open-consul/agent/proxyprocess/proxy.go

102 lines
4.0 KiB
Go

// Package proxy contains logic for agent interaction with proxies,
// primarily "managed" proxies. Managed proxies are proxy processes for
// Connect-compatible endpoints that Consul owns and controls the lifecycle
// for.
//
// This package does not contain the built-in proxy for Connect. The source
// for that is available in the "connect/proxy" package.
package proxyprocess
import (
"github.com/hashicorp/consul/agent/structs"
)
const (
// EnvProxyID is the name of the environment variable that is set for
// managed proxies containing the proxy service ID. This is required along
// with the token to make API requests related to the proxy.
EnvProxyID = "CONNECT_PROXY_ID"
// EnvProxyToken is the name of the environment variable that is passed
// to managed proxies containing the proxy token.
EnvProxyToken = "CONNECT_PROXY_TOKEN"
// EnvSidecarFor is the name of the environment variable that is set for
// sidecar proxies containing the service ID of their target on the local
// agent
EnvSidecarFor = "CONNECT_SIDECAR_FOR"
)
// Proxy is the interface implemented by all types of managed proxies.
//
// Calls to all the functions on this interface must be concurrency safe.
// Please read the documentation carefully on top of each function for expected
// behavior.
//
// Whenever a new proxy type is implemented, please also update proxyExecMode
// and newProxyFromMode and newProxy to support the new proxy.
type Proxy interface {
// Start starts the proxy. If an error is returned then the managed
// proxy registration is rejected. Therefore, this should only fail if
// the configuration of the proxy itself is irrecoverable, and should
// retry starting for other failures.
//
// Starting an already-started proxy should not return an error.
Start() error
// Stop stops the proxy and disallows it from ever being started again.
// This should also clean up any resources used by this Proxy.
//
// If the proxy is not started yet, this should not return an error, but
// it should disallow Start from working again. If the proxy is already
// stopped, this should not return an error.
Stop() error
// Close should clean up any resources associated with this proxy but
// keep it running in the background. Only one of Close or Stop can be
// called.
Close() error
// Equal returns true if the argument is equal to the proxy being called.
// This is called by the manager to determine if a change in configuration
// results in a proxy that needs to be restarted or not. If Equal returns
// false, then the manager will stop the old proxy and start the new one.
// If Equal returns true, the old proxy will remain running and the new
// one will be ignored.
Equal(Proxy) bool
// MarshalSnapshot returns the state that will be stored in a snapshot
// so that Consul can recover the proxy process after a restart. The
// result should only contain primitive values and containers (lists/maps).
//
// MarshalSnapshot does NOT need to store the following fields, since they
// are part of the manager snapshot and will be automatically restored
// for any proxies: proxy ID.
//
// UnmarshalSnapshot is called to restore the receiving Proxy from its
// marshaled state. If UnmarshalSnapshot returns an error, the snapshot
// is ignored and the marshaled snapshot will be lost. The manager will
// log.
//
// This should save/restore enough state to be able to regain management
// of a proxy process as well as to perform the Equal method above. The
// Equal method will be called when a local state sync happens to determine
// if the recovered process should be restarted or not.
MarshalSnapshot() map[string]interface{}
UnmarshalSnapshot(map[string]interface{}) error
}
// proxyExecMode returns the ProxyExecMode for a Proxy instance.
func proxyExecMode(p Proxy) structs.ProxyExecMode {
switch p.(type) {
case *Daemon:
return structs.ProxyExecModeDaemon
case *Noop:
return structs.ProxyExecModeTest
default:
return structs.ProxyExecModeUnspecified
}
}