simultaneous connections
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- "traefik.http.middlewares.test-inflightreq.inflightreq.amount=10"
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```
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```yaml tab="File (YAML)"
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# Limiting to 10 simultaneous connections
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http:
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middlewares:
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test-inflightreq:
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inFlightReq:
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amount: 10
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```
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```toml tab="File (TOML)"
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# Limiting to 10 simultaneous connections
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[http.middlewares]
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[http.middlewares.test-inflightreq.inFlightReq]
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amount = 10
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```
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### `sourceCriterion`
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The `sourceCriterion` option defines what criterion is used to group requests as originating from a common source.
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If several strategies are defined at the same time, an error will be raised.
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If none are set, the default is to use the `requestHost`.
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#### `sourceCriterion.ipStrategy`
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The `ipStrategy` option defines two parameters that configures how Traefik determines the client IP: `depth`, and `excludedIPs`.
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!!! important "As a middleware, InFlightReq happens before the actual proxying to the backend takes place. In addition, the previous network hop only gets appended to `X-Forwarded-For` during the last stages of proxying, i.e. after it has already passed through the middleware. Therefore, during InFlightReq, as the previous network hop is not yet present in `X-Forwarded-For`, it cannot be used and/or relied upon."
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##### `ipStrategy.depth`
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The `depth` option tells Traefik to use the `X-Forwarded-For` header and select the IP located at the `depth` position (starting from the right).
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- If `depth` is greater than the total number of IPs in `X-Forwarded-For`, then the client IP is empty.
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- `depth` is ignored if its value is less than or equal to 0.
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!!! example "Example of Depth & X-Forwarded-For"
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If `depth` is set to 2, and the request `X-Forwarded-For` header is `"10.0.0.1,11.0.0.1,12.0.0.1,13.0.0.1"` then the "real" client IP is `"10.0.0.1"` (at depth 4) but the IP used as the criterion is `"12.0.0.1"` (`depth=2`).
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| `X-Forwarded-For` | `depth` | clientIP |
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|-----------------------------------------|---------|--------------|
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| `"10.0.0.1,11.0.0.1,12.0.0.1,13.0.0.1"` | `1` | `"13.0.0.1"` |
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| `"10.0.0.1,11.0.0.1,12.0.0.1,13.0.0.1"` | `3` | `"11.0.0.1"` |
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| `"10.0.0.1,11.0.0.1,12.0.0.1,13.0.0.1"` | `5` | `""` |
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```yaml tab="Docker"
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labels:
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- "traefik.http.middlewares.test-inflightreq.inflightreq.sourcecriterion.ipstrategy.depth=2"
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```
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```yaml tab="Kubernetes"
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apiVersion: traefik.containo.us/v1alpha1
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kind: Middleware
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metadata:
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name: test-inflightreq
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spec:
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inFlightReq:
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sourceCriterion:
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ipStrategy:
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depth: 2
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```
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```yaml tab="Consul Catalog"
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- "traefik.http.middlewares.test-inflightreq.inflightreq.sourcecriterion.ipstrategy.depth=2"
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```
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```yaml tab="File (YAML)"
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http:
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middlewares:
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test-inflightreq:
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inFlightReq:
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sourceCriterion:
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ipStrategy:
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depth: 2
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```
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```toml tab="File (TOML)"
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[http.middlewares]
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[http.middlewares.test-inflightreq.inflightreq]
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[http.middlewares.test-inflightreq.inFlightReq.sourceCriterion.ipStrategy]
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depth = 2
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```
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##### `ipStrategy.excludedIPs`
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`excludedIPs` configures Traefik to scan the `X-Forwarded-For` header and select the first IP not in the list.
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!!! important "If `depth` is specified, `excludedIPs` is ignored."
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!!! example "Example of ExcludedIPs & X-Forwarded-For"
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| `X-Forwarded-For` | `excludedIPs` | clientIP |
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|-----------------------------------------|-----------------------|--------------|
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| `"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"` |
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| `"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"` |
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| `"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"` |
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| `"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"` |
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| `"10.0.0.1,11.0.0.1"` | `"10.0.0.1,11.0.0.1"` | `""` |
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```yaml tab="Docker"
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labels:
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- "traefik.http.middlewares.test-inflightreq.inflightreq.sourcecriterion.ipstrategy.excludedips=127.0.0.1/32, 192.168.1.7"
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```
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```yaml tab="Kubernetes"
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apiVersion: traefik.containo.us/v1alpha1
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kind: Middleware
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metadata:
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name: test-inflightreq
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spec:
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inFlightReq:
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sourceCriterion:
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ipStrategy:
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excludedIPs:
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- 127.0.0.1/32
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- 192.168.1.7
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```
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```yaml tab="Consul Catalog"
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- "traefik.http.middlewares.test-inflightreq.inflightreq.sourcecriterion.ipstrategy.excludedips=127.0.0.1/32, 192.168.1.7"
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```
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```yaml tab="File (YAML)"
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http:
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middlewares:
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test-inflightreq:
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inFlightReq:
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sourceCriterion:
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ipStrategy:
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excludedIPs:
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- "127.0.0.1/32"
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- "192.168.1.7"
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```
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```toml tab="File (TOML)"
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[http.middlewares]
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[http.middlewares.test-inflightreq.inflightreq]
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[http.middlewares.test-inflightreq.inFlightReq.sourceCriterion.ipStrategy]
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excludedIPs = ["127.0.0.1/32", "192.168.1.7"]
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```
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#### `sourceCriterion.requestHeaderName`
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Name of the header used to group incoming requests.
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```yaml tab="Docker"
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labels:
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- "traefik.http.middlewares.test-inflightreq.inflightreq.sourcecriterion.requestheadername=username"
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```
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```yaml tab="Kubernetes"
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apiVersion: traefik.containo.us/v1alpha1
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kind: Middleware
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metadata:
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name: test-inflightreq
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spec:
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inFlightReq:
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sourceCriterion:
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requestHeaderName: username
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```
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```yaml tab="Consul Catalog"
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- "traefik.http.middlewares.test-inflightreq.inflightreq.sourcecriterion.requestheadername=username"
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```
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```yaml tab="File (YAML)"
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http:
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middlewares:
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test-inflightreq:
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inFlightReq:
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sourceCriterion:
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requestHeaderName: username
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```
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```toml tab="File (TOML)"
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[http.middlewares]
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[http.middlewares.test-inflightreq.inflightreq]
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[http.middlewares.test-inflightreq.inFlightReq.sourceCriterion]
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requestHeaderName = "username"
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```
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#### `sourceCriterion.requestHost`
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Whether to consider the request host as the source.
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```yaml tab="Docker"
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labels:
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- "traefik.http.middlewares.test-inflightreq.inflightreq.sourcecriterion.requesthost=true"
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```
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```yaml tab="Kubernetes"
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apiVersion: traefik.containo.us/v1alpha1
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kind: Middleware
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metadata:
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name: test-inflightreq
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spec:
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inFlightReq:
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sourceCriterion:
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requestHost: true
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```
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```yaml tab="Cosul Catalog"
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- "traefik.http.middlewares.test-inflightreq.inflightreq.sourcecriterion.requesthost=true"
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```
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```yaml tab="File (YAML)"
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http:
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middlewares:
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test-inflightreq:
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inFlightReq:
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sourceCriterion:
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requestHost: true
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```
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```toml tab="File (TOML)"
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[http.middlewares]
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[http.middlewares.test-inflightreq.inflightreq]
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[http.middlewares.test-inflightreq.inFlightReq.sourceCriterion]
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requestHost = true
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```
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