103 lines
2.8 KiB
Go
103 lines
2.8 KiB
Go
// Package protocol defines the messages agents and the master exchange over
|
|
// their WebSocket connection. Every message is an Envelope whose Payload is
|
|
// one of the payload types below, selected by Type.
|
|
package protocol
|
|
|
|
import (
|
|
"encoding/json"
|
|
"fmt"
|
|
)
|
|
|
|
// Message types sent from agent to master.
|
|
const (
|
|
TypeHello = "hello"
|
|
TypeSnapshot = "snapshot"
|
|
TypeUpsert = "upsert"
|
|
TypeRemove = "remove"
|
|
)
|
|
|
|
// Envelope wraps every message on the wire.
|
|
type Envelope struct {
|
|
Type string `json:"type"`
|
|
Payload json.RawMessage `json:"payload,omitempty"`
|
|
}
|
|
|
|
// Hello is the first message an agent sends on every connection.
|
|
type Hello struct {
|
|
AgentVersion string `json:"agent_version"`
|
|
Hostname string `json:"hostname"`
|
|
SwarmManager bool `json:"swarm_manager"`
|
|
SwarmClusterID string `json:"swarm_cluster_id,omitempty"`
|
|
}
|
|
|
|
// Kind says how a service is deployed.
|
|
type Kind string
|
|
|
|
// Service kinds.
|
|
const (
|
|
KindCompose Kind = "compose"
|
|
KindSwarm Kind = "swarm"
|
|
KindContainer Kind = "container"
|
|
)
|
|
|
|
// Service is one deployable unit as an agent sees it. Which location fields
|
|
// are set depends on Kind.
|
|
type Service struct {
|
|
Kind Kind `json:"kind"`
|
|
ComposeProject string `json:"compose_project,omitempty"`
|
|
ComposeService string `json:"compose_service,omitempty"`
|
|
WorkingDir string `json:"working_dir,omitempty"`
|
|
SwarmService string `json:"swarm_service,omitempty"`
|
|
ContainerName string `json:"container_name,omitempty"`
|
|
Image string `json:"image"`
|
|
Digest string `json:"digest,omitempty"`
|
|
Status string `json:"status"`
|
|
Self bool `json:"self,omitempty"`
|
|
}
|
|
|
|
// Key identifies the service within one agent's report. It is stable across
|
|
// restarts and is what Remove refers to.
|
|
func (s Service) Key() string {
|
|
switch s.Kind {
|
|
case KindCompose:
|
|
return "compose|" + s.ComposeProject + "|" + s.ComposeService
|
|
case KindSwarm:
|
|
return "swarm|" + s.SwarmService
|
|
default:
|
|
return "container|" + s.ContainerName
|
|
}
|
|
}
|
|
|
|
// Snapshot is the agent's complete inventory. Sent after every Hello.
|
|
type Snapshot struct {
|
|
Services []Service `json:"services"`
|
|
}
|
|
|
|
// Upsert reports a service that appeared or changed.
|
|
type Upsert struct {
|
|
Service Service `json:"service"`
|
|
}
|
|
|
|
// Remove reports that the service with Key is gone.
|
|
type Remove struct {
|
|
Key string `json:"key"`
|
|
}
|
|
|
|
// Encode wraps payload in an Envelope of the given type.
|
|
func Encode(typ string, payload any) (Envelope, error) {
|
|
raw, err := json.Marshal(payload)
|
|
if err != nil {
|
|
return Envelope{}, fmt.Errorf("encode %s: %w", typ, err)
|
|
}
|
|
return Envelope{Type: typ, Payload: raw}, nil
|
|
}
|
|
|
|
// Decode unpacks env's payload into T.
|
|
func Decode[T any](env Envelope) (T, error) {
|
|
var v T
|
|
if err := json.Unmarshal(env.Payload, &v); err != nil {
|
|
return v, fmt.Errorf("decode %s: %w", env.Type, err)
|
|
}
|
|
return v, nil
|
|
}
|