Files
DriverVault/API Server/internal/plugins/README.md
T
tajniak81andClaude Opus 5 9bd5c523c4 Plugins: the global layer moves into the database, beside the other two
The integration cascade stored its top layer differently from the two below
it: org (L2) and user (L3) plugin config lived in PocketBase, in a
pluginSettings field, while the global (L1) layer sat in a plugins.json
next to the binary. That split was accretion rather than design - the file
was the whole store in the v1 MVP, and the per-tenant layers were later
built on PocketBase and layered on top of it instead of replacing it.

It also cost something real. plugins.json was a second state store with
different durability from pb_data: its own volume, its own ownership, its
own backup. Losing pb_data is unmissable; losing api_data was silent, which
is how "every plugin comes back disabled after a redeploy" happened.

L1 now lives in the app_settings collection - one record keyed "global",
holding its settings in a pluginSettings field, the same mechanism and the
same field name the layers below use. The documents still differ in shape,
because only L1 carries enable state and the registration of external
plugins, but the storage is no longer a special case.

The Manager grows a Store seam (PocketBase in production, file for the
import, memory for tests) and, more importantly, a loaded gate. Settings in
a database mean the store can be unreachable at boot - a cold stack, or a
service account still to be set from the panel. That must not read as "no
plugins configured", or the first save would write emptiness over real
settings. So until a read succeeds the Manager stays unloaded, every
mutation is refused, /api/admin/plugins* answers 503, and a background
retry backs off to two minutes. The same gate covers a document that will
not parse: it is never replaced by one built from an empty map, which is a
stronger guarantee than the .corrupt backup it replaces.

Writing to a store also revealed a hole in the previous fix. Classifying a
save failure as errPersist was left to each Store, and a store that
returned a plain error would fall through to the "saved, but the plugin
failed to start" branch and be reported as a 200 - the same silent-success
bug through a different door. The Manager now classifies, whatever the
Store returns; a test pins it.

Upgrades are automatic: on the first boot that finds no settings in the
database, an existing plugins.json is imported and renamed to
plugins.json.migrated. The import is refused if the store is merely
unreachable, or if the file does not parse, so a stale or broken file can
never overwrite live settings. /data is still needed - the panel rewrites
.env there when it retargets PocketBase - but plugin settings no longer
depend on it.

21 tests in internal/plugins cover both stores, including the production
path against a fake PocketBase: create-then-update of the singleton,
round-trip across a restart, an outage that leaves settings intact, a
missing collection reading as not-ready rather than empty, and the import
running exactly once. go build, go vet and go test ./... pass. Schema
changes are mirrored into scripts/setup-pocketbase.mjs as that file
requires. Not verified: no Docker CLI here, so no image was built and the
bootstrap of app_settings against a real PocketBase is untested outside the
fake.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
2026-08-21 16:52:47 +02:00

13 KiB

Building DriverVault Plugins

A plugin integrates an external third-party service (vehicle data, parts catalogs, notifications, file storage, …) behind one uniform contract. There are two kinds:

Kind Written as Added by Rebuild? Use when
built-in Go code in this repo a rebuild yes first-party, high-trust, type-safe connectors
external any HTTP service registering a URL at runtime no third-party / less-trusted / independently deployed

Both implement the same behaviour; the server treats them identically. Enable state and per-plugin config persist to PocketBase and load on boot. Every plugin is managed by a superadmin from the panel (/) or the /api/admin/plugins* API.


The contract

All plugins satisfy the Go interface in plugin.go:

type Plugin interface {
    Descriptor() Descriptor
    Init(ctx context.Context, config map[string]string) error
    HealthCheck(ctx context.Context) Health
    Invoke(ctx context.Context, action string, params json.RawMessage) (json.RawMessage, error)
    Shutdown(ctx context.Context) error
}
  • Descriptor — static metadata (name, provider, version, capabilities, auth type, config fields). Drives the panel UI.
  • Init — called with the resolved config (secrets included) whenever the plugin is enabled or its config changes. Prepare clients/tokens here.
  • HealthCheck — probe the upstream and classify: Health{Status, LatencyMs, Detail} where Status is StatusOK / StatusDegraded / StatusDown.
  • Invoke — run a named capability. There is no generic invoke endpoint yet, but this is live: the integration routes and the vehicle-provider layer call it through Manager.InvokeWith / InvokeBatchWith, so implement it properly. It must be safe for concurrent use — the live instance is shared across requests, and InvokeBatchWith runs a batch of actions in parallel on one instance.
  • Shutdown — release resources.

Descriptor & config fields

Descriptor{
    Name:         "acme",              // unique id, [a-z0-9-]
    Provider:     "ACME Corp",         // human label
    Version:      "1.0.0",
    Kind:         plugins.KindBuiltin, // or KindExternal
    Capabilities: []plugins.Capability{
        {ID: "widgets.list", Method: "GET", Endpoint: "/widgets", Description: "List widgets."},
    },
    AuthType:     plugins.AuthAPIKey,  // None | APIKey | Basic | OAuth2 | Webhook (metadata only)
    ConfigFields: []plugins.ConfigField{
        {Key: "apiKey", Label: "API key", Type: "password", Required: true, Secret: true,
         Help: "Found under ACME → Settings → API."},
        {Key: "region", Label: "Region", Type: "text", Help: "e.g. eu-west-1"},
    },
}

ConfigField.Type is "text", "password", or "number" (form input hint). Set Secret: true for credentials — the server never echoes them back in clear; the panel shows a mask (••••••••), and on save a field left at the mask keeps its stored value (so operators don't retype secrets). Required: true fields must be non-empty before the plugin can be enabled.


Building a built-in plugin

  1. Create a package under internal/plugins/builtin/<name>/.
  2. Implement Plugin and register it in init().
  3. Blank-import your package from builtin/builtin.go.
  4. Rebuild the server.

Minimal example — internal/plugins/builtin/acme/acme.go

package acme

import (
    "context"
    "encoding/json"
    "net/http"
    "strings"
    "time"

    "drivervault/apiserver/internal/plugins"
)

func init() {
    plugins.Register("acme", func() plugins.Plugin { return &Plugin{} })
}

type Plugin struct {
    apiKey string
    region string
    client *http.Client
}

func (p *Plugin) Descriptor() plugins.Descriptor {
    return plugins.Descriptor{
        Name: "acme", Provider: "ACME Corp", Version: "1.0.0",
        Kind: plugins.KindBuiltin, AuthType: plugins.AuthAPIKey,
        Capabilities: []plugins.Capability{
        {ID: "widgets.list", Method: "GET", Endpoint: "/widgets", Description: "List widgets."},
    },
        ConfigFields: []plugins.ConfigField{
            {Key: "apiKey", Label: "API key", Type: "password", Required: true, Secret: true},
            {Key: "region", Label: "Region", Type: "text"},
        },
    }
}

func (p *Plugin) Init(_ context.Context, config map[string]string) error {
    p.apiKey = strings.TrimSpace(config["apiKey"])
    p.region = strings.TrimSpace(config["region"])
    p.client = &http.Client{Timeout: 10 * time.Second}
    return nil
}

func (p *Plugin) HealthCheck(ctx context.Context) plugins.Health {
    start := time.Now()
    req, _ := http.NewRequestWithContext(ctx, http.MethodGet, "https://api.acme.example/ping", nil)
    req.Header.Set("Authorization", "Bearer "+p.apiKey)
    resp, err := p.client.Do(req)
    lat := time.Since(start).Milliseconds()
    if err != nil {
        return plugins.Health{Status: plugins.StatusDown, LatencyMs: lat, Detail: err.Error()}
    }
    defer resp.Body.Close()
    if resp.StatusCode >= 200 && resp.StatusCode < 300 {
        return plugins.Health{Status: plugins.StatusOK, LatencyMs: lat, Detail: "reachable"}
    }
    return plugins.Health{Status: plugins.StatusDown, LatencyMs: lat, Detail: "HTTP " + resp.Status}
}

func (p *Plugin) Invoke(ctx context.Context, action string, params json.RawMessage) (json.RawMessage, error) {
    // Implement your capabilities; return normalized JSON. Must be safe for
    // concurrent use — one instance serves many requests.
    return json.RawMessage(`{"ok":true}`), nil
}

func (p *Plugin) Shutdown(context.Context) error { return nil }

Register it for compilation — internal/plugins/builtin/builtin.go

import (
    _ "drivervault/apiserver/internal/plugins/builtin/acme"
)

Rebuild

cd "API Server"
go build -o bin/api-server.exe ./cmd/server

Restart the server. The plugin appears in the panel's Plugins card, disabled by default.

DriverVault ships two built-in connectors today — toyota (Toyota Connected / MyToyota, read-only vehicle data) and anker-solix (Anker Solix V1 EV charger) — both blank-imported from builtin/builtin.go. The external kind below needs no rebuild and is the easier place to start a new one.


Building an external plugin (no rebuild)

An external plugin is any HTTP service you host (Go recommended, but any language works). You register its base URL at runtime; the server drives it over a tiny JSON contract.

The HTTP contract

Method & path Purpose Response
GET {base}/manifest describe the plugin (optional) {provider, version, capabilities, authType, configFields}
GET {base}/health health probe (required) 2xx = healthy; optional body {status, detail}
POST {base}/invoke run a capability (optional; unused in v1) {action, params} in → arbitrary JSON out

Health rules the server applies: transport error or 5xxdown; 2xxok; anything else → degraded. An explicit {"status":"ok|degraded|down","detail":"…"} body overrides the status-code heuristic. Bodies are size-limited (health 64 KiB, manifest 1 MiB).

Minimal example — a Go plugin service

package main

import (
    "encoding/json"
    "net/http"
)

func main() {
    http.HandleFunc("/manifest", func(w http.ResponseWriter, r *http.Request) {
        json.NewEncoder(w).Encode(map[string]any{
            "provider":     "ACME Cloud",
            "version":      "2.1.0",
            "authType":     "apikey",
            "capabilities": []map[string]any{
                {"id": "widgets.list", "method": "GET", "endpoint": "/widgets", "description": "List widgets."},
            }, // a plain []string{"widgets.list"} is also accepted
            "configFields": []map[string]any{
                {"key": "apiKey", "label": "API key", "type": "password", "required": true, "secret": true},
            },
        })
    })
    http.HandleFunc("/health", func(w http.ResponseWriter, r *http.Request) {
        json.NewEncoder(w).Encode(map[string]any{"status": "ok", "detail": "acme cloud reachable"})
    })
    http.HandleFunc("/invoke", func(w http.ResponseWriter, r *http.Request) {
        var in struct {
            Action string          `json:"action"`
            Params json.RawMessage `json:"params"`
        }
        json.NewDecoder(r.Body).Decode(&in)
        json.NewEncoder(w).Encode(map[string]any{"ok": true, "action": in.Action})
    })
    http.ListenAndServe(":9100", nil)
}

Register it

From the panel's Plugins card → Register external plugin (name + base URL), or via the API:

curl -X POST http://localhost:8080/api/admin/plugins \
  -H "Authorization: $SUPERADMIN_TOKEN" -H "Content-Type: application/json" \
  -d '{"name":"acme-cloud","baseURL":"http://127.0.0.1:9100","provider":"ACME Cloud"}'

It starts disabled; enable it and run a health check from the panel. Because it runs as its own process/container, an external plugin is also the sandboxing path for less-trusted integrations.


Lifecycle, config & secrets

  • Enable/disable and config persist to PocketBase: the app_settings record keyed global, in its pluginSettings field. That is the top (L1) layer of the integration cascade, stored the same way the org (L2) and user (L3) layers are. Enabling calls Init; disabling calls Shutdown.
  • Before the settings have been read — a cold database, or a service account still to be configured — every /api/admin/plugins* endpoint answers 503 and no write is accepted. The server never treats an unreachable database as "no plugins configured", so an outage cannot quietly erase the settings; it retries in the background until the read succeeds.
  • Upgrading from a pre-PocketBase install: an existing plugins.json (see PLUGINS_FILE) is imported into the database on the first boot that finds no settings there, and renamed to plugins.json.migrated.
  • Secrets (Secret: true fields) are returned masked. On save, a field still equal to the mask keeps its stored value; send a new value to change it, or an empty string to clear it.
  • Required fields are validated when enabling — enabling fails with a clear error if one is blank.
  • If Init fails (e.g. bad credentials), the state is still saved and the API returns the plugin plus a warning; fix the config and re-save.

Managing plugins (superadmin API)

All endpoints require a superadmin bearer token (Authorization: <token> from POST /api/auth/login). See the panel's Management API reference too.

Method Path Body Purpose
GET /api/admin/plugins list all plugins + state + last health
GET /api/admin/plugins/{name} one plugin
PUT /api/admin/plugins/{name} {enabled?, config?} enable/disable + configure
POST /api/admin/plugins {name, baseURL, provider?} register an external plugin
DELETE /api/admin/plugins/{name} remove an external plugin (built-ins only disable)
POST /api/admin/plugins/{name}/health run a health check now

Testing your plugin

  1. Build + restart (built-in) or start your service (external) and register it.
  2. GET /api/admin/plugins → confirm your descriptor, config fields, capabilities.
  3. PUT /api/admin/plugins/{name} {"enabled":true, "config":{…}} → enable with config.
  4. POST /api/admin/plugins/{name}/health → confirm the live probe classifies correctly.
  5. Restart the server → confirm state reloads from PocketBase.

A Go unit test can exercise a built-in directly:

p := &acme.Plugin{}
_ = p.Init(context.Background(), map[string]string{"apiKey": "test"})
if h := p.HealthCheck(context.Background()); h.Status == "" {
    t.Fatal("expected a health status")
}

Not yet implemented (roadmap)

The contract is shaped for these; see doc.go:

  • Generic invocation API — an endpoint to call any plugin's Invoke from a client, with a normalized request/response envelope. The purpose-built callers exist (Manager.InvokeWith / InvokeBatchWith, driven by the integration routes and internal/api/vehicleproviders.go); what is missing is the generic route.
  • Resilience — retry/backoff, circuit breaker, per-plugin latency/error metrics.
  • Per-tenant credentials for arbitrary plugins — the two built-in connectors already have them, through the hand-written /api/integrations/toyota and /api/integrations/anker-solix routes and their superadmin → org admin → user config cascade. What is missing is the generic version: per-org/per-user config keyed off ConfigFields, so a newly registered plugin gets the same treatment without new endpoints.
  • Audit logging of plugin access. (Charger control commands are already audited to the control_audit collection; this is the wider plugin case.)

Until the generic invocation API lands, Invoke is reachable only through the purpose-built routes: the two integrations' own endpoints, and the vehicle-provider layer that builds a car from a manufacturer account and feeds the car's provider tab (see internal/api/vehicleproviders.go).