refactor: consolidate SDK Watchable with generic map/eq and rename call to fetch

sdk/base/lib/util/GetContainerIp.ts

@@ -12,7 +12,7 @@ export class GetContainerIp extends Watchable<string> {
     super(effects)
   }
 
-  protected call(callback?: () => void) {
+  protected fetch(callback?: () => void) {
     return this.effects.getContainerIp({ ...this.opts, callback })
   }
 }

sdk/base/lib/util/GetHostInfo.ts

@@ -12,7 +12,7 @@ export class GetHostInfo extends Watchable<Host | null> {
     super(effects)
   }
 
-  protected call(callback?: () => void) {
+  protected fetch(callback?: () => void) {
     return this.effects.getHostInfo({ ...this.opts, callback })
   }
 }

sdk/base/lib/util/GetOutboundGateway.ts

@@ -8,7 +8,7 @@ export class GetOutboundGateway extends Watchable<string> {
     super(effects)
   }
 
-  protected call(callback?: () => void) {
+  protected fetch(callback?: () => void) {
     return this.effects.getOutboundGateway({ callback })
   }
 }

sdk/base/lib/util/GetServiceManifest.ts

@@ -1,18 +1,47 @@
 import { Effects } from '../Effects'
 import { Manifest, PackageId } from '../osBindings'
+import { deepEqual } from './deepEqual'
 import { Watchable } from './Watchable'
 
-export class GetServiceManifest extends Watchable<Manifest> {
+export class GetServiceManifest<
+  Mapped = Manifest | null,
+> extends Watchable<Manifest | null, Mapped> {
   protected readonly label = 'GetServiceManifest'
 
   constructor(
     effects: Effects,
     readonly opts: { packageId: PackageId },
+    options?: {
+      map?: (value: Manifest | null) => Mapped
+      eq?: (a: Mapped, b: Mapped) => boolean
+    },
   ) {
-    super(effects)
+    super(effects, options)
   }
 
-  protected call(callback?: () => void) {
+  protected fetch(callback?: () => void) {
     return this.effects.getServiceManifest({ ...this.opts, callback })
   }
 }
+
+export function getServiceManifest(
+  effects: Effects,
+  packageId: PackageId,
+): GetServiceManifest<Manifest | null>
+export function getServiceManifest<Mapped>(
+  effects: Effects,
+  packageId: PackageId,
+  map: (manifest: Manifest | null) => Mapped,
+  eq?: (a: Mapped, b: Mapped) => boolean,
+): GetServiceManifest<Mapped>
+export function getServiceManifest<Mapped>(
+  effects: Effects,
+  packageId: PackageId,
+  map?: (manifest: Manifest | null) => Mapped,
+  eq?: (a: Mapped, b: Mapped) => boolean,
+): GetServiceManifest<Mapped> {
+  return new GetServiceManifest<Mapped>(effects, { packageId }, {
+    map: map ?? ((a) => a as Mapped),
+    eq: eq ?? ((a, b) => deepEqual(a, b)),
+  })
+}

sdk/base/lib/util/GetSslCertificate.ts

@@ -14,7 +14,7 @@ export class GetSslCertificate extends Watchable<[string, string, string]> {
     super(effects)
   }
 
-  protected call(callback?: () => void) {
+  protected fetch(callback?: () => void) {
     return this.effects.getSslCertificate({ ...this.opts, callback })
   }
 }

sdk/base/lib/util/GetStatus.ts

@@ -12,7 +12,7 @@ export class GetStatus extends Watchable<StatusInfo | null> {
     super(effects)
   }
 
-  protected call(callback?: () => void) {
+  protected fetch(callback?: () => void) {
     return this.effects.getStatus({ ...this.opts, callback })
   }
 }

sdk/base/lib/util/GetSystemSmtp.ts

@@ -9,7 +9,7 @@ export class GetSystemSmtp extends Watchable<T.SmtpValue | null> {
     super(effects)
   }
 
-  protected call(callback?: () => void) {
+  protected fetch(callback?: () => void) {
     return this.effects.getSystemSmtp({ callback })
   }
 }

sdk/base/lib/util/Watchable.ts

@@ -1,55 +1,124 @@
 import { Effects } from '../Effects'
 import { AbortedError } from './AbortedError'
+import { deepEqual } from './deepEqual'
 import { DropGenerator, DropPromise } from './Drop'
 
-export abstract class Watchable<T> {
-  constructor(readonly effects: Effects) {}
+export abstract class Watchable<Raw, Mapped = Raw> {
+  protected readonly mapFn: (value: Raw) => Mapped
+  protected readonly eqFn: (a: Mapped, b: Mapped) => boolean
 
-  protected abstract call(callback?: () => void): Promise<T>
+  constructor(
+    readonly effects: Effects,
+    options?: {
+      map?: (value: Raw) => Mapped
+      eq?: (a: Mapped, b: Mapped) => boolean
+    },
+  ) {
+    this.mapFn = options?.map ?? ((a) => a as unknown as Mapped)
+    this.eqFn = options?.eq ?? ((a, b) => deepEqual(a, b))
+  }
+
+  /**
+   * Fetch the current value, optionally registering a callback for change notification.
+   * The callback should be invoked when the underlying data changes.
+   */
+  protected abstract fetch(callback?: () => void): Promise<Raw>
   protected abstract readonly label: string
 
   /**
-   * Returns the value. Reruns the context from which it has been called if the underlying value changes
+   * Produce a stream of raw values. Default implementation uses fetch() with
+   * effects callback in a loop. Override for custom subscription mechanisms
+   * (e.g. fs.watch).
    */
-  const(): Promise<T> {
-    return this.call(
-      this.effects.constRetry &&
-        (() => this.effects.constRetry && this.effects.constRetry()),
-    )
-  }
-
-  /**
-   * Returns the value. Does nothing if the value changes
-   */
-  once(): Promise<T> {
-    return this.call()
-  }
-
-  private async *watchGen(abort?: AbortSignal) {
+  protected async *produce(abort: AbortSignal): AsyncGenerator<Raw, void> {
     const resolveCell = { resolve: () => {} }
     this.effects.onLeaveContext(() => {
       resolveCell.resolve()
     })
-    abort?.addEventListener('abort', () => resolveCell.resolve())
-    while (this.effects.isInContext && !abort?.aborted) {
+    abort.addEventListener('abort', () => resolveCell.resolve())
+    while (this.effects.isInContext && !abort.aborted) {
       let callback: () => void = () => {}
       const waitForNext = new Promise<void>((resolve) => {
         callback = resolve
         resolveCell.resolve = resolve
       })
-      yield await this.call(() => callback())
+      yield await this.fetch(() => callback())
       await waitForNext
     }
-    return new Promise<never>((_, rej) => rej(new AbortedError()))
+  }
+
+  /**
+   * Lifecycle hook called when const() registers a subscription.
+   * Return a cleanup function to be called when the subscription ends.
+   * Override for side effects like FileHelper's consts tracking.
+   */
+  protected onConstRegistered(_value: Mapped): (() => void) | void {}
+
+  /**
+   * Internal generator that maps raw values and deduplicates using eq.
+   */
+  private async *watchGen(
+    abort: AbortSignal,
+  ): AsyncGenerator<Mapped, void, unknown> {
+    let prev: { value: Mapped } | null = null
+    for await (const raw of this.produce(abort)) {
+      if (abort.aborted) return
+      const mapped = this.mapFn(raw)
+      if (!prev || !this.eqFn(prev.value, mapped)) {
+        prev = { value: mapped }
+        yield mapped
+      }
+    }
+  }
+
+  /**
+   * Returns the value. Reruns the context from which it has been called if the underlying value changes
+   */
+  async const(): Promise<Mapped> {
+    const abort = new AbortController()
+    const gen = this.watchGen(abort.signal)
+    const res = await gen.next()
+    const value = res.value as Mapped
+    if (this.effects.constRetry) {
+      const constRetry = this.effects.constRetry
+      const cleanup = this.onConstRegistered(value)
+      gen.next().then(
+        () => {
+          abort.abort()
+          cleanup?.()
+          constRetry()
+        },
+        () => {
+          abort.abort()
+          cleanup?.()
+        },
+      )
+    } else {
+      abort.abort()
+    }
+    return value
+  }
+
+  /**
+   * Returns the value. Does nothing if the value changes
+   */
+  async once(): Promise<Mapped> {
+    return this.mapFn(await this.fetch())
   }
 
   /**
    * Watches the value. Returns an async iterator that yields whenever the value changes
    */
-  watch(abort?: AbortSignal): AsyncGenerator<T, never, unknown> {
+  watch(abort?: AbortSignal): AsyncGenerator<Mapped, never, unknown> {
     const ctrl = new AbortController()
     abort?.addEventListener('abort', () => ctrl.abort())
-    return DropGenerator.of(this.watchGen(ctrl.signal), () => ctrl.abort())
+    return DropGenerator.of(
+      (async function* (gen): AsyncGenerator<Mapped, never, unknown> {
+        yield* gen
+        throw new AbortedError()
+      })(this.watchGen(ctrl.signal)),
+      () => ctrl.abort(),
+    )
   }
 
   /**
@@ -57,13 +126,13 @@ export abstract class Watchable<T> {
    */
   onChange(
     callback: (
-      value: T | undefined,
+      value: Mapped | undefined,
       error?: Error,
     ) => { cancel: boolean } | Promise<{ cancel: boolean }>,
   ) {
     ;(async () => {
       const ctrl = new AbortController()
-      for await (const value of this.watch(ctrl.signal)) {
+      for await (const value of this.watchGen(ctrl.signal)) {
         try {
           const res = await callback(value)
           if (res.cancel) {
@@ -90,7 +159,7 @@ export abstract class Watchable<T> {
   /**
    * Watches the value. Returns when the predicate is true
    */
-  waitFor(pred: (value: T) => boolean): Promise<T> {
+  waitFor(pred: (value: Mapped) => boolean): Promise<Mapped> {
     const ctrl = new AbortController()
     return DropPromise.of(
       Promise.resolve().then(async () => {

sdk/base/lib/util/getServiceInterface.ts

@@ -8,11 +8,10 @@ import {
   HostnameInfo,
 } from '../types'
 import { Effects } from '../Effects'
-import { AbortedError } from './AbortedError'
-import { DropGenerator, DropPromise } from './Drop'
 import { IpAddress, IPV6_LINK_LOCAL } from './ip'
 import { deepEqual } from './deepEqual'
 import { once } from './once'
+import { Watchable } from './Watchable'
 
 export type UrlString = string
 export type HostId = string
@@ -440,136 +439,29 @@ const makeInterfaceFilled = async ({
   return interfaceFilled
 }
 
-export class GetServiceInterface<Mapped = ServiceInterfaceFilled | null> {
+export class GetServiceInterface<
+  Mapped = ServiceInterfaceFilled | null,
+> extends Watchable<ServiceInterfaceFilled | null, Mapped> {
+  protected readonly label = 'GetServiceInterface'
+
   constructor(
-    readonly effects: Effects,
+    effects: Effects,
     readonly opts: { id: string; packageId?: string },
-    readonly map: (interfaces: ServiceInterfaceFilled | null) => Mapped,
-    readonly eq: (a: Mapped, b: Mapped) => boolean,
-  ) {}
-
-  /**
-   * Returns the requested service interface. Reruns the context from which it has been called if the underlying value changes
-   */
-  async const() {
-    let abort = new AbortController()
-    const watch = this.watch(abort.signal)
-    const res = await watch.next()
-    if (this.effects.constRetry) {
-      watch
-        .next()
-        .then(() => {
-          abort.abort()
-          this.effects.constRetry && this.effects.constRetry()
-        })
-        .catch()
-    }
-    return res.value
-  }
-  /**
-   * Returns the requested service interface. Does nothing if the value changes
-   */
-  async once() {
-    const { id, packageId } = this.opts
-    const interfaceFilled = await makeInterfaceFilled({
-      effects: this.effects,
-      id,
-      packageId,
-    })
-
-    return this.map(interfaceFilled)
-  }
-
-  private async *watchGen(abort?: AbortSignal) {
-    let prev = null as { value: Mapped } | null
-    const { id, packageId } = this.opts
-    const resolveCell = { resolve: () => {} }
-    this.effects.onLeaveContext(() => {
-      resolveCell.resolve()
-    })
-    abort?.addEventListener('abort', () => resolveCell.resolve())
-    while (this.effects.isInContext && !abort?.aborted) {
-      let callback: () => void = () => {}
-      const waitForNext = new Promise<void>((resolve) => {
-        callback = resolve
-        resolveCell.resolve = resolve
-      })
-      const next = this.map(
-        await makeInterfaceFilled({
-          effects: this.effects,
-          id,
-          packageId,
-          callback,
-        }),
-      )
-      if (!prev || !this.eq(prev.value, next)) {
-        yield next
-      }
-      await waitForNext
-    }
-    return new Promise<never>((_, rej) => rej(new AbortedError()))
-  }
-
-  /**
-   * Watches the requested service interface. Returns an async iterator that yields whenever the value changes
-   */
-  watch(abort?: AbortSignal): AsyncGenerator<Mapped, never, unknown> {
-    const ctrl = new AbortController()
-    abort?.addEventListener('abort', () => ctrl.abort())
-    return DropGenerator.of(this.watchGen(ctrl.signal), () => ctrl.abort())
-  }
-
-  /**
-   * Watches the requested service interface. Takes a custom callback function to run whenever the value changes
-   */
-  onChange(
-    callback: (
-      value: Mapped | null,
-      error?: Error,
-    ) => { cancel: boolean } | Promise<{ cancel: boolean }>,
+    options?: {
+      map?: (value: ServiceInterfaceFilled | null) => Mapped
+      eq?: (a: Mapped, b: Mapped) => boolean
+    },
   ) {
-    ;(async () => {
-      const ctrl = new AbortController()
-      for await (const value of this.watch(ctrl.signal)) {
-        try {
-          const res = await callback(value)
-          if (res.cancel) {
-            ctrl.abort()
-            break
-          }
-        } catch (e) {
-          console.error(
-            'callback function threw an error @ GetServiceInterface.onChange',
-            e,
-          )
-        }
-      }
-    })()
-      .catch((e) => callback(null, e))
-      .catch((e) =>
-        console.error(
-          'callback function threw an error @ GetServiceInterface.onChange',
-          e,
-        ),
-      )
+    super(effects, options)
   }
 
-  /**
-   * Watches the requested service interface. Returns when the predicate is true
-   */
-  waitFor(pred: (value: Mapped) => boolean): Promise<Mapped> {
-    const ctrl = new AbortController()
-    return DropPromise.of(
-      Promise.resolve().then(async () => {
-        for await (const next of this.watchGen(ctrl.signal)) {
-          if (pred(next)) {
-            return next
-          }
-        }
-        throw new Error('context left before predicate passed')
-      }),
-      () => ctrl.abort(),
-    )
+  protected fetch(callback?: () => void) {
+    return makeInterfaceFilled({
+      effects: this.effects,
+      id: this.opts.id,
+      packageId: this.opts.packageId,
+      callback,
+    })
   }
 }
 
@@ -589,12 +481,10 @@ export function getOwnServiceInterface<Mapped>(
   map?: (interfaces: ServiceInterfaceFilled | null) => Mapped,
   eq?: (a: Mapped, b: Mapped) => boolean,
 ): GetServiceInterface<Mapped> {
-  return new GetServiceInterface(
-    effects,
-    { id },
-    map ?? ((a) => a as Mapped),
-    eq ?? ((a, b) => deepEqual(a, b)),
-  )
+  return new GetServiceInterface<Mapped>(effects, { id }, {
+    map: map ?? ((a) => a as Mapped),
+    eq: eq ?? ((a, b) => deepEqual(a, b)),
+  })
 }
 
 export function getServiceInterface(
@@ -613,10 +503,8 @@ export function getServiceInterface<Mapped>(
   map?: (interfaces: ServiceInterfaceFilled | null) => Mapped,
   eq?: (a: Mapped, b: Mapped) => boolean,
 ): GetServiceInterface<Mapped> {
-  return new GetServiceInterface(
-    effects,
-    opts,
-    map ?? ((a) => a as Mapped),
-    eq ?? ((a, b) => deepEqual(a, b)),
-  )
+  return new GetServiceInterface<Mapped>(effects, opts, {
+    map: map ?? ((a) => a as Mapped),
+    eq: eq ?? ((a, b) => deepEqual(a, b)),
+  })
 }

sdk/base/lib/util/getServiceInterfaces.ts

@@ -1,9 +1,8 @@
 import { Effects } from '../Effects'
 import { PackageId } from '../osBindings'
-import { AbortedError } from './AbortedError'
 import { deepEqual } from './deepEqual'
-import { DropGenerator, DropPromise } from './Drop'
 import { ServiceInterfaceFilled, filledAddress } from './getServiceInterface'
+import { Watchable } from './Watchable'
 
 const makeManyInterfaceFilled = async ({
   effects,
@@ -40,139 +39,34 @@ const makeManyInterfaceFilled = async ({
   return serviceInterfacesFilled
 }
 
-export class GetServiceInterfaces<Mapped = ServiceInterfaceFilled[]> {
+export class GetServiceInterfaces<
+  Mapped = ServiceInterfaceFilled[],
+> extends Watchable<ServiceInterfaceFilled[], Mapped> {
+  protected readonly label = 'GetServiceInterfaces'
+
   constructor(
-    readonly effects: Effects,
+    effects: Effects,
     readonly opts: { packageId?: string },
-    readonly map: (interfaces: ServiceInterfaceFilled[]) => Mapped,
-    readonly eq: (a: Mapped, b: Mapped) => boolean,
-  ) {}
-
-  /**
-   * Returns the service interfaces for the package. Reruns the context from which it has been called if the underlying value changes
-   */
-  async const() {
-    let abort = new AbortController()
-    const watch = this.watch(abort.signal)
-    const res = await watch.next()
-    if (this.effects.constRetry) {
-      watch
-        .next()
-        .then(() => {
-          abort.abort()
-          this.effects.constRetry && this.effects.constRetry()
-        })
-        .catch()
-    }
-    return res.value
-  }
-  /**
-   * Returns the service interfaces for the package. Does nothing if the value changes
-   */
-  async once() {
-    const { packageId } = this.opts
-    const interfaceFilled: ServiceInterfaceFilled[] =
-      await makeManyInterfaceFilled({
-        effects: this.effects,
-        packageId,
-      })
-
-    return this.map(interfaceFilled)
-  }
-
-  private async *watchGen(abort?: AbortSignal) {
-    let prev = null as { value: Mapped } | null
-    const { packageId } = this.opts
-    const resolveCell = { resolve: () => {} }
-    this.effects.onLeaveContext(() => {
-      resolveCell.resolve()
-    })
-    abort?.addEventListener('abort', () => resolveCell.resolve())
-    while (this.effects.isInContext && !abort?.aborted) {
-      let callback: () => void = () => {}
-      const waitForNext = new Promise<void>((resolve) => {
-        callback = resolve
-        resolveCell.resolve = resolve
-      })
-      const next = this.map(
-        await makeManyInterfaceFilled({
-          effects: this.effects,
-          packageId,
-          callback,
-        }),
-      )
-      if (!prev || !this.eq(prev.value, next)) {
-        yield next
-      }
-      await waitForNext
-    }
-    return new Promise<never>((_, rej) => rej(new AbortedError()))
-  }
-
-  /**
-   * Watches the service interfaces for the package. Returns an async iterator that yields whenever the value changes
-   */
-  watch(abort?: AbortSignal): AsyncGenerator<Mapped, never, unknown> {
-    const ctrl = new AbortController()
-    abort?.addEventListener('abort', () => ctrl.abort())
-    return DropGenerator.of(this.watchGen(ctrl.signal), () => ctrl.abort())
-  }
-
-  /**
-   * Watches the service interfaces for the package. Takes a custom callback function to run whenever the value changes
-   */
-  onChange(
-    callback: (
-      value: Mapped | null,
-      error?: Error,
-    ) => { cancel: boolean } | Promise<{ cancel: boolean }>,
+    options?: {
+      map?: (value: ServiceInterfaceFilled[]) => Mapped
+      eq?: (a: Mapped, b: Mapped) => boolean
+    },
   ) {
-    ;(async () => {
-      const ctrl = new AbortController()
-      for await (const value of this.watch(ctrl.signal)) {
-        try {
-          const res = await callback(value)
-          if (res.cancel) {
-            ctrl.abort()
-            break
-          }
-        } catch (e) {
-          console.error(
-            'callback function threw an error @ GetServiceInterfaces.onChange',
-            e,
-          )
-        }
-      }
-    })()
-      .catch((e) => callback(null, e))
-      .catch((e) =>
-        console.error(
-          'callback function threw an error @ GetServiceInterfaces.onChange',
-          e,
-        ),
-      )
+    super(effects, options)
   }
 
-  /**
-   * Watches the service interfaces for the package. Returns when the predicate is true
-   */
-  waitFor(pred: (value: Mapped) => boolean): Promise<Mapped> {
-    const ctrl = new AbortController()
-    return DropPromise.of(
-      Promise.resolve().then(async () => {
-        for await (const next of this.watchGen(ctrl.signal)) {
-          if (pred(next)) {
-            return next
-          }
-        }
-        throw new Error('context left before predicate passed')
-      }),
-      () => ctrl.abort(),
-    )
+  protected fetch(callback?: () => void) {
+    return makeManyInterfaceFilled({
+      effects: this.effects,
+      packageId: this.opts.packageId,
+      callback,
+    })
   }
 }
 
-export function getOwnServiceInterfaces(effects: Effects): GetServiceInterfaces
+export function getOwnServiceInterfaces(
+  effects: Effects,
+): GetServiceInterfaces
 export function getOwnServiceInterfaces<Mapped>(
   effects: Effects,
   map: (interfaces: ServiceInterfaceFilled[]) => Mapped,
@@ -183,12 +77,10 @@ export function getOwnServiceInterfaces<Mapped>(
   map?: (interfaces: ServiceInterfaceFilled[]) => Mapped,
   eq?: (a: Mapped, b: Mapped) => boolean,
 ): GetServiceInterfaces<Mapped> {
-  return new GetServiceInterfaces(
-    effects,
-    {},
-    map ?? ((a) => a as Mapped),
-    eq ?? ((a, b) => deepEqual(a, b)),
-  )
+  return new GetServiceInterfaces<Mapped>(effects, {}, {
+    map: map ?? ((a) => a as Mapped),
+    eq: eq ?? ((a, b) => deepEqual(a, b)),
+  })
 }
 
 export function getServiceInterfaces(
@@ -207,10 +99,8 @@ export function getServiceInterfaces<Mapped>(
   map?: (interfaces: ServiceInterfaceFilled[]) => Mapped,
   eq?: (a: Mapped, b: Mapped) => boolean,
 ): GetServiceInterfaces<Mapped> {
-  return new GetServiceInterfaces(
-    effects,
-    opts,
-    map ?? ((a) => a as Mapped),
-    eq ?? ((a, b) => deepEqual(a, b)),
-  )
+  return new GetServiceInterfaces<Mapped>(effects, opts, {
+    map: map ?? ((a) => a as Mapped),
+    eq: eq ?? ((a, b) => deepEqual(a, b)),
+  })
 }

sdk/base/lib/util/index.ts

@@ -19,7 +19,7 @@ export { Watchable } from './Watchable'
 export { GetContainerIp } from './GetContainerIp'
 export { GetHostInfo } from './GetHostInfo'
 export { GetOutboundGateway } from './GetOutboundGateway'
-export { GetServiceManifest } from './GetServiceManifest'
+export { GetServiceManifest, getServiceManifest } from './GetServiceManifest'
 export { GetSslCertificate } from './GetSslCertificate'
 export { GetStatus } from './GetStatus'
 export { GetSystemSmtp } from './GetSystemSmtp'

sdk/package/lib/StartSdk.ts

@@ -59,7 +59,8 @@ import {
   setupOnInit,
   setupOnUninit,
 } from '../../base/lib/inits'
-import { DropGenerator } from '../../base/lib/util/Drop'
+import { GetContainerIp } from '../../base/lib/util/GetContainerIp'
+import { GetStatus } from '../../base/lib/util/GetStatus'
 import {
   getOwnServiceInterface,
   ServiceInterfaceFilled,
@@ -257,90 +258,7 @@ export class StartSdk<Manifest extends T.SDKManifest> {
           Parameters<T.Effects['getContainerIp']>[0],
           'callback'
         > = {},
-      ) => {
-        async function* watch(abort?: AbortSignal) {
-          const resolveCell = { resolve: () => {} }
-          effects.onLeaveContext(() => {
-            resolveCell.resolve()
-          })
-          abort?.addEventListener('abort', () => resolveCell.resolve())
-          while (effects.isInContext && !abort?.aborted) {
-            let callback: () => void = () => {}
-            const waitForNext = new Promise<void>((resolve) => {
-              callback = resolve
-              resolveCell.resolve = resolve
-            })
-            yield await effects.getContainerIp({ ...options, callback })
-            await waitForNext
-          }
-        }
-        return {
-          const: () =>
-            effects.getContainerIp({
-              ...options,
-              callback:
-                effects.constRetry &&
-                (() => effects.constRetry && effects.constRetry()),
-            }),
-          once: () => effects.getContainerIp(options),
-          watch: (abort?: AbortSignal) => {
-            const ctrl = new AbortController()
-            abort?.addEventListener('abort', () => ctrl.abort())
-            return DropGenerator.of(watch(ctrl.signal), () => ctrl.abort())
-          },
-          onChange: (
-            callback: (
-              value: string | null,
-              error?: Error,
-            ) => { cancel: boolean } | Promise<{ cancel: boolean }>,
-          ) => {
-            ;(async () => {
-              const ctrl = new AbortController()
-              for await (const value of watch(ctrl.signal)) {
-                try {
-                  const res = await callback(value)
-                  if (res.cancel) {
-                    ctrl.abort()
-                    break
-                  }
-                } catch (e) {
-                  console.error(
-                    'callback function threw an error @ getContainerIp.onChange',
-                    e,
-                  )
-                }
-              }
-            })()
-              .catch((e) => callback(null, e))
-              .catch((e) =>
-                console.error(
-                  'callback function threw an error @ getContainerIp.onChange',
-                  e,
-                ),
-              )
-          },
-          waitFor: async (pred: (value: string | null) => boolean) => {
-            const resolveCell = { resolve: () => {} }
-            effects.onLeaveContext(() => {
-              resolveCell.resolve()
-            })
-            while (effects.isInContext) {
-              let callback: () => void = () => {}
-              const waitForNext = new Promise<void>((resolve) => {
-                callback = resolve
-                resolveCell.resolve = resolve
-              })
-              const res = await effects.getContainerIp({ ...options, callback })
-              if (pred(res)) {
-                resolveCell.resolve()
-                return res
-              }
-              await waitForNext
-            }
-            return null
-          },
-        }
-      },
+      ) => new GetContainerIp(effects, options),
 
       /**
        * Get the service's current status with reactive subscription support.
@@ -355,90 +273,7 @@ export class StartSdk<Manifest extends T.SDKManifest> {
       getStatus: (
         effects: T.Effects,
         options: Omit<Parameters<T.Effects['getStatus']>[0], 'callback'> = {},
-      ) => {
-        async function* watch(abort?: AbortSignal) {
-          const resolveCell = { resolve: () => {} }
-          effects.onLeaveContext(() => {
-            resolveCell.resolve()
-          })
-          abort?.addEventListener('abort', () => resolveCell.resolve())
-          while (effects.isInContext && !abort?.aborted) {
-            let callback: () => void = () => {}
-            const waitForNext = new Promise<void>((resolve) => {
-              callback = resolve
-              resolveCell.resolve = resolve
-            })
-            yield await effects.getStatus({ ...options, callback })
-            await waitForNext
-          }
-        }
-        return {
-          const: () =>
-            effects.getStatus({
-              ...options,
-              callback:
-                effects.constRetry &&
-                (() => effects.constRetry && effects.constRetry()),
-            }),
-          once: () => effects.getStatus(options),
-          watch: (abort?: AbortSignal) => {
-            const ctrl = new AbortController()
-            abort?.addEventListener('abort', () => ctrl.abort())
-            return DropGenerator.of(watch(ctrl.signal), () => ctrl.abort())
-          },
-          onChange: (
-            callback: (
-              value: T.StatusInfo | null,
-              error?: Error,
-            ) => { cancel: boolean } | Promise<{ cancel: boolean }>,
-          ) => {
-            ;(async () => {
-              const ctrl = new AbortController()
-              for await (const value of watch(ctrl.signal)) {
-                try {
-                  const res = await callback(value)
-                  if (res.cancel) {
-                    ctrl.abort()
-                    break
-                  }
-                } catch (e) {
-                  console.error(
-                    'callback function threw an error @ getStatus.onChange',
-                    e,
-                  )
-                }
-              }
-            })()
-              .catch((e) => callback(null, e))
-              .catch((e) =>
-                console.error(
-                  'callback function threw an error @ getStatus.onChange',
-                  e,
-                ),
-              )
-          },
-          waitFor: async (pred: (value: T.StatusInfo | null) => boolean) => {
-            const resolveCell = { resolve: () => {} }
-            effects.onLeaveContext(() => {
-              resolveCell.resolve()
-            })
-            while (effects.isInContext) {
-              let callback: () => void = () => {}
-              const waitForNext = new Promise<void>((resolve) => {
-                callback = resolve
-                resolveCell.resolve = resolve
-              })
-              const res = await effects.getStatus({ ...options, callback })
-              if (pred(res)) {
-                resolveCell.resolve()
-                return res
-              }
-              await waitForNext
-            }
-            return null
-          },
-        }
-      },
+      ) => new GetStatus(effects, options),
 
       MultiHost: {
         /**
@@ -646,7 +481,7 @@ export class StartSdk<Manifest extends T.SDKManifest> {
         effects: E,
         hostnames: string[],
         algorithm?: T.Algorithm,
-      ) => new GetSslCertificate(effects, hostnames, algorithm),
+      ) => new GetSslCertificate(effects, { hostnames, algorithm }),
       /** Retrieve the manifest of any installed service package by its ID */
       getServiceManifest,
       healthCheck: {

sdk/package/lib/util/GetServiceManifest.ts

@@ -1,156 +0,0 @@
-import { Effects } from '../../../base/lib/Effects'
-import { Manifest, PackageId } from '../../../base/lib/osBindings'
-import { AbortedError } from '../../../base/lib/util/AbortedError'
-import { DropGenerator, DropPromise } from '../../../base/lib/util/Drop'
-import { deepEqual } from '../../../base/lib/util/deepEqual'
-
-export class GetServiceManifest<Mapped = Manifest> {
-  constructor(
-    readonly effects: Effects,
-    readonly packageId: PackageId,
-    readonly map: (manifest: Manifest | null) => Mapped,
-    readonly eq: (a: Mapped, b: Mapped) => boolean,
-  ) {}
-
-  /**
-   * Returns the manifest of a service. Reruns the context from which it has been called if the underlying value changes
-   */
-  async const() {
-    let abort = new AbortController()
-    const watch = this.watch(abort.signal)
-    const res = await watch.next()
-    if (this.effects.constRetry) {
-      watch
-        .next()
-        .then(() => {
-          abort.abort()
-          this.effects.constRetry && this.effects.constRetry()
-        })
-        .catch()
-    }
-    return res.value
-  }
-  /**
-   * Returns the manifest of a service. Does nothing if it changes
-   */
-  async once() {
-    const manifest = await this.effects.getServiceManifest({
-      packageId: this.packageId,
-    })
-    return this.map(manifest)
-  }
-
-  private async *watchGen(abort?: AbortSignal) {
-    let prev = null as { value: Mapped } | null
-    const resolveCell = { resolve: () => {} }
-    this.effects.onLeaveContext(() => {
-      resolveCell.resolve()
-    })
-    abort?.addEventListener('abort', () => resolveCell.resolve())
-    while (this.effects.isInContext && !abort?.aborted) {
-      let callback: () => void = () => {}
-      const waitForNext = new Promise<void>((resolve) => {
-        callback = resolve
-        resolveCell.resolve = resolve
-      })
-      const next = this.map(
-        await this.effects.getServiceManifest({
-          packageId: this.packageId,
-          callback: () => callback(),
-        }),
-      )
-      if (!prev || !this.eq(prev.value, next)) {
-        prev = { value: next }
-        yield next
-      }
-      await waitForNext
-    }
-    return new Promise<never>((_, rej) => rej(new AbortedError()))
-  }
-
-  /**
-   * Watches the manifest of a service. Returns an async iterator that yields whenever the value changes
-   */
-  watch(abort?: AbortSignal): AsyncGenerator<Mapped, never, unknown> {
-    const ctrl = new AbortController()
-    abort?.addEventListener('abort', () => ctrl.abort())
-    return DropGenerator.of(this.watchGen(ctrl.signal), () => ctrl.abort())
-  }
-
-  /**
-   * Watches the manifest of a service. Takes a custom callback function to run whenever it changes
-   */
-  onChange(
-    callback: (
-      value: Mapped | null,
-      error?: Error,
-    ) => { cancel: boolean } | Promise<{ cancel: boolean }>,
-  ) {
-    ;(async () => {
-      const ctrl = new AbortController()
-      for await (const value of this.watch(ctrl.signal)) {
-        try {
-          const res = await callback(value)
-          if (res.cancel) {
-            ctrl.abort()
-            break
-          }
-        } catch (e) {
-          console.error(
-            'callback function threw an error @ GetServiceManifest.onChange',
-            e,
-          )
-        }
-      }
-    })()
-      .catch((e) => callback(null, e))
-      .catch((e) =>
-        console.error(
-          'callback function threw an error @ GetServiceManifest.onChange',
-          e,
-        ),
-      )
-  }
-
-  /**
-   * Watches the manifest of a service. Returns when the predicate is true
-   */
-  waitFor(pred: (value: Mapped) => boolean): Promise<Mapped> {
-    const ctrl = new AbortController()
-    return DropPromise.of(
-      Promise.resolve().then(async () => {
-        for await (const next of this.watchGen(ctrl.signal)) {
-          if (pred(next)) {
-            return next
-          }
-        }
-        throw new Error('context left before predicate passed')
-      }),
-      () => ctrl.abort(),
-    )
-  }
-}
-
-export function getServiceManifest(
-  effects: Effects,
-  packageId: PackageId,
-): GetServiceManifest<Manifest>
-export function getServiceManifest<Mapped>(
-  effects: Effects,
-  packageId: PackageId,
-  map: (manifest: Manifest | null) => Mapped,
-  eq?: (a: Mapped, b: Mapped) => boolean,
-): GetServiceManifest<Mapped>
-export function getServiceManifest<Mapped>(
-  effects: Effects,
-  packageId: PackageId,
-  map?: (manifest: Manifest | null) => Mapped,
-  eq?: (a: Mapped, b: Mapped) => boolean,
-): GetServiceManifest<Mapped> {
-  return new GetServiceManifest(
-    effects,
-    packageId,
-    map ?? ((a) => a as Mapped),
-    eq ?? ((a, b) => deepEqual(a, b)),
-  )
-}

sdk/package/lib/util/GetSslCertificate.ts

@@ -1,122 +0,0 @@
-import { T } from '..'
-import { Effects } from '../../../base/lib/Effects'
-import { AbortedError } from '../../../base/lib/util/AbortedError'
-import { DropGenerator, DropPromise } from '../../../base/lib/util/Drop'
-
-export class GetSslCertificate {
-  constructor(
-    readonly effects: Effects,
-    readonly hostnames: string[],
-    readonly algorithm?: T.Algorithm,
-  ) {}
-
-  /**
-   * Returns the an SSL Certificate for the given hostnames if permitted. Restarts the service if it changes
-   */
-  const() {
-    return this.effects.getSslCertificate({
-      hostnames: this.hostnames,
-      algorithm: this.algorithm,
-      callback:
-        this.effects.constRetry &&
-        (() => this.effects.constRetry && this.effects.constRetry()),
-    })
-  }
-  /**
-   * Returns the an SSL Certificate for the given hostnames if permitted. Does nothing if it changes
-   */
-  once() {
-    return this.effects.getSslCertificate({
-      hostnames: this.hostnames,
-      algorithm: this.algorithm,
-    })
-  }
-
-  private async *watchGen(abort?: AbortSignal) {
-    const resolveCell = { resolve: () => {} }
-    this.effects.onLeaveContext(() => {
-      resolveCell.resolve()
-    })
-    abort?.addEventListener('abort', () => resolveCell.resolve())
-    while (this.effects.isInContext && !abort?.aborted) {
-      let callback: () => void = () => {}
-      const waitForNext = new Promise<void>((resolve) => {
-        callback = resolve
-        resolveCell.resolve = resolve
-      })
-      yield await this.effects.getSslCertificate({
-        hostnames: this.hostnames,
-        algorithm: this.algorithm,
-        callback: () => callback(),
-      })
-      await waitForNext
-    }
-    return new Promise<never>((_, rej) => rej(new AbortedError()))
-  }
-
-  /**
-   * Watches the SSL Certificate for the given hostnames if permitted. Returns an async iterator that yields whenever the value changes
-   */
-  watch(
-    abort?: AbortSignal,
-  ): AsyncGenerator<[string, string, string], never, unknown> {
-    const ctrl = new AbortController()
-    abort?.addEventListener('abort', () => ctrl.abort())
-    return DropGenerator.of(this.watchGen(ctrl.signal), () => ctrl.abort())
-  }
-
-  /**
-   * Watches the SSL Certificate for the given hostnames if permitted. Takes a custom callback function to run whenever it changes
-   */
-  onChange(
-    callback: (
-      value: [string, string, string] | null,
-      error?: Error,
-    ) => { cancel: boolean } | Promise<{ cancel: boolean }>,
-  ) {
-    ;(async () => {
-      const ctrl = new AbortController()
-      for await (const value of this.watch(ctrl.signal)) {
-        try {
-          const res = await callback(value)
-          if (res.cancel) {
-            ctrl.abort()
-            break
-          }
-        } catch (e) {
-          console.error(
-            'callback function threw an error @ GetSslCertificate.onChange',
-            e,
-          )
-        }
-      }
-    })()
-      .catch((e) => callback(null, e))
-      .catch((e) =>
-        console.error(
-          'callback function threw an error @ GetSslCertificate.onChange',
-          e,
-        ),
-      )
-  }
-
-  /**
-   * Watches the SSL Certificate for the given hostnames if permitted. Returns when the predicate is true
-   */
-  waitFor(
-    pred: (value: [string, string, string] | null) => boolean,
-  ): Promise<[string, string, string] | null> {
-    const ctrl = new AbortController()
-    return DropPromise.of(
-      Promise.resolve().then(async () => {
-        for await (const next of this.watchGen(ctrl.signal)) {
-          if (pred(next)) {
-            return next
-          }
-        }
-        return null
-      }),
-      () => ctrl.abort(),
-    )
-  }
-}

sdk/package/lib/util/fileHelper.ts

@@ -4,8 +4,8 @@ import * as TOML from '@iarna/toml'
 import * as INI from 'ini'
 import * as T from '../../../base/lib/types'
 import * as fs from 'node:fs/promises'
-import { AbortedError, asError, deepEqual } from '../../../base/lib/util'
-import { DropGenerator, DropPromise } from '../../../base/lib/util/Drop'
+import { asError, deepEqual } from '../../../base/lib/util'
+import { Watchable } from '../../../base/lib/util/Watchable'
 import { PathBase } from './Volume'
 
 const previousPath = /(.+?)\/([^/]*)$/
@@ -228,132 +228,72 @@ export class FileHelper<A> {
     return map(this.validate(data))
   }
 
-  private async readConst<B>(
+  private createFileWatchable<B>(
     effects: T.Effects,
     map: (value: A) => B,
-    eq: (left: B | null | undefined, right: B | null) => boolean,
-  ): Promise<B | null> {
-    const watch = this.readWatch(effects, map, eq)
-    const res = await watch.next()
-    if (effects.constRetry) {
-      const record: (typeof this.consts)[number] = [
-        effects.constRetry,
-        res.value,
-        map,
-        eq,
-      ]
-      this.consts.push(record)
-      watch
-        .next()
-        .then(() => {
-          this.consts = this.consts.filter((r) => r !== record)
-          effects.constRetry && effects.constRetry()
-        })
-        .catch()
-    }
-    return res.value
-  }
-
-  private async *readWatch<B>(
-    effects: T.Effects,
-    map: (value: A) => B,
-    eq: (left: B | null | undefined, right: B | null) => boolean,
-    abort?: AbortSignal,
+    eq: (left: B | null, right: B | null) => boolean,
   ) {
-    let prev: { value: B | null } | null = null
-    while (effects.isInContext && !abort?.aborted) {
-      if (await exists(this.path)) {
-        const ctrl = new AbortController()
-        abort?.addEventListener('abort', () => ctrl.abort())
-        const watch = fs.watch(this.path, {
-          persistent: false,
-          signal: ctrl.signal,
-        })
-        const newRes = await this.readOnce(map)
-        const listen = Promise.resolve()
-          .then(async () => {
-            for await (const _ of watch) {
-              ctrl.abort()
-              return null
-            }
-          })
-          .catch((e) => console.error(asError(e)))
-        if (!prev || !eq(prev.value, newRes)) {
-          console.error('yielding', JSON.stringify({ prev: prev, newRes }))
-          yield newRes
-        }
-        prev = { value: newRes }
-        await listen
-      } else {
-        yield null
-        await onCreated(this.path).catch((e) => console.error(asError(e)))
-      }
+    const doRead = async (): Promise<A | null> => {
+      const data = await this.readFile()
+      if (!data) return null
+      return this.validate(data)
     }
-    return new Promise<never>((_, rej) => rej(new AbortedError()))
-  }
+    const filePath = this.path
+    const fileHelper = this
 
-  private readOnChange<B>(
-    effects: T.Effects,
-    callback: (
-      value: B | null,
-      error?: Error,
-    ) => { cancel: boolean } | Promise<{ cancel: boolean }>,
-    map: (value: A) => B,
-    eq: (left: B | null | undefined, right: B | null) => boolean,
-  ) {
-    ;(async () => {
-      const ctrl = new AbortController()
-      for await (const value of this.readWatch(effects, map, eq, ctrl.signal)) {
-        try {
-          const res = await callback(value)
-          if (res.cancel) ctrl.abort()
-        } catch (e) {
-          console.error(
-            'callback function threw an error @ FileHelper.read.onChange',
-            e,
-          )
-        }
+    const wrappedMap = (raw: A | null): B | null => {
+      if (raw === null) return null
+      return map(raw)
+    }
+
+    return new (class extends Watchable<A | null, B | null> {
+      protected readonly label = 'FileHelper'
+
+      protected async fetch() {
+        return doRead()
       }
-    })()
-      .catch((e) => callback(null, e))
-      .catch((e) =>
-        console.error(
-          'callback function threw an error @ FileHelper.read.onChange',
-          e,
-        ),
-      )
-  }
 
-  private readWaitFor<B>(
-    effects: T.Effects,
-    pred: (value: B | null, error?: Error) => boolean,
-    map: (value: A) => B,
-  ): Promise<B | null> {
-    const ctrl = new AbortController()
-    return DropPromise.of(
-      Promise.resolve().then(async () => {
-        const watch = this.readWatch(effects, map, (_) => false, ctrl.signal)
-        while (true) {
-          try {
-            const res = await watch.next()
-            if (pred(res.value)) {
-              ctrl.abort()
-              return res.value
-            }
-            if (res.done) {
-              break
-            }
-          } catch (e) {
-            if (pred(null, e as Error)) {
-              break
-            }
+      protected async *produce(
+        abort: AbortSignal,
+      ): AsyncGenerator<A | null, void> {
+        while (this.effects.isInContext && !abort.aborted) {
+          if (await exists(filePath)) {
+            const ctrl = new AbortController()
+            abort.addEventListener('abort', () => ctrl.abort())
+            const watch = fs.watch(filePath, {
+              persistent: false,
+              signal: ctrl.signal,
+            })
+            yield await doRead()
+            await Promise.resolve()
+              .then(async () => {
+                for await (const _ of watch) {
+                  ctrl.abort()
+                  return null
+                }
+              })
+              .catch((e) => console.error(asError(e)))
+          } else {
+            yield null
+            await onCreated(filePath).catch((e) => console.error(asError(e)))
           }
         }
-        ctrl.abort()
-        return null
-      }),
-      () => ctrl.abort(),
-    )
+      }
+
+      protected onConstRegistered(value: B | null): (() => void) | void {
+        if (!this.effects.constRetry) return
+        const record: (typeof fileHelper.consts)[number] = [
+          this.effects.constRetry,
+          value,
+          wrappedMap,
+          eq,
+        ]
+        fileHelper.consts.push(record)
+        return () => {
+          fileHelper.consts = fileHelper.consts.filter((r) => r !== record)
+        }
+      }
+    })(effects, { map: wrappedMap, eq })
   }
 
   /**
@@ -372,7 +312,7 @@ export class FileHelper<A> {
   read(): ReadType<A>
   read<B>(
     map: (value: A) => B,
-    eq?: (left: B | null | undefined, right: B | null) => boolean,
+    eq?: (left: B | null, right: B | null) => boolean,
   ): ReadType<B>
   read(
     map?: (value: A) => any,
@@ -382,24 +322,19 @@ export class FileHelper<A> {
     eq = eq ?? deepEqual
     return {
       once: () => this.readOnce(map),
-      const: (effects: T.Effects) => this.readConst(effects, map, eq),
-      watch: (effects: T.Effects, abort?: AbortSignal) => {
-        const ctrl = new AbortController()
-        abort?.addEventListener('abort', () => ctrl.abort())
-        return DropGenerator.of(
-          this.readWatch(effects, map, eq, ctrl.signal),
-          () => ctrl.abort(),
-        )
-      },
+      const: (effects: T.Effects) =>
+        this.createFileWatchable(effects, map, eq).const(),
+      watch: (effects: T.Effects, abort?: AbortSignal) =>
+        this.createFileWatchable(effects, map, eq).watch(abort),
       onChange: (
         effects: T.Effects,
         callback: (
           value: A | null,
           error?: Error,
         ) => { cancel: boolean } | Promise<{ cancel: boolean }>,
-      ) => this.readOnChange(effects, callback, map, eq),
+      ) => this.createFileWatchable(effects, map, eq).onChange(callback),
       waitFor: (effects: T.Effects, pred: (value: A | null) => boolean) =>
-        this.readWaitFor(effects, pred, map),
+        this.createFileWatchable(effects, map, eq).waitFor(pred),
     }
   }
 

sdk/package/lib/util/index.ts

@@ -1,6 +1,4 @@
 export * from '../../../base/lib/util'
-export { GetSslCertificate } from './GetSslCertificate'
-export { GetServiceManifest, getServiceManifest } from './GetServiceManifest'
 
 export { Drop } from '../../../base/lib/util/Drop'
 export { Volume, Volumes } from './Volume'