open-consul/website/source/docs/agent/sentinel.html.markdown.erb
Chris Marchesi 2c0d46282e website: fix Sentinel time-of-day policy (#5930)
The policy in the time-of-day Sentinel example incorrectly references
the top-level time.hour constant. This is actually the same as the
time.Hour Go value, so in other words, 3600000000000 (the int64 value
representing the time in nanoseconds).

This is corrected by just using time.now.hour instead.
2019-06-06 14:31:54 -06:00

93 lines
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---
layout: "docs"
page_title: "Sentinel in Consul"
sidebar_current: "docs-agent-sentinel"
description: |-
Consul Enterprise uses Sentinel to augment the built-in ACL system to provide advanced policy enforcement. Sentinel policies can currently execute on KV modify and service registration.
---
# Sentinel Overview
[//]: # ( ~> The Sentinel functionality described here is available only in )
[//]: # ( [Consul Enterprise](https://www.hashicorp.com/products/consul/) version 1.0.0 and later. )
<%= enterprise_alert :consul %>
Consul 1.0 adds integration with [Sentinel](https://hashicorp.com/sentinel) for policy enforcement.
Sentinel policies help extend the ACL system in Consul beyond the static "read", "write", and "deny"
policies to support full conditional logic and integration with external systems.
## Sentinel in Consul
Sentinel policies are applied during writes to the KV Store.
An optional `sentinel` field specifying code and enforcement level can be added to [ACL policy definitions](/docs/agent/acl-rules.html#sentinel-integration) for Consul KV. The following policy ensures that the value written during a KV update must end with "dc1".
```text
key "datacenter_name" {
policy = "write"
sentinel {
code = <<EOF
import "strings"
main = rule { strings.has_suffix(value, "dc1") }
EOF
enforcementlevel = "soft-mandatory"
}
}
```
If the `enforcementlevel` property is not set, it defaults to "hard-mandatory".
## Imports
Consul imports all the [standard imports](https://docs.hashicorp.com/sentinel/imports/)
from Sentinel. All functions in these imports are available to be used in policies.
## Injected Variables
Consul passes some context as variables into Sentinel, which are available to use inside any policies you write.
#### Variables injected during KV store writes
| Variable Name | Type | Description |
| ------------- | -------- | ----------- |
| `key` | `string` | Key being written |
| `value` | `string` | Value being written |
| `flags` | `uint64` | [Flags](/api/kv.html#flags) |
## Sentinel Examples
The following are two examples of ACL policies with Sentinel rules.
### Required Key Suffix
Any values stored under the key prefix "dc1" must end with "dev"
```text
key "dc1" {
policy = "write"
sentinel {
code = <<EOF
import "strings"
main = rule { strings.has_suffix(value, "dev") }
EOF
}
}
```
### Restrited Update Time
The key "haproxy_version" can only be updated during business hours.
```text
key "haproxy_version" {
policy = "write"
sentinel {
code = <<EOF
import "time"
main = rule { time.now.hour > 8 and time.now.hour < 17 }
EOF
}
}
```