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Pulse 1.0.1: Nine Lanes for the Plugins the App Already Registered

#maui #observability #apppulse #nuvyntralabs

A field app fails in the yard and the log is a wall of framework noise. The useful line is the one the app already raised: captive portal, a failed job, a sync conflict.

Pulse shows those lines in a nine-lane table while the session is still running. Version 1.0.1 ships as two packages at the same version. The host listens. The CLI draws.

This post is the walkthrough: UseMauiPulse(), maui-pulse attach, and how to read a quiet row.

What Pulse is

Plugin.Maui.Pulse is a Debug sink inside the MAUI app. UseMauiPulse() finds allow-listed plugins that are already in dependency injection, stays subscribed to their events, and POSTs JSON to the development machine.

Plugin.Maui.Pulse.Cli is the global tool. maui-pulse attach listens on port 7878 and draws the table. The person using the app does not tap anything for Pulse.
Host Plugin.Maui.Pulse 1.0.1
CLI Plugin.Maui.Pulse.Cli 1.0.1
Command maui-pulse attach
Endpoint http://127.0.0.1:7878/ (emulator: 10.0.2.2)
Source github.com/nuvyntralabs/MauiPulse
Docs nuvyntralabs.github.io/toolkits/maui-pulse/

Pulse does not scrape logcat, Charles, Firebase, Sentry, or MAUI Connectivity. Unknown sources are dropped. It does not start a plugin, and it does not invent a row from the operating system when a package is missing.

Register the host

Add the host package to the app. Install the CLI on the machine. Do not add Plugin.Maui.Pulse.Cli as a PackageReference.

dotnet add package Plugin.Maui.Pulse --version 1.0.1
dotnet tool install -g Plugin.Maui.Pulse.Cli --source https://api.nuget.org/v3/index.json
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builder
    .UseMauiApp<App>()
    .UseMauiPulse();
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UseMauiPulse() only registers services. After Build(), the initializer resolves the package name (AppInfo.PackageName unless you set Package), opens the sink, walks the allow-list, and subscribes to instances already in DI. A plugin registered after that pass is missed.

Release builds set Enabled to false before your callback. Set options.Enabled = true only when you intend the sink to run in Release. A closed CLI does not crash the host: the POST times out in 3 seconds and the error is swallowed.

The app still registers the plugins it already uses. Pulse only listens.

Attach

USB Android needs a reverse before the phone can reach the CLI:

adb reverse tcp:7878 tcp:7878
maui-pulse attach --package com.myapp.android --android --port 7878
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iOS:

maui-pulse attach --package com.myapp.ios --ios --port 7878
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Every session command requires --package (one Android application id or one iOS bundle id). attach and listen also require --android or --ios. JSON for a different package is dropped. Two apps need two Pulse windows.

maui-pulse 1.0.1  attach  com.myapp.android  android  :7878
session 8f2a

NETWORK   Plugin.Maui.NetworkMonitor      captive portal
API       Plugin.Maui.NetworkDiagnostics  —
QUEUE     Plugin.Maui.JobQueue            visits#184
          Plugin.Maui.RetryQueue          — not installed
SYNC      Plugin.Maui.OfflineSync         conflict on Visit
PERMS     Plugin.Maui.PermissionFlow      —
HEALTH    Plugin.Maui.AppHealth           battery 18%
LEAK      Plugin.Maui.LeakAnalyser        —
CRASH     Plugin.Maui.Diagnostics         —
SESSION   Plugin.Maui.DeviceSession       session 8f2a
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Row Meaning
A headline (captive portal, visits#184) At least one allow-listed event arrived
— Subscribed, waiting. This is not a failure
— not installed The assembly is not loaded
— not registered The package is referenced and UseX() / AddX() was not called

--lanes network,sync,queue hides rows. It does not add plugins to the allow-list. GeoLocator, PushRouter, SmartUpload, and every other package are never a lane.

The nine lanes, and the registration Pulse looks for:

Lane Package Register
NETWORK NetworkMonitor AddNetworkMonitor
API NetworkDiagnostics UseNetworkDiagnostics
QUEUE JobQueue, and RetryQueue on its own row UseMauiJobQueue, UseMauiRetryQueue
SYNC OfflineSync UseOfflineSync
PERMS PermissionFlow UsePermissionFlow
HEALTH AppHealth UseAppHealth
LEAK LeakAnalyser UseLeakAnalyser
CRASH Diagnostics UseMauiDiagnostics
SESSION DeviceSession UseDeviceSession

QUEUE is two plugins. JobQueue alone is a valid session. RetryQueue then shows — not installed.

After the session

maui-pulse listen is the same HTTP sink with no table. GET / returns { "ok": true, "tool": "maui-pulse" }. --stdin accepts one JSON payload for a test or an agent.

Live events are optional for the file lanes. Copy the known files off the device, then inspect them. pull copies from a folder you already have. --adb only prints how to copy. It does not scrape logcat, and logcat.txt in that folder is ignored.

maui-pulse pull --package com.myapp.android --from ./device-files --out ./pulled
maui-pulse queues --package com.myapp.android --from ./pulled
maui-pulse sync --package com.myapp.android --from ./pulled
maui-pulse incident --package com.myapp.android --from ./pulled --out incident.zip
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Known names: plugin.maui.jobqueue.db3, plugin.maui.retryqueue.db3, offlinesync.db3, and maui-diagnostics/. queues and sync are read-only. They do not drain a queue or retry a row. incident zips the allow-listed files plus manifest.json.

Exit 0 includes skipped lanes and missing queue files. Exit 1 means no allow-listed evidence or the port bind failed. Exit 2 is usage.

On an interactive terminal the CLI asks every 4 hours whether to update from nuget.org. Skip it with --no-update-check or NUVYNTRA_NO_UPDATE_CHECK=1. CI, --format json, and piped output skip the prompt. The CLI does not phone home.

When something looks wrong

What you see What to do
Every lane is — not installed Those packages are not in this app. Pulse will not fill the lane from the OS.
— not registered The assembly loaded. Call the plugin's UseX() before the app finishes starting.
The table stays empty and the phone is on USB Run adb reverse tcp:7878 tcp:7878 again after unplug.
A plugin you added at runtime never appears Bind runs once at startup. Register it in MauiProgram.
Release is silent Enabled is false unless you set options.Enabled = true.
Sentry or logcat lines never show up They are dropped. Pulse renders the nine lanes only.

Plugin.Maui.Observability can POST at the same port. It is a pipe, not a tenth lane. Domains other than Network, Health, Sync, and Session are dropped.

Where Pulse sits next to the other tools

Need Tool
What the allow-listed plugins are doing in this Debug session Pulse
SDK, workloads, and the csproj maui-dev doctor
Startup and page traces Plugin.Maui.Performance / maui-perf
An exporter the app owns Plugin.Maui.Observability

adb logcat, Charles, Firebase Performance, and Sentry remain the tools for raw logs, HTTP, and a report that arrives after the session. Pulse is the table for the plugins you already registered.

Try it 

dotnet add package Plugin.Maui.Pulse --version 1.0.1
dotnet tool install -g Plugin.Maui.Pulse.Cli --source https://api.nuget.org/v3/index.json
adb reverse tcp:7878 tcp:7878
maui-pulse attach --package com.myapp.android --android --port 7878
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Call UseMauiPulse(), keep the UseX() lines you already have, and read a — as waiting.

By Niladri

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