5452c32f50
This adds the `agent/connect/ca/plugin` library for consuming/serving Connect CA providers as [go-plugin](https://github.com/hashicorp/go-plugin) plugins. This **does not** wire this up in any way to Consul itself, so this will not enable using these plugins yet. ## Why? We want to enable CA providers to be pluggable without modifying Consul so that any CA or PKI system can potentially back the Connect certificates. This CA system may also be used in the future for easier bootstrapping and internal cluster security. ### go-plugin The benefit of `go-plugin` is that for the plugin consumer, the fact that the interface implementation is communicating over multi-process RPC is invisible. Internals of Consul will continue to just use `ca.Provider` interface implementations as if they're local. For plugin _authors_, they simply have to implement the interface. The network/transport/process management issues are handled by go-plugin itself. The CA provider plugins support both `net/rpc` and gRPC transports. This enables easy authoring in any language. go-plugin handles the actual protocol handshake and connection. This is just a feature of go-plugin. `go-plugin` is already in production use for years by Packer, Terraform, Nomad, Vault, and Sentinel. We've shown stability for both desktop and server-side software. It is very mature. ## Implementation Details ### `map[string]interface{}` The `Configure` method passes a `map[string]interface{}`. This map contains only Go primitives and containers of primitives (no funcs, chans, etc.). For `net/rpc` we encode as-is using Gob. For gRPC we marshal to JSON and transmit as a `bytes` type. This is the same approach we take with Vault and other software. Note that this is just the transport protocol, the end software views it fully decoded. ### `x509.Certificate` and `CertificateRequest` We transmit the raw ASN.1 bytes and decode on the other side. Unit tests are verifying we get the same cert/csrs across the wire. ### Testing `go-plugin` exposes test helpers that enable testing the full plugin RPC over real loopback network connections. We test all endpoints for success and error for both `net/rpc` and gRPC. ### Vendoring This PR doesn't introduce vendoring for two reasons: 1. @banks's `f-envoy` branch introduces a lot of these and I didn't want conflict. 2. The library isn't actually used yet so it doesn't introduce compile-time errors (it does introduce test errors). ## Next Steps With this in place, we need to figure out the proper way to actually hook these up to Consul, load them, etc. This discussion can happen elsewhere, since regardless of approach this plugin library implementation is the exact same.
85 lines
2.1 KiB
Protocol Buffer
85 lines
2.1 KiB
Protocol Buffer
/* This proto file contains the service and structures for implementing
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* a Consul CA provider plugin. For clearer documentation on what each
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* RPC method should do, please refer to the Go interface documentation
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* for `agent/connect/ca.Provider`.
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*
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* After implementing this service, the plugin must also output the proper
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* format to stdout for the plugin handshake. Please refer to the Consul
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* documentation for more information.
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*/
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syntax = "proto3";
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option go_package = "github.com/hashicorp/consul/agent/connect/ca/plugin";
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package plugin;
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service CA {
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rpc Configure(ConfigureRequest) returns (Empty);
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rpc GenerateRoot(Empty) returns (Empty);
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rpc ActiveRoot(Empty) returns (ActiveRootResponse);
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rpc GenerateIntermediateCSR(Empty) returns (GenerateIntermediateCSRResponse);
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rpc SetIntermediate(SetIntermediateRequest) returns (Empty);
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rpc ActiveIntermediate(Empty) returns (ActiveIntermediateResponse);
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rpc GenerateIntermediate(Empty) returns (GenerateIntermediateResponse);
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rpc Sign(SignRequest) returns (SignResponse);
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rpc SignIntermediate(SignIntermediateRequest) returns (SignIntermediateResponse);
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rpc CrossSignCA(CrossSignCARequest) returns (CrossSignCAResponse);
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rpc Cleanup(Empty) returns (Empty);
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}
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message ConfigureRequest {
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string cluster_id = 1;
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bool is_root = 2;
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bytes config = 3; // JSON-encoded structure
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}
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message SetIntermediateRequest {
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string intermediate_pem = 1;
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string root_pem = 2;
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}
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message SignRequest {
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bytes csr = 1;
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}
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message SignIntermediateRequest {
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bytes csr = 1;
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}
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message CrossSignCARequest {
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bytes crt = 1;
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}
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message ActiveRootResponse {
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string crt_pem = 1;
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}
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message GenerateIntermediateCSRResponse {
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string csr_pem = 1;
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}
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message ActiveIntermediateResponse {
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string crt_pem = 1;
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}
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message GenerateIntermediateResponse {
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string crt_pem = 1;
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}
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message SignResponse {
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string crt_pem = 1;
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}
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message SignIntermediateResponse {
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string crt_pem = 1;
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}
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message CrossSignCAResponse {
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string crt_pem = 1;
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}
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// Protobufs doesn't allow no req/resp so in the cases where there are
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// no arguments we use the Empty message.
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message Empty {}
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