opa

command module
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 Go to latest Published: Jul 27, 2019 License: Apache-2.0 Imports: 3 Imported by: 0

README

logo Open Policy Agent

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The Open Policy Agent (OPA) is an open source, general-purpose policy engine that enables unified, context-aware policy enforcement across the entire stack.

OPA is hosted by the Cloud Native Computing Foundation (CNCF) as an incubating-level project. If you are an organization that wants to help shape the evolution of technologies that are container-packaged, dynamically-scheduled and microservices-oriented, consider joining the CNCF. For details read the CNCF announcement.

Want to learn more about OPA?

Want to get OPA?

Want to integrate OPA?

  • See GoDoc to integrate OPA with services written in Go.
  • See REST API to integrate OPA with services written in other languages.

Want to contribute to OPA?

How does OPA work?

OPA gives you a high-level declarative language to author and enforce policies across your stack.

With OPA, you define rules that govern how your system should behave. These rules exist to answer questions like:

  • Can user X call operation Y on resource Z?
  • What clusters should workload W be deployed to?
  • What tags must be set on resource R before it's created?

You integrate services with OPA so that these kinds of policy decisions do not have to be hardcoded in your service. Services integrate with OPA by executing queries when policy decisions are needed.

When you query OPA for a policy decision, OPA evaluates the rules and data (which you give it) to produce an answer. The policy decision is sent back as the result of the query.

For example, in a simple API authorization use case:

  • You write rules that allow (or deny) access to your service APIs.
  • Your service queries OPA when it receives API requests.
  • OPA returns allow (or deny) decisions to your service.
  • Your service enforces the decisions by accepting or rejecting requests accordingly.

The examples below show different kinds of policies you can define with OPA as well as different kinds of queries your system can execute against OPA. The example queries are executed inside OPA's REPL which was built to make it easy to develop and test policies.

For concrete examples of how to integrate OPA with systems like Kubernetes, Terraform, Docker, SSH, and more, see openpolicyagent.org.

Example: API Authorization

This example shows how you can enforce access controls over salary information served by a simple HTTP API. In this example, users are allowed to access their own salary as well as the salary of anyone who reports to them.

The management chain is represented in JSON and stored in a file (data.json):

{
    "management_chain": {
        "bob": [
            "ken",
            "janet"
        ],
        "alice": [
            "janet"
        ]
    }
}

Start OPA and load the data.json file:

opa run data.json

Inside the REPL you can define rules and execute queries. Paste the following rules into the REPL.

default allow = false

allow {
    input.method = "GET"
    input.path = ["salary", id]
    input.user_id = id
}

allow {
    input.method = "GET"
    input.path = ["salary", id]
    managers = data.management_chain[id]
    input.user_id = managers[_]
}
Example Queries

Is someone allowed to access their own salary?

> input := {"method": "GET", "path": ["salary", "bob"], "user_id": "bob"}
> allow
true

Display the management chain for Bob:

> data.management_chain["bob"]
[
    "ken",
    "janet"
]

Is Alice allowed to access Bob's salary?

> input := {"method": "GET", "path": ["salary", "bob"], "user_id": "alice"}
> allow
false

Is Janet allowed to access Bob's salary?

> input := {"method": "GET", "path": ["salary", "bob"], "user_id": "janet"}
> allow
true
Example: App Placement

This example shows how you can enforce where apps are deployed inside a simple orchestrator. In this example, apps must be deployed onto clusters that satisfy PCI and jurisdiction requirements.

app_placement[cluster_id] {
    cluster = data.clusters[cluster_id]
    satisfies_jurisdiction(input.app, cluster)
    satisfies_pci(input.app, cluster)
}

satisfies_jurisdiction(app, cluster) {
    not app.tags["requires-eu"]
}

satisfies_jurisdiction(app, cluster) {
    app.tags["requires-eu"]
    startswith(cluster.region, "eu-")
}

satisfies_pci(app, cluster) {
    not app.tags["requires-pci-level"]
}

satisfies_pci(app, cluster) {
    level = to_number(app.tags["requires-pci-level"])
    level >= cluster.tags["pci-level"]
}
Example Queries

Where will this app be deployed?

> input := {"app": {"tags": {"requires-pci-level": "3", "requires-eu": "true"}}}
> app_placement
[
    "prod-eu"
]

Display clusters in EU region:

> startswith(data.clusters[cluster_id].region, "eu-")
+------------+
| cluster_id |
+------------+
| "prod-eu"  |
| "test-eu"  |
+------------+

Display all clusters:

> data.clusters[cluster_id]
+------------+------------------------------------------------+
| cluster_id |           data.clusters[cluster_id]            |
+------------+------------------------------------------------+
| "prod-eu"  | {"region":"eu-central","tags":{"pci-level":2}} |
| "prod-us"  | {"region":"us-east"}                           |
| "test-eu"  | {"region":"eu-west","tags":{"pci-level":4}}    |
| "test-us"  | {"region":"us-west"}                           |
+------------+------------------------------------------------+
Example: SSH Auditing

This example shows how you can audit who has SSH access to hosts within different clusters. We will assume that SSH access is granted via group access in LDAP.

import data.ldap
import data.clusters

ssh_access[[cluster_name, host_id, user_id]] {
    host_id = clusters[cluster_name].hosts[_]
    group_id = ldap.users[user_id].groups[_]
    group_id = clusters[cluster_name].groups[_]
}

prod_users = {user_id | ssh_access[["prod", _, user_id]]}
Example Queries

Who can access production hosts?

> prod_users
[
  "alice",
  "bob"
]

Display all LDAP users:

> data.ldap.users[user_id]
+-------------------------------+---------+
|   data.ldap.users[user_id]    | user_id |
+-------------------------------+---------+
| {"groups":["dev","platform"]} | "alice" |
| {"groups":["dev","ops"]}      | "bob"   |
| {"groups":["dev"]}            | "janet" |
+-------------------------------+---------+

Display all cluster/group pairs:

> data.clusters[cluster_id].groups[_] = group_id
+------------+------------+
| cluster_id |  group_id  |
+------------+------------+
| "test"     | "dev"      |
| "test"     | "ops"      |
| "prod"     | "ops"      |
| "prod"     | "platform" |
+------------+------------+

Does Janet have access to the test cluster?

> ssh_access[["test", _, "janet"]]
true

What are the addresses of the hosts in the test cluster that Janet can access?

> ssh_access[["test", host_id, "janet"]]; addr = data.hosts[host_id].addr
+------------+------------+
|    addr    |  host_id   |
+------------+------------+
| "10.0.0.1" | "host-abc" |
| "10.0.0.2" | "host-cde" |
| "10.0.0.3" | "host-efg" |
+------------+------------+

Further Reading

Presentations
  • Open Policy Agent Introduction @ CloudNativeCon EU 2018: video, slides
  • Rego Deep Dive @ CloudNativeCon EU 2018: video, slides
  • How Netflix Is Solving Authorization Across Their Cloud @ CloudNativeCon US 2017: video, slides.
  • Policy-based Resource Placement in Kubernetes Federation @ LinuxCon Beijing 2017: slides, screencast.
  • Enforcing Bespoke Policies In Kubernetes @ KubeCon US 2017: video, slides.
  • Istio's Mixer: Policy Enforcement with Custom Adapters @ CloudNativeCon US 2017: video, slides.

Security

Security Audit

A third party security audit was performed by Cure53, you can see the full report here

Reporting Security Vulnerabilities

Please report vulnerabilities by email to open-policy-agent-security. We will send a confirmation message to acknowledge that we have received the report and then we will send additional messages to follow up once the issue has been investigated.

Documentation

The Go Gopher

There is no documentation for this package.

Source Files

View all Source files

Directories

Path Synopsis
Package ast declares Rego syntax tree types and also includes a parser and compiler for preparing policies for execution in the policy engine.
 Package ast declares Rego syntax tree types and also includes a parser and compiler for preparing policies for execution in the policy engine.
Package bundle implements bundle loading.
 Package bundle implements bundle loading.
Package cmd contains the entry points for OPA commands.
 Package cmd contains the entry points for OPA commands.
Package config implements OPA configuration file parsing and validation.
 Package config implements OPA configuration file parsing and validation.
Package cover reports coverage on modules.
 Package cover reports coverage on modules.
Package dependencies provides functions for determining the set of ast.Refs that AST elements depend on.
 Package dependencies provides functions for determining the set of ast.Refs that AST elements depend on.
Package download implements low-level OPA bundle downloading.
 Package download implements low-level OPA bundle downloading.
Package format implements formatting of Rego source files.
 Package format implements formatting of Rego source files.
internal
cmd/genopawasm
compiler/wasm
Package wasm contains an IR->WASM compiler backend.
 Package wasm contains an IR->WASM compiler backend.
compiler/wasm/opa
Package opa contains bytecode for the OPA-WASM library.
 Package opa contains bytecode for the OPA-WASM library.
ir
Package ir defines an intermediate representation (IR) for Rego.
 Package ir defines an intermediate representation (IR) for Rego.
leb128
Package leb128 implements LEB128 integer encoding.
 Package leb128 implements LEB128 integer encoding.
manifest
Package manifest implements helper functions for the stored manifest.
 Package manifest implements helper functions for the stored manifest.
planner
Package planner contains a query planner for Rego queries.
 Package planner contains a query planner for Rego queries.
presentation
Package presentation prints results of an expression evaluation in json and tabular formats.
 Package presentation prints results of an expression evaluation in json and tabular formats.
runtime
Package runtime contains utilities to return runtime information on the OPA instance.
 Package runtime contains utilities to return runtime information on the OPA instance.
storage/mock
Package mock defines a fake storage implementation for use in testing.
 Package mock defines a fake storage implementation for use in testing.
strvals
Package strvals provides tools for working with strval lines.
 Package strvals provides tools for working with strval lines.
version
Package version implements helper functions for the stored version.
 Package version implements helper functions for the stored version.
wasm/constant
Package constant contains WASM constant definitions.
 Package constant contains WASM constant definitions.
wasm/encoding
Package encoding implements WASM module reading and writing.
 Package encoding implements WASM module reading and writing.
wasm/instruction
Package instruction defines WASM instruction types.
 Package instruction defines WASM instruction types.
wasm/module
wasm/opcode
Package opcode contains constants and utilities for working with WASM opcodes.
 Package opcode contains constants and utilities for working with WASM opcodes.
wasm/types
Package types defines the WASM value type constants.
 Package types defines the WASM value type constants.
Package loader contains utilities for loading files into OPA.
 Package loader contains utilities for loading files into OPA.
Package metrics contains helpers for performance metric management inside the policy engine.
 Package metrics contains helpers for performance metric management inside the policy engine.
Package plugins implements plugin management for the policy engine.
 Package plugins implements plugin management for the policy engine.
bundle
Package bundle implements bundle downloading.
 Package bundle implements bundle downloading.
discovery
Package discovery implements configuration discovery.
 Package discovery implements configuration discovery.
logs
Package logs implements decision log buffering and uploading.
 Package logs implements decision log buffering and uploading.
rest
Package rest implements a REST client for communicating with remote services.
 Package rest implements a REST client for communicating with remote services.
status
Package status implements status reporting.
 Package status implements status reporting.
Package profiler computes and reports on the time spent on expressions.
 Package profiler computes and reports on the time spent on expressions.
Package rego exposes high level APIs for evaluating Rego policies.
 Package rego exposes high level APIs for evaluating Rego policies.
Package repl implements a Read-Eval-Print-Loop (REPL) for interacting with the policy engine.
 Package repl implements a Read-Eval-Print-Loop (REPL) for interacting with the policy engine.
Package runtime contains the entry point to the policy engine.
 Package runtime contains the entry point to the policy engine.
Package server contains the policy engine's server handlers.
 Package server contains the policy engine's server handlers.
authorizer
Package authorizer provides authorization handlers to the server.
 Package authorizer provides authorization handlers to the server.
identifier
Package identifier provides handlers for associating an identity with incoming requests.
 Package identifier provides handlers for associating an identity with incoming requests.
types
Package types contains request/response types and codes for the server.
 Package types contains request/response types and codes for the server.
writer
Package writer contains utilities for writing responses in the server.
 Package writer contains utilities for writing responses in the server.
Package storage exposes the policy engine's storage layer.
 Package storage exposes the policy engine's storage layer.
inmem
Package inmem implements an in-memory version of the policy engine's storage layer.
 Package inmem implements an in-memory version of the policy engine's storage layer.
test
wasm/cmd
Package tester contains utilities for executing Rego tests.
 Package tester contains utilities for executing Rego tests.
Package topdown provides low-level query evaluation support.
 Package topdown provides low-level query evaluation support.
builtins
Package builtins contains utilities for implementing built-in functions.
 Package builtins contains utilities for implementing built-in functions.
copypropagation
notes
Package types declares data types for Rego values and helper functions to operate on these types.
 Package types declares data types for Rego values and helper functions to operate on these types.
Package util provides generic utilities used throughout the policy engine.
 Package util provides generic utilities used throughout the policy engine.
test
Package test contains utilities used in the policy engine's test suite.
 Package test contains utilities used in the policy engine's test suite.
Package version contains version information that is set at build time.
 Package version contains version information that is set at build time.
Package watch provides the ability to set a watch on a Rego query.
 Package watch provides the ability to set a watch on a Rego query.

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