Support @amrc-factoryplus/sparkplug-app. (#7)

* Fetch device addresses from the Directory.
* Fetch full service records from the Directory.
* Provide a Command Escalation service interface.

lib/service-client.js

@@ -8,6 +8,7 @@ import { Debug } from "./debug.js";
 import { Service } from "./uuids.js";
 
 import Auth from "./service/auth.js";
+import CmdEsc from "./service/cmdesc.js";
 import ConfigDB from "./service/configdb.js";
 import Directory from "./service/directory.js";
 import Discovery from "./service/discovery.js";
@@ -73,6 +74,7 @@ export class ServiceClient {
  * mostly be defined only on the service interface. */
 ServiceClient.define_interfaces(
     ["Auth", Auth, `check_acl fetch_acl resolve_principal`],
+    ["CmdEsc", CmdEsc, ``],
     ["ConfigDB", ConfigDB, `fetch_configdb:get_config`],
     ["Directory", Directory, ``],
     ["Discovery", Discovery,

lib/service/cmdesc.js

@@ -0,0 +1,38 @@
+/*
+ * Factory+ NodeJS Utilities
+ * Command Escalation service interface.
+ * Copyright 2023 AMRC.
+ */
+
+import { Address } from "../sparkplug/util.js";
+import { Service } from "../uuids.js";
+
+import { ServiceInterface } from "./service-interface.js";
+
+export default class CmdEsc extends ServiceInterface {
+    constructor (fplus) {
+        super(fplus);
+        this.service = Service.Command_Escalation;
+        this.log = this.debug.log.bind(this.debug, "cmdesc");
+    }
+
+    async request_cmd ({ address, name, type, value }) {
+        const [st] = await this.fetch({
+            method:     "POST",
+            url:        `v1/address/${address}`,
+            body:       { name, type, value },
+        });
+        if (st != 200)
+            this.throw(`Can't set metric ${name} of ${address}`, st);
+    }
+
+    async rebirth (address) {
+        const ctrl = address.isDevice() ? "Device Control" : "Node Control";
+        await this.request_cmd({
+            address:    address,
+            name:       `${ctrl}/Rebirth`,
+            type:       "Boolean",
+            value:      true,
+        });
+    }
+}

lib/service/directory.js

@@ -4,6 +4,7 @@
  * Copyright 2023 AMRC.
  */
 
+import { Address } from "../sparkplug/util.js";
 import { Service, Null as Null_UUID } from "../uuids.js";
 
 import { ServiceInterface } from "./service-interface.js";
@@ -14,17 +15,33 @@ export default class Directory extends ServiceInterface {
         this.service = Service.Directory;
         this.log = this.debug.log.bind(this.debug, "directory");
     }
-    
-    async get_service_urls (service) {
+
+    async get_service_info (service) {
         const [st, specs] = await this.fetch(`/v1/service/${service}`);
         if (st == 404) {
             this.log("Can't find service %s: %s", service, st);
             return;
         }
         if (st != 200)
             this.throw(`Can't get service records for ${service}`, st);
+        if (!Array.isArray(specs))
+            this.throw(`Invalid service response for ${service}`);
+        if (specs.length > 1)
+            this.throw(`More than one service record for ${service}`);
 
-        return specs.map(s => s.url).filter(u => u != null);
+        return specs[0];
+    }
+
+    async get_service_url (service) {
+        const spec = await this.get_service_info(service);
+        return spec?.url;
+    }
+
+    /* XXX Endpoint for compatibility. This will only ever return a
+     * single result. */
+    async get_service_urls (service) {
+        const url = await this.get_service_url(service);
+        return url ? [url] : undefined;
     }
 
     async register_service_url (service, url) {
@@ -37,4 +54,18 @@ export default class Directory extends ServiceInterface {
             this.throw(`Can't register service ${service}`, st);
         this.log("Registered %s for %s", url, service);
     }
+
+    async get_device_info (device) {
+        const [st, info] = await this.fetch(`v1/device/${device}`);
+        if (st == 404) return;
+        if (st != 200)
+            this.throw(`Can't find device ${device}`, st);
+        return info;
+    }
+
+    async get_device_address (device) {
+        const info = await this.get_device_info(device);
+        if (!info) return;
+        return new Address(info.group_id, info.node_id, info.device_id);
+    }
 }

lib/service/discovery.js

@@ -41,6 +41,8 @@ export default class Discovery extends ServiceInterface {
         return this.fplus.Directory.get_service_urls(service);
     }
 
+    /* This interface is deprecated. The concept of 'multiple providers
+     * for a service' was never properly implemented. */
     async service_urls (service) {
         this.debug.log("service", `[${service}] Looking for URL...`);
         if (this.urls.has(service)) {
@@ -60,9 +62,6 @@ export default class Discovery extends ServiceInterface {
         }
     }
 
-    /* XXX This interface is deprecated. Services may have multiple
-     * URLs, and we cannot do liveness testing here as we don't know all
-     * the protocols. */
     async service_url (service) {
         const urls = await this.service_urls(service);
         return urls?.[0];