fission-diagnostics
v0.10.0
Structured diagnostics and reporting primitives for Fission tools and runtime checks
Install
cargo add fission-diagnostics
Copy
Platform support
Declared by the crate author and captured when this directory was generated.
Android
Not declared
iOS
Not declared
Linux
Supported
macOS
Supported
Windows
Supported
Web
Not declared
Terminal
Not declared
Static site
Not declared
Server-rendered
Not declared
Package metadata
crates.io
View package
Documentation
Not provided
Repository
Open link
License
MIT
Latest version
0.10.0
Downloads
1925
Last updated
2026-08-02T15:07:41.200292Z
Categories
development-tools
development-tools::debugging
Keywords
debugging
diagnostics
fission
tooling
tracing
Published versions
0.10.0
0.9.2
0.9.1
0.9.0
0.8.0
0.7.0
0.6.3
0.6.2
0.6.1
0.6.0
0.5.1
0.5.0
Dependencies
Dependency metadata is not indexed yet.
README
fission-diagnostics
Structured diagnostics and telemetry for the Fission rendering pipeline.
This crate provides a global, thread-safe diagnostics system that emits structured JSON events covering every stage of the Fission frame lifecycle: diffing, layout, painting, rasterization, animation, input handling, and invariant violations. It is designed for pipeline debugging, performance profiling, and automated testing.
Architecture
The diagnostics system uses a global singleton (OnceCell<RwLock<DiagnosticsInner>>) initialized once at startup. All emission goes through the emit() function, which checks category filters and level thresholds before writing to the configured sink.
Application
|
+-- init_from_env() or init(config)
| |
| v
| DiagnosticsConfig
| +-- enabled_categories: BTreeSet<DiagCategory>
| +-- min_level: DiagLevel
| +-- sink: DiagSink
| +-- sampling: f32
|
+-- emit(category, level, event_kind)
| |
| v
| DiagnosticsInner::should_emit() -- checks category + level
| |
| v
| SinkImpl::write() -- serializes DiagEvent to JSONL
|
+-- begin_frame() / end_frame() -- frame lifecycle markers
Categories
Each diagnostic event belongs to exactly one DiagCategory:
Category | Events |
|---|---|
Frame | FrameStart, FrameEnd with per-frame statistics |
Diff | DiffSummary -- node counts for created, removed, changed nodes |
Layout | LayoutSummary -- node count, dirty count, full rebuild flag, duration |
Paint | PaintSummary, PaintNode, PaintNodeRect -- segment reuse and per-node details |
Raster | RasterSummary -- tile cache hit/miss rates |
Input | InputEvent -- pointer, keyboard, scroll, and text input events |
Animation | AnimationSummary -- active, started, replaced, ended counts |
Media | MediaSummary, MediaEvent -- video/audio node tracking |
Semantics | Reserved for accessibility tree events |
Invariants | InvariantViolation -- layout/paint consistency checks |
Test | Reserved for test harness events |
Severity levels
DiagLevel controls filtering granularity: Error \> Warn \> Info \> Debug \> Trace. The allows() method returns true when a given event level is at or above the configured minimum.
Configuration via environment variables
The init_from_env() function reads four environment variables:
Variable | Values | Default |
|---|---|---|
FISSION_DIAG | Comma-separated category names, or * for all | (empty -- nothing enabled) |
FISSION_DIAG_LEVEL | error, warn, info, debug, trace | warn |
FISSION_DIAG_SINK | stdout, file:/path/to/log.jsonl, disabled | stdout |
FISSION_DIAG_SAMPLING | Float 0.0-1.0 | 1.0 |
Example:
FISSION_DIAG=layout,paint,frame FISSION_DIAG_LEVEL=debug FISSION_DIAG_SINK=file:/tmp/fission.jsonl cargo run
Sinks
Sink | Description |
|---|---|
DiagSink::Stdout | Writes each event as a single JSON line to stdout. |
DiagSink::File(path) | Appends JSONL to the specified file. |
DiagSink::RingBuffer(cap) | Keeps the last cap events in memory (useful for in-app inspector). |
DiagSink::Disabled | Suppresses all output. |
Key types
•
DiagEvent -- The top-level event envelope. Contains schema_version (always 1), timestamp_ns, frame_no, category, level, and the event payload.
•
DiagEventKind -- Tagged enum with all concrete event payloads. Serialized with #[serde(tag = "kind", content = "payload")].
•
FrameStats -- Summary statistics attached to FrameEnd: dirty nodes, layout updates, paint hits/misses, video surfaces.
•
SnapshotProvider / SnapshotBlob -- Trait for components that can produce a JSON snapshot of their internal state (currently SnapshotKind::Layout only).
Usage
use fission_diagnostics::prelude::*;
// Initialize from environment variables
init_from_env();
// Or initialize programmatically
use fission_diagnostics::{DiagnosticsConfig, DiagSink, DiagLevel, DiagCategory};
let config = DiagnosticsConfig {
enabled_categories: [DiagCategory::Layout, DiagCategory::Paint].into_iter().collect(),
min_level: DiagLevel::Debug,
sink: DiagSink::Stdout,
sampling: 1.0,
};
fission_diagnostics::init(config);
// Emit events
begin_frame(None);
emit(DiagCategory::Layout, DiagLevel::Debug, DiagEventKind::LayoutSummary {
nodes: 1200,
dirty_count: 3,
full_rebuild: false,
duration_ns: 450_000,
});
end_frame(FrameStats::default());
Output format
Each event is a single JSON line (JSONL). Example:
{"schema_version":1,"timestamp_ns":16666667,"frame_no":1,"category":"layout","level":"debug","kind":"LayoutSummary","payload":{"nodes":1200,"dirty_count":3,"full_rebuild":false,"duration_ns":450000}}
README
fission-diagnostics
Structured diagnostics and telemetry for the Fission rendering pipeline.
This crate provides a global, thread-safe diagnostics system that emits structured JSON events covering every stage of the Fission frame lifecycle: diffing, layout, painting, rasterization, animation, input handling, and invariant violations. It is designed for pipeline debugging, performance profiling, and automated testing.
Architecture
The diagnostics system uses a global singleton (OnceCell<RwLock<DiagnosticsInner>>) initialized once at startup. All emission goes through the emit() function, which checks category filters and level thresholds before writing to the configured sink.
Application
|
+-- init_from_env() or init(config)
| |
| v
| DiagnosticsConfig
| +-- enabled_categories: BTreeSet<DiagCategory>
| +-- min_level: DiagLevel
| +-- sink: DiagSink
| +-- sampling: f32
|
+-- emit(category, level, event_kind)
| |
| v
| DiagnosticsInner::should_emit() -- checks category + level
| |
| v
| SinkImpl::write() -- serializes DiagEvent to JSONL
|
+-- begin_frame() / end_frame() -- frame lifecycle markers
Categories
Each diagnostic event belongs to exactly one DiagCategory:
Category | Events |
|---|---|
Frame | FrameStart, FrameEnd with per-frame statistics |
Diff | DiffSummary -- node counts for created, removed, changed nodes |
Layout | LayoutSummary -- node count, dirty count, full rebuild flag, duration |
Paint | PaintSummary, PaintNode, PaintNodeRect -- segment reuse and per-node details |
Raster | RasterSummary -- tile cache hit/miss rates |
Input | InputEvent -- pointer, keyboard, scroll, and text input events |
Animation | AnimationSummary -- active, started, replaced, ended counts |
Media | MediaSummary, MediaEvent -- video/audio node tracking |
Semantics | Reserved for accessibility tree events |
Invariants | InvariantViolation -- layout/paint consistency checks |
Test | Reserved for test harness events |
Severity levels
DiagLevel controls filtering granularity: Error \> Warn \> Info \> Debug \> Trace. The allows() method returns true when a given event level is at or above the configured minimum.
Configuration via environment variables
The init_from_env() function reads four environment variables:
Variable | Values | Default |
|---|---|---|
FISSION_DIAG | Comma-separated category names, or * for all | (empty -- nothing enabled) |
FISSION_DIAG_LEVEL | error, warn, info, debug, trace | warn |
FISSION_DIAG_SINK | stdout, file:/path/to/log.jsonl, disabled | stdout |
FISSION_DIAG_SAMPLING | Float 0.0-1.0 | 1.0 |
Example:
FISSION_DIAG=layout,paint,frame FISSION_DIAG_LEVEL=debug FISSION_DIAG_SINK=file:/tmp/fission.jsonl cargo run
Sinks
Sink | Description |
|---|---|
DiagSink::Stdout | Writes each event as a single JSON line to stdout. |
DiagSink::File(path) | Appends JSONL to the specified file. |
DiagSink::RingBuffer(cap) | Keeps the last cap events in memory (useful for in-app inspector). |
DiagSink::Disabled | Suppresses all output. |
Key types
•
DiagEvent -- The top-level event envelope. Contains schema_version (always 1), timestamp_ns, frame_no, category, level, and the event payload.
•
DiagEventKind -- Tagged enum with all concrete event payloads. Serialized with #[serde(tag = "kind", content = "payload")].
•
FrameStats -- Summary statistics attached to FrameEnd: dirty nodes, layout updates, paint hits/misses, video surfaces.
•
SnapshotProvider / SnapshotBlob -- Trait for components that can produce a JSON snapshot of their internal state (currently SnapshotKind::Layout only).
Usage
use fission_diagnostics::prelude::*;
// Initialize from environment variables
init_from_env();
// Or initialize programmatically
use fission_diagnostics::{DiagnosticsConfig, DiagSink, DiagLevel, DiagCategory};
let config = DiagnosticsConfig {
enabled_categories: [DiagCategory::Layout, DiagCategory::Paint].into_iter().collect(),
min_level: DiagLevel::Debug,
sink: DiagSink::Stdout,
sampling: 1.0,
};
fission_diagnostics::init(config);
// Emit events
begin_frame(None);
emit(DiagCategory::Layout, DiagLevel::Debug, DiagEventKind::LayoutSummary {
nodes: 1200,
dirty_count: 3,
full_rebuild: false,
duration_ns: 450_000,
});
end_frame(FrameStats::default());
Output format
Each event is a single JSON line (JSONL). Example:
{"schema_version":1,"timestamp_ns":16666667,"frame_no":1,"category":"layout","level":"debug","kind":"LayoutSummary","payload":{"nodes":1200,"dirty_count":3,"full_rebuild":false,"duration_ns":450000}}
Package metadata
crates.io
View package
Documentation
Not provided
Repository
Open link
License
MIT
Latest version
0.10.0
Downloads
1925
Last updated
2026-08-02T15:07:41.200292Z
Categories
development-tools
development-tools::debugging
Keywords
debugging
diagnostics
fission
tooling
tracing
Published versions
0.10.0
0.9.2
0.9.1
0.9.0
0.8.0
0.7.0
0.6.3
0.6.2
0.6.1
0.6.0
0.5.1
0.5.0
Dependencies
Dependency metadata is not indexed yet.