Mobile Session Replay: SDK Recording parameters and API

[bruno-garcia]

This ticket defines some aspects of recording a mobile app and supporting data/context to send to Sentry: It serves to track what parameters we will need and to align between iOS and Android.

Recording parameters and Options

These parameters/options might not be public, but we'll use these to control or adjust video quality, size and recording overhead.

Let's not put this into SentryOptions directly, but create a new nested object SessionReplayOptions which contains all of these params. SentryOptions then holds a ref to this nested object (sentryOptions.setSessionReplayOptions(replayOptions)).

Public options:

• sessionReplay.sessionSampleRate: float - sample rate
• sessionReplay.errorSampleRate: float - If the entire session is not sampled, use the sample rate to sample sessions when an error occurs.
• quality: high|medium|low - for later, predefined quality options that change bitrate, resolution, maybe mimeType under the hood

Masking:

We'll redact all text input controls, WebView, labels, images (except when loaded from the bundle), custom controls by default.

• [ ] Provide a way to pause/resume recording for certain screens (E.g. a PIN-code screen we cannot really redact properly). It should probably be a top-level API of the static class (Sentry.resumeSessionReplay/Sentry.pauseSessionReplay)
  • [ ] Let's bring this up with frontend/backend, because there will be gaps between replay segments. Maybe we could add new RREvent types or breadcrumbs indicating the replay was paused/resumed to surface this in the frontend.
• [ ] Provide a way to redact views based on their class name. We should do that on SDK init - register a list of classes that you know are sensitive from the beginning. sessionReplayOptions.addClassForMasking(), name TBD
• [ ] Provide a way to redact specific view instances. Via an extension property/function on iOS and Kotlin Android, e.g. sampleView.sentryBlock = true|false
  • [ ] On Android we could also use view.setTag("sentry-block|unblock").
  • [ ] In case of Java, extension property wouldn't work so we probably need to call to Sentry static class, maybe let's not do it in the first version

Internal/Private Recording options:

• frameRate: float: Screenshot every N seconds, default is 1, 0.5 is a valid option
• bitRate: int: The quality of the 'video', defaults to 20.
• ~mimeType: enum: h264~ - let's always hardcode it to h264
• ~height: Used on Android. The height of the video. Width adjusts proportionally. Default 720. This might depend on device it runs.~
• scaling: Used on iOS and Android. Default 1x that means,for an iPhone 15 Pro, the video is 320x840

[brustolin]

Update for iOS:

Public options

• [x] sessionSampleRate: float
• [x] errorSampleRate: float
• [x] quality: high|medium|low
• [x] redactAllText
• [x] redactAllImages

Internal/Private Recording options

• [x] frameRate
• [x] bitRate
• [x] scaling

and a few extra internal options to change behaviour

• [x] errorReplayDuration = 30s
• [x] sessionSegmentDuration = 5s
• [x] maximumDuration = 1h