f-21: code: ajout d'un system de worker

Signed-off-by: GnomeZworc <nicolas.boufidjeline@g3e.fr>

api/openapi.yaml

@@ -0,0 +1,296 @@
+openapi: "3.1.0"
+info:
+  title: Two API
+  version: "0.1.0"
+  description: REST API for managing VPCs and Subnets in the Two orchestrator.
+
+servers:
+  - url: http://localhost:8080
+    description: Local development server
+
+paths:
+
+  # ── VPC ────────────────────────────────────────────────────────────────────
+
+  /vpcs:
+    get:
+      summary: List all VPCs
+      operationId: listVPCs
+      responses:
+        "200":
+          description: List of VPCs
+          content:
+            application/json:
+              schema:
+                type: array
+                items:
+                  $ref: "#/components/schemas/VPC"
+        "500":
+          $ref: "#/components/responses/InternalError"
+
+    post:
+      summary: Create a VPC
+      operationId: createVPC
+      requestBody:
+        required: true
+        content:
+          application/json:
+            schema:
+              $ref: "#/components/schemas/VPCCreateRequest"
+      responses:
+        "202":
+          description: VPC creation accepted
+          content:
+            application/json:
+              schema:
+                $ref: "#/components/schemas/VPC"
+        "409":
+          description: VPC already exists
+          content:
+            application/json:
+              schema:
+                $ref: "#/components/schemas/Error"
+        "500":
+          $ref: "#/components/responses/InternalError"
+
+  /vpcs/{name}:
+    parameters:
+      - $ref: "#/components/parameters/ResourceName"
+
+    get:
+      summary: Get VPC status and info
+      operationId: getVPC
+      responses:
+        "200":
+          description: VPC found
+          content:
+            application/json:
+              schema:
+                $ref: "#/components/schemas/VPC"
+        "404":
+          $ref: "#/components/responses/NotFound"
+        "500":
+          $ref: "#/components/responses/InternalError"
+
+    delete:
+      summary: Delete a VPC
+      operationId: deleteVPC
+      responses:
+        "202":
+          description: VPC deletion accepted
+          content:
+            application/json:
+              schema:
+                $ref: "#/components/schemas/VPC"
+        "404":
+          $ref: "#/components/responses/NotFound"
+        "409":
+          description: VPC not in a deletable state
+          content:
+            application/json:
+              schema:
+                $ref: "#/components/schemas/Error"
+        "500":
+          $ref: "#/components/responses/InternalError"
+
+  # ── Subnet ─────────────────────────────────────────────────────────────────
+
+  /subnets:
+    get:
+      summary: List all subnets
+      operationId: listSubnets
+      responses:
+        "200":
+          description: List of subnets
+          content:
+            application/json:
+              schema:
+                type: array
+                items:
+                  $ref: "#/components/schemas/Subnet"
+        "500":
+          $ref: "#/components/responses/InternalError"
+
+    post:
+      summary: Create a subnet
+      operationId: createSubnet
+      requestBody:
+        required: true
+        content:
+          application/json:
+            schema:
+              $ref: "#/components/schemas/SubnetCreateRequest"
+      responses:
+        "202":
+          description: Subnet creation accepted
+          content:
+            application/json:
+              schema:
+                $ref: "#/components/schemas/Subnet"
+        "409":
+          description: Subnet already exists
+          content:
+            application/json:
+              schema:
+                $ref: "#/components/schemas/Error"
+        "422":
+          description: Parent VPC does not exist or is not ready
+          content:
+            application/json:
+              schema:
+                $ref: "#/components/schemas/Error"
+        "500":
+          $ref: "#/components/responses/InternalError"
+
+  /subnets/{name}:
+    parameters:
+      - $ref: "#/components/parameters/ResourceName"
+
+    get:
+      summary: Get subnet status and info
+      operationId: getSubnet
+      responses:
+        "200":
+          description: Subnet found
+          content:
+            application/json:
+              schema:
+                $ref: "#/components/schemas/Subnet"
+        "404":
+          $ref: "#/components/responses/NotFound"
+        "500":
+          $ref: "#/components/responses/InternalError"
+
+    delete:
+      summary: Delete a subnet
+      operationId: deleteSubnet
+      responses:
+        "202":
+          description: Subnet deletion accepted
+          content:
+            application/json:
+              schema:
+                $ref: "#/components/schemas/Subnet"
+        "404":
+          $ref: "#/components/responses/NotFound"
+        "409":
+          description: Subnet not in a deletable state
+          content:
+            application/json:
+              schema:
+                $ref: "#/components/schemas/Error"
+        "500":
+          $ref: "#/components/responses/InternalError"
+
+# ── Components ──────────────────────────────────────────────────────────────
+
+components:
+
+  parameters:
+    ResourceName:
+      name: name
+      in: path
+      required: true
+      schema:
+        type: string
+      description: Resource name
+
+  schemas:
+
+    VPCCreateRequest:
+      type: object
+      required: [name]
+      properties:
+        name:
+          type: string
+          description: Unique name for the VPC
+          example: vpc1
+
+    VPC:
+      type: object
+      properties:
+        name:
+          type: string
+          example: vpc1
+        state:
+          type: string
+          enum: [creating, created, deleting, deleted]
+          example: created
+
+    SubnetCreateRequest:
+      type: object
+      required: [name, vpc, vxlan_id, local_ip, gateway_ip, cidr]
+      properties:
+        name:
+          type: string
+          description: Unique name for the subnet
+          example: sn-00001
+        vpc:
+          type: string
+          description: Parent VPC name
+          example: vpc1
+        vxlan_id:
+          type: integer
+          description: VXLAN VNI identifier
+          example: 100
+        local_ip:
+          type: string
+          format: ipv4
+          description: Local VTEP IP address
+          example: "10.0.0.5"
+        gateway_ip:
+          type: string
+          format: ipv4
+          description: Gateway IP for the subnet
+          example: "10.10.10.1"
+        cidr:
+          type: string
+          description: Subnet CIDR block
+          example: "10.10.10.0/24"
+
+    Subnet:
+      type: object
+      properties:
+        name:
+          type: string
+          example: sn-00001
+        state:
+          type: string
+          enum: [creating, created, deleting, deleted]
+          example: created
+        vpc:
+          type: string
+          example: vpc1
+        vxlan_id:
+          type: integer
+          example: 100
+        local_ip:
+          type: string
+          example: "10.0.0.5"
+        gateway_ip:
+          type: string
+          example: "10.10.10.1"
+        cidr:
+          type: string
+          example: "10.10.10.0/24"
+
+    Error:
+      type: object
+      properties:
+        error:
+          type: string
+          example: "resource not found"
+
+  responses:
+    NotFound:
+      description: Resource not found
+      content:
+        application/json:
+          schema:
+            $ref: "#/components/schemas/Error"
+    InternalError:
+      description: Internal server error
+      content:
+        application/json:
+          schema:
+            $ref: "#/components/schemas/Error"

cmd/agent/main.go

@@ -1,17 +1,42 @@
 package main
 
 import (
+	"flag"
 	"fmt"
-	"os"
-)
+	"log"
 
-var (
-	bin_name = os.Args[0]
+	agentapi "git.g3e.fr/syonad/two/internal/api/agent"
+	configuration "git.g3e.fr/syonad/two/internal/config/agent"
+	agentmetrics "git.g3e.fr/syonad/two/internal/prometheus/agent"
+	"git.g3e.fr/syonad/two/pkg/db/kv"
+	promserver "git.g3e.fr/syonad/two/pkg/prometheus"
+	"git.g3e.fr/syonad/two/pkg/worker"
+	"github.com/prometheus/client_golang/prometheus"
 )
 
 func main() {
+	confFile := flag.String("config", "/etc/two/agent.yml", "config file path")
+	flag.Parse()
 
-	fmt.Printf("%s: Start process\n", bin_name)
+	cfg, err := configuration.LoadConfig(*confFile)
+	if err != nil {
+		log.Fatalf("failed to load config: %v", err)
+	}
 
-	os.Exit(0)
+	db := kv.InitDB(kv.Config{Path: cfg.Database.Path}, true)
+	defer db.Close()
+
+	q := worker.New(cfg.Worker.BufferSize)
+	q.Start(cfg.Worker.Count)
+
+	registry := prometheus.NewRegistry()
+	registry.MustRegister(agentmetrics.NewAgentCollector(db))
+
+	apiAddr := fmt.Sprintf("%s:%d", cfg.Api.Address, cfg.Api.Port)
+	promAddr := fmt.Sprintf("%s:%d", cfg.Prometheus.Address, cfg.Prometheus.Port)
+
+	go agentapi.New(q).Start(apiAddr)
+	go promserver.Start(promAddr, registry)
+
+	select {}
 }

go.mod

@@ -5,6 +5,7 @@ go 1.24.0
 toolchain go1.24.11
 
 require (
+	github.com/beorn7/perks v1.0.1 // indirect
 	github.com/cespare/xxhash/v2 v2.3.0 // indirect
 	github.com/coreos/go-systemd/v22 v22.6.0 // indirect
 	github.com/dgraph-io/badger/v4 v4.8.0 // indirect
@@ -17,7 +18,12 @@ require (
 	github.com/godbus/dbus/v5 v5.1.0 // indirect
 	github.com/google/flatbuffers v25.2.10+incompatible // indirect
 	github.com/klauspost/compress v1.18.0 // indirect
+	github.com/munnerz/goautoneg v0.0.0-20191010083416-a7dc8b61c822 // indirect
 	github.com/pelletier/go-toml/v2 v2.2.4 // indirect
+	github.com/prometheus/client_golang v1.23.2 // indirect
+	github.com/prometheus/client_model v0.6.2 // indirect
+	github.com/prometheus/common v0.66.1 // indirect
+	github.com/prometheus/procfs v0.16.1 // indirect
 	github.com/sagikazarmark/locafero v0.11.0 // indirect
 	github.com/sourcegraph/conc v0.3.1-0.20240121214520-5f936abd7ae8 // indirect
 	github.com/spf13/afero v1.15.0 // indirect
@@ -31,9 +37,10 @@ require (
 	go.opentelemetry.io/otel v1.37.0 // indirect
 	go.opentelemetry.io/otel/metric v1.37.0 // indirect
 	go.opentelemetry.io/otel/trace v1.37.0 // indirect
+	go.yaml.in/yaml/v2 v2.4.2 // indirect
 	go.yaml.in/yaml/v3 v3.0.4 // indirect
-	golang.org/x/net v0.41.0 // indirect
+	golang.org/x/net v0.43.0 // indirect
 	golang.org/x/sys v0.39.0 // indirect
 	golang.org/x/text v0.28.0 // indirect
-	google.golang.org/protobuf v1.36.6 // indirect
+	google.golang.org/protobuf v1.36.8 // indirect
 )

go.sum

@@ -1,3 +1,5 @@
+github.com/beorn7/perks v1.0.1 h1:VlbKKnNfV8bJzeqoa4cOKqO6bYr3WgKZxO8Z16+hsOM=
+github.com/beorn7/perks v1.0.1/go.mod h1:G2ZrVWU2WbWT9wwq4/hrbKbnv/1ERSJQ0ibhJ6rlkpw=
 github.com/cespare/xxhash/v2 v2.3.0 h1:UL815xU9SqsFlibzuggzjXhog7bL6oX9BbNZnL2UFvs=
 github.com/cespare/xxhash/v2 v2.3.0/go.mod h1:VGX0DQ3Q6kWi7AoAeZDth3/j3BFtOZR5XLFGgcrjCOs=
 github.com/coreos/go-systemd/v22 v22.6.0 h1:aGVa/v8B7hpb0TKl0MWoAavPDmHvobFe5R5zn0bCJWo=
@@ -23,8 +25,18 @@ github.com/google/flatbuffers v25.2.10+incompatible h1:F3vclr7C3HpB1k9mxCGRMXq6F
 github.com/google/flatbuffers v25.2.10+incompatible/go.mod h1:1AeVuKshWv4vARoZatz6mlQ0JxURH0Kv5+zNeJKJCa8=
 github.com/klauspost/compress v1.18.0 h1:c/Cqfb0r+Yi+JtIEq73FWXVkRonBlf0CRNYc8Zttxdo=
 github.com/klauspost/compress v1.18.0/go.mod h1:2Pp+KzxcywXVXMr50+X0Q/Lsb43OQHYWRCY2AiWywWQ=
+github.com/munnerz/goautoneg v0.0.0-20191010083416-a7dc8b61c822 h1:C3w9PqII01/Oq1c1nUAm88MOHcQC9l5mIlSMApZMrHA=
+github.com/munnerz/goautoneg v0.0.0-20191010083416-a7dc8b61c822/go.mod h1:+n7T8mK8HuQTcFwEeznm/DIxMOiR9yIdICNftLE1DvQ=
 github.com/pelletier/go-toml/v2 v2.2.4 h1:mye9XuhQ6gvn5h28+VilKrrPoQVanw5PMw/TB0t5Ec4=
 github.com/pelletier/go-toml/v2 v2.2.4/go.mod h1:2gIqNv+qfxSVS7cM2xJQKtLSTLUE9V8t9Stt+h56mCY=
+github.com/prometheus/client_golang v1.23.2 h1:Je96obch5RDVy3FDMndoUsjAhG5Edi49h0RJWRi/o0o=
+github.com/prometheus/client_golang v1.23.2/go.mod h1:Tb1a6LWHB3/SPIzCoaDXI4I8UHKeFTEQ1YCr+0Gyqmg=
+github.com/prometheus/client_model v0.6.2 h1:oBsgwpGs7iVziMvrGhE53c/GrLUsZdHnqNwqPLxwZyk=
+github.com/prometheus/client_model v0.6.2/go.mod h1:y3m2F6Gdpfy6Ut/GBsUqTWZqCUvMVzSfMLjcu6wAwpE=
+github.com/prometheus/common v0.66.1 h1:h5E0h5/Y8niHc5DlaLlWLArTQI7tMrsfQjHV+d9ZoGs=
+github.com/prometheus/common v0.66.1/go.mod h1:gcaUsgf3KfRSwHY4dIMXLPV0K/Wg1oZ8+SbZk/HH/dA=
+github.com/prometheus/procfs v0.16.1 h1:hZ15bTNuirocR6u0JZ6BAHHmwS1p8B4P6MRqxtzMyRg=
+github.com/prometheus/procfs v0.16.1/go.mod h1:teAbpZRB1iIAJYREa1LsoWUXykVXA1KlTmWl8x/U+Is=
 github.com/sagikazarmark/locafero v0.11.0 h1:1iurJgmM9G3PA/I+wWYIOw/5SyBtxapeHDcg+AAIFXc=
 github.com/sagikazarmark/locafero v0.11.0/go.mod h1:nVIGvgyzw595SUSUE6tvCp3YYTeHs15MvlmU87WwIik=
 github.com/sourcegraph/conc v0.3.1-0.20240121214520-5f936abd7ae8 h1:+jumHNA0Wrelhe64i8F6HNlS8pkoyMv5sreGx2Ry5Rw=
@@ -51,10 +63,14 @@ go.opentelemetry.io/otel/metric v1.37.0 h1:mvwbQS5m0tbmqML4NqK+e3aDiO02vsf/Wgbsd
 go.opentelemetry.io/otel/metric v1.37.0/go.mod h1:04wGrZurHYKOc+RKeye86GwKiTb9FKm1WHtO+4EVr2E=
 go.opentelemetry.io/otel/trace v1.37.0 h1:HLdcFNbRQBE2imdSEgm/kwqmQj1Or1l/7bW6mxVK7z4=
 go.opentelemetry.io/otel/trace v1.37.0/go.mod h1:TlgrlQ+PtQO5XFerSPUYG0JSgGyryXewPGyayAWSBS0=
+go.yaml.in/yaml/v2 v2.4.2 h1:DzmwEr2rDGHl7lsFgAHxmNz/1NlQ7xLIrlN2h5d1eGI=
+go.yaml.in/yaml/v2 v2.4.2/go.mod h1:081UH+NErpNdqlCXm3TtEran0rJZGxAYx9hb/ELlsPU=
 go.yaml.in/yaml/v3 v3.0.4 h1:tfq32ie2Jv2UxXFdLJdh3jXuOzWiL1fo0bu/FbuKpbc=
 go.yaml.in/yaml/v3 v3.0.4/go.mod h1:DhzuOOF2ATzADvBadXxruRBLzYTpT36CKvDb3+aBEFg=
 golang.org/x/net v0.41.0 h1:vBTly1HeNPEn3wtREYfy4GZ/NECgw2Cnl+nK6Nz3uvw=
 golang.org/x/net v0.41.0/go.mod h1:B/K4NNqkfmg07DQYrbwvSluqCJOOXwUjeb/5lOisjbA=
+golang.org/x/net v0.43.0 h1:lat02VYK2j4aLzMzecihNvTlJNQUq316m2Mr9rnM6YE=
+golang.org/x/net v0.43.0/go.mod h1:vhO1fvI4dGsIjh73sWfUVjj3N7CA9WkKJNQm2svM6Jg=
 golang.org/x/sys v0.2.0/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
 golang.org/x/sys v0.10.0/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
 golang.org/x/sys v0.34.0 h1:H5Y5sJ2L2JRdyv7ROF1he/lPdvFsd0mJHFw2ThKHxLA=
@@ -65,4 +81,6 @@ golang.org/x/text v0.28.0 h1:rhazDwis8INMIwQ4tpjLDzUhx6RlXqZNPEM0huQojng=
 golang.org/x/text v0.28.0/go.mod h1:U8nCwOR8jO/marOQ0QbDiOngZVEBB7MAiitBuMjXiNU=
 google.golang.org/protobuf v1.36.6 h1:z1NpPI8ku2WgiWnf+t9wTPsn6eP1L7ksHUlkfLvd9xY=
 google.golang.org/protobuf v1.36.6/go.mod h1:jduwjTPXsFjZGTmRluh+L6NjiWu7pchiJ2/5YcXBHnY=
+google.golang.org/protobuf v1.36.8 h1:xHScyCOEuuwZEc6UtSOvPbAT4zRh0xcNRYekJwfqyMc=
+google.golang.org/protobuf v1.36.8/go.mod h1:fuxRtAxBytpl4zzqUh6/eyUujkJdNiuEkXntxiD/uRU=
 gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=

internal/api/agent/server.go

@@ -0,0 +1,26 @@
+package agentapi
+
+import (
+	"log"
+	"net/http"
+
+	"git.g3e.fr/syonad/two/pkg/worker"
+)
+
+type Server struct {
+	queue *worker.Queue
+}
+
+func New(queue *worker.Queue) *Server {
+	return &Server{queue: queue}
+}
+
+func (s *Server) Start(address string) {
+	mux := http.NewServeMux()
+	mux.HandleFunc("/vpcs", s.VpcsHandler)
+	mux.HandleFunc("/vpcs/", s.VpcByNameHandler)
+	mux.HandleFunc("/subnets", s.SubnetsHandler)
+	mux.HandleFunc("/subnets/", s.SubnetByNameHandler)
+	log.Printf("API server listening on %s", address)
+	log.Fatal(http.ListenAndServe(address, mux))
+}

internal/api/agent/subnet.go

@@ -0,0 +1,30 @@
+package agentapi
+
+import (
+	"encoding/json"
+	"net/http"
+	"strings"
+)
+
+func (s *Server) SubnetByNameHandler(w http.ResponseWriter, r *http.Request) {
+	name := strings.TrimPrefix(r.URL.Path, "/subnets/")
+	if name == "" {
+		http.NotFound(w, r)
+		return
+	}
+	w.Header().Set("Content-Type", "application/json")
+	switch r.Method {
+	case http.MethodGet:
+		w.WriteHeader(http.StatusOK)
+		json.NewEncoder(w).Encode(map[string]string{"name": name})
+	case http.MethodDelete:
+		s.queue.Submit(func() {
+			deleteSubnet(name)
+		})
+		w.WriteHeader(http.StatusAccepted)
+	default:
+		http.Error(w, "method not allowed", http.StatusMethodNotAllowed)
+	}
+}
+
+func deleteSubnet(name string) {}

internal/api/agent/subnets.go

@@ -0,0 +1,24 @@
+package agentapi
+
+import (
+	"encoding/json"
+	"net/http"
+)
+
+func (s *Server) SubnetsHandler(w http.ResponseWriter, r *http.Request) {
+	w.Header().Set("Content-Type", "application/json")
+	switch r.Method {
+	case http.MethodGet:
+		w.WriteHeader(http.StatusOK)
+		json.NewEncoder(w).Encode([]interface{}{})
+	case http.MethodPost:
+		s.queue.Submit(func() {
+			createSubnet()
+		})
+		w.WriteHeader(http.StatusAccepted)
+	default:
+		http.Error(w, "method not allowed", http.StatusMethodNotAllowed)
+	}
+}
+
+func createSubnet() {}

internal/api/agent/vpc.go

@@ -0,0 +1,30 @@
+package agentapi
+
+import (
+	"encoding/json"
+	"net/http"
+	"strings"
+)
+
+func (s *Server) VpcByNameHandler(w http.ResponseWriter, r *http.Request) {
+	name := strings.TrimPrefix(r.URL.Path, "/vpcs/")
+	if name == "" {
+		http.NotFound(w, r)
+		return
+	}
+	w.Header().Set("Content-Type", "application/json")
+	switch r.Method {
+	case http.MethodGet:
+		w.WriteHeader(http.StatusOK)
+		json.NewEncoder(w).Encode(map[string]string{"name": name})
+	case http.MethodDelete:
+		s.queue.Submit(func() {
+			deleteVpc(name)
+		})
+		w.WriteHeader(http.StatusAccepted)
+	default:
+		http.Error(w, "method not allowed", http.StatusMethodNotAllowed)
+	}
+}
+
+func deleteVpc(name string) {}

internal/api/agent/vpcs.go

@@ -0,0 +1,24 @@
+package agentapi
+
+import (
+	"encoding/json"
+	"net/http"
+)
+
+func (s *Server) VpcsHandler(w http.ResponseWriter, r *http.Request) {
+	w.Header().Set("Content-Type", "application/json")
+	switch r.Method {
+	case http.MethodGet:
+		w.WriteHeader(http.StatusOK)
+		json.NewEncoder(w).Encode([]interface{}{})
+	case http.MethodPost:
+		s.queue.Submit(func() {
+			createVpc()
+		})
+		w.WriteHeader(http.StatusAccepted)
+	default:
+		http.Error(w, "method not allowed", http.StatusMethodNotAllowed)
+	}
+}
+
+func createVpc() {}

internal/config/agent/struct.go

@@ -8,6 +8,18 @@ type Config struct {
 	Database struct {
 		Path string `mapstructure:"path"`
 	} `mapstructure:"database"`
+	Api struct {
+		Address string `mapstructure:"address"`
+		Port    int    `mapstructure:"port"`
+	} `mapstructure:"api"`
+	Prometheus struct {
+		Address string `mapstructure:"address"`
+		Port    int    `mapstructure:"port"`
+	} `mapstructure:"prometheus"`
+	Worker struct {
+		Count      int `mapstructure:"count"`
+		BufferSize int `mapstructure:"buffer_size"`
+	} `mapstructure:"worker"`
 }
 
 func LoadConfig(path string) (*Config, error) {
@@ -16,6 +28,12 @@ func LoadConfig(path string) (*Config, error) {
 	v.SetConfigType("yaml")
 
 	v.SetDefault("database.path", "/var/lib/two/data/")
+	v.SetDefault("api.address", "")
+	v.SetDefault("api.port", 8080)
+	v.SetDefault("prometheus.address", "")
+	v.SetDefault("prometheus.port", 9090)
+	v.SetDefault("worker.count", 4)
+	v.SetDefault("worker.buffer_size", 100)
 
 	v.ReadInConfig()
 

internal/prometheus/agent/collector.go

@@ -0,0 +1,67 @@
+package agentmetrics
+
+import (
+	"strings"
+
+	"git.g3e.fr/syonad/two/pkg/db/kv"
+	"github.com/dgraph-io/badger/v4"
+	"github.com/prometheus/client_golang/prometheus"
+)
+
+var allStates = []string{"creating", "created", "deleting", "deleted"}
+
+// AgentCollector implements prometheus.Collector and exposes agent metrics
+// by querying the BadgerDB on each scrape.
+type AgentCollector struct {
+	db           *badger.DB
+	vpcsTotal    *prometheus.Desc
+	subnetsTotal *prometheus.Desc
+}
+
+func NewAgentCollector(db *badger.DB) *AgentCollector {
+	return &AgentCollector{
+		db: db,
+		vpcsTotal: prometheus.NewDesc(
+			"syonad_vpcs_total",
+			"Number of VPCs by state.",
+			[]string{"state"}, nil,
+		),
+		subnetsTotal: prometheus.NewDesc(
+			"syonad_subnets_total",
+			"Number of subnets by state.",
+			[]string{"state"}, nil,
+		),
+	}
+}
+
+func (c *AgentCollector) Describe(ch chan<- *prometheus.Desc) {
+	ch <- c.vpcsTotal
+	ch <- c.subnetsTotal
+}
+
+func (c *AgentCollector) Collect(ch chan<- prometheus.Metric) {
+	c.collectStates(ch, "vpc/", c.vpcsTotal)
+	c.collectStates(ch, "subnet/", c.subnetsTotal)
+}
+
+// collectStates counts resources under the given DB prefix by their state value
+// and emits one gauge per state label.
+func (c *AgentCollector) collectStates(ch chan<- prometheus.Metric, prefix string, desc *prometheus.Desc) {
+	counts := make(map[string]float64, len(allStates))
+	for _, s := range allStates {
+		counts[s] = 0
+	}
+
+	items, err := kv.ListByPrefix(c.db, prefix)
+	if err == nil {
+		for key, val := range items {
+			if strings.HasSuffix(key, "/state") {
+				counts[val]++
+			}
+		}
+	}
+
+	for _, state := range allStates {
+		ch <- prometheus.MustNewConstMetric(desc, prometheus.GaugeValue, counts[state], state)
+	}
+}

pkg/db/kv/listByPrefix.go

@@ -0,0 +1,33 @@
+package kv
+
+import (
+	"github.com/dgraph-io/badger/v4"
+)
+
+// ListByPrefix returns all key-value pairs whose key starts with prefix.
+func ListByPrefix(db *badger.DB, prefix string) (map[string]string, error) {
+	result := make(map[string]string)
+	p := []byte(prefix)
+
+	err := db.View(func(txn *badger.Txn) error {
+		opts := badger.DefaultIteratorOptions
+		opts.PrefetchSize = 10
+
+		it := txn.NewIterator(opts)
+		defer it.Close()
+
+		for it.Seek(p); it.ValidForPrefix(p); it.Next() {
+			item := it.Item()
+			key := string(item.Key())
+
+			val, err := item.ValueCopy(nil)
+			if err != nil {
+				return err
+			}
+			result[key] = string(val)
+		}
+		return nil
+	})
+
+	return result, err
+}

pkg/prometheus/server.go

@@ -0,0 +1,20 @@
+package promserver
+
+import (
+	"log"
+	"net/http"
+
+	"github.com/prometheus/client_golang/prometheus"
+	"github.com/prometheus/client_golang/prometheus/promhttp"
+)
+
+// Start launches the Prometheus metrics HTTP server on the given address.
+// The provided registry is used to expose metrics at /metrics.
+func Start(address string, registry *prometheus.Registry) {
+	mux := http.NewServeMux()
+	mux.Handle("/metrics", promhttp.HandlerFor(registry, promhttp.HandlerOpts{
+		EnableOpenMetrics: true,
+	}))
+	log.Printf("Prometheus server listening on %s", address)
+	log.Fatal(http.ListenAndServe(address, mux))
+}

pkg/worker/queue.go

@@ -0,0 +1,33 @@
+package worker
+
+import "log"
+
+// Task is a function to be executed asynchronously by a worker.
+type Task func()
+
+// Queue is a FIFO channel-backed task queue consumed by worker goroutines.
+type Queue struct {
+	tasks chan Task
+}
+
+// New creates a Queue with the given channel buffer size.
+func New(bufferSize int) *Queue {
+	return &Queue{tasks: make(chan Task, bufferSize)}
+}
+
+// Submit enqueues a task. Blocks if the queue is full.
+func (q *Queue) Submit(t Task) {
+	q.tasks <- t
+}
+
+// Start launches n worker goroutines that consume and execute tasks.
+func (q *Queue) Start(n int) {
+	log.Printf("worker: starting %d workers", n)
+	for i := range n {
+		go func(id int) {
+			for task := range q.tasks {
+				task()
+			}
+		}(i)
+	}
+}