|
| 1 | +# Signals Framework |
| 2 | + |
| 3 | +A language-agnostic framework for defining, processing, and visualizing observability signals across multiple data sources and dashboard systems. |
| 4 | + |
| 5 | +## Overview |
| 6 | + |
| 7 | +The signals framework provides a standardized way to define observability metrics (signals) that can be processed into dashboard visualizations. It supports multiple data sources (Prometheus, Loki, OTEL) and can generate dashboards for various visualization systems. |
| 8 | + |
| 9 | +## Language-Agnostic Interface Specifications |
| 10 | + |
| 11 | +To ensure consistent implementation across all target languages, the framework provides formal interface specifications: |
| 12 | + |
| 13 | +### 1. Method Interface Specification (`signal_methods.md`) |
| 14 | + |
| 15 | +Defines the exact methods that must be implemented for the Signal class/object in every language: |
| 16 | + |
| 17 | +- **Builder Methods**: `withTopK()`, `withExprWrappersMixin()`, `withOffset()`, etc. |
| 18 | +- **Panel Rendering**: `asTimeSeries()`, `asStat()`, `asGauge()`, `asTable()`, etc. |
| 19 | +- **Panel Composition**: `asPanelMixin()`, `asTarget()`, `asTableColumn()`, etc. |
| 20 | +- **Expression Generation**: `asPanelExpression()`, `asRuleExpression()` |
| 21 | +- **Utilities**: `getVariablesMultiChoice()` |
| 22 | + |
| 23 | +### 2. OpenAPI Interface (`signal_interface.yaml`) |
| 24 | + |
| 25 | +REST API specification that can be used to: |
| 26 | +- Generate client stubs for each language |
| 27 | +- Validate method signatures and data structures |
| 28 | +- Ensure consistent input/output contracts |
| 29 | + |
| 30 | +### 3. Core Schema (`signal.cue`, `signal_source.cue`) |
| 31 | + |
| 32 | +CUE schema definitions that provide: |
| 33 | +- Type-safe signal and signal group definitions |
| 34 | +- Validation rules for all signal properties |
| 35 | +- Data structure contracts for cross-language compatibility |
| 36 | + |
| 37 | +## Implementation Strategy |
| 38 | + |
| 39 | +### Language-Specific Implementation |
| 40 | + |
| 41 | +Each target language must implement the Signal interface following these guidelines: |
| 42 | + |
| 43 | +**Jsonnet** (Reference Implementation) |
| 44 | +```jsonnet |
| 45 | +local signals = signal.init(config); |
| 46 | +signals.mySignal.withTopK(10).asTimeSeries() |
| 47 | +``` |
| 48 | + |
| 49 | +**TypeScript** |
| 50 | +```typescript |
| 51 | +const signal = new Signal(config); |
| 52 | +signal.withTopK(10).asTimeSeries(); |
| 53 | +``` |
| 54 | + |
| 55 | +**Python** |
| 56 | +```python |
| 57 | +signal = Signal(config) |
| 58 | +signal.with_top_k(10).as_time_series() |
| 59 | +``` |
| 60 | + |
| 61 | +**Go** |
| 62 | +```go |
| 63 | +panel := signal.WithTopK(10).AsTimeSeries() |
| 64 | +``` |
| 65 | + |
| 66 | +### Consistency Requirements |
| 67 | + |
| 68 | +All implementations must: |
| 69 | + |
| 70 | +1. **Method Signatures**: Match the interface specification exactly |
| 71 | +2. **Expression Transformation**: Follow the same auto-transformation rules |
| 72 | +3. **Template Expansion**: Support identical variable templates |
| 73 | +4. **Panel Structure**: Generate compatible Grafana panel objects |
| 74 | +5. **Testing**: Include comprehensive test suites |
| 75 | + |
| 76 | +## Core Functions |
| 77 | + |
| 78 | +The framework implements these core functions consistently across languages: |
| 79 | + |
| 80 | +### 1. Signal Definition & Validation |
| 81 | +``` |
| 82 | +Input: Signal configuration (JSON/YAML/Code) |
| 83 | +Output: Validated Signal object with transformation rules |
| 84 | +``` |
| 85 | + |
| 86 | +### 2. Expression Processing |
| 87 | +``` |
| 88 | +Input: Signal + context (datasource, aggregation level) |
| 89 | +Output: PromQL/LogQL expressions with auto-transformations |
| 90 | +``` |
| 91 | + |
| 92 | +### 3. Panel Generation |
| 93 | +``` |
| 94 | +Input: Signal + panel type |
| 95 | +Output: Complete Grafana panel configuration |
| 96 | +``` |
| 97 | + |
| 98 | +### 4. Dashboard Assembly |
| 99 | +``` |
| 100 | +Input: Signal collection + metadata |
| 101 | +Output: Complete dashboard with panels and variables |
| 102 | +``` |
| 103 | + |
| 104 | +## Expression Transformation Rules |
| 105 | + |
| 106 | +All implementations follow these automatic transformations: |
| 107 | + |
| 108 | +- **Counter**: `rate(metric[interval])` or similar range functions |
| 109 | +- **Histogram**: `histogram_quantile(0.95, rate(metric[interval])) by (le)` |
| 110 | +- **Gauge/Info/Raw**: No transformation |
| 111 | +- **Aggregation**: `sum by (labels) (expression)` when aggregation is enabled |
| 112 | + |
| 113 | +## Supported Languages |
| 114 | + |
| 115 | +- ✅ **Jsonnet** - Reference implementation (common-lib) |
| 116 | +- 🔄 **TypeScript** - Web/Node.js environments |
| 117 | +- 🔄 **Python** - Data science and automation |
| 118 | +- 🔄 **Go** - Performance-critical applications |
| 119 | + |
| 120 | +## Schema Definitions |
| 121 | + |
| 122 | +- **`signal.cue`** - Core signal and signal group schema with validation |
| 123 | +- **`signal_source.cue`** - Data source-specific configuration schema |
| 124 | +- **`signal_interface.yaml`** - OpenAPI specification for method contracts |
| 125 | +- **`signal_methods.md`** - Detailed method interface documentation |
| 126 | + |
| 127 | +## Getting Started |
| 128 | + |
| 129 | +### 1. Define Signals |
| 130 | +Create signal definitions using the CUE schema: |
| 131 | +```jsonnet |
| 132 | +{ |
| 133 | + name: "CPU Usage", |
| 134 | + type: "gauge", |
| 135 | + unit: "percent", |
| 136 | + sources: { |
| 137 | + prometheus: { |
| 138 | + expr: "100 - avg(rate(cpu_idle[5m])) * 100" |
| 139 | + } |
| 140 | + } |
| 141 | +} |
| 142 | +``` |
| 143 | + |
| 144 | +### 2. Validate Definitions |
| 145 | +```bash |
| 146 | +make test # Validates against CUE schema |
| 147 | +``` |
| 148 | + |
| 149 | +### 3. Implement Language Bindings |
| 150 | +Use the interface specifications to implement Signal classes in your target language: |
| 151 | + |
| 152 | +- Follow `signal_methods.md` for method signatures |
| 153 | +- Use `signal_interface.yaml` for code generation |
| 154 | +- Implement expression transformation rules |
| 155 | +- Add comprehensive tests |
| 156 | + |
| 157 | +### 4. Generate Dashboards |
| 158 | +```typescript |
| 159 | +const signal = new Signal(config); |
| 160 | +const dashboard = new Dashboard() |
| 161 | + .addPanel(signal.asTimeSeries()) |
| 162 | + .addVariables(Signal.getVariablesMultiChoice([signal])); |
| 163 | +``` |
| 164 | + |
| 165 | +## File Structure |
| 166 | + |
| 167 | +``` |
| 168 | +signals/ |
| 169 | +├── schema/ |
| 170 | +│ ├── signal.cue # Core schema definitions |
| 171 | +│ ├── signal_source.cue # Source-specific schema |
| 172 | +│ ├── signal_interface.yaml # OpenAPI method contracts |
| 173 | +│ ├── signal_methods.md # Method interface spec |
| 174 | +│ └── tests/ # Validation test files |
| 175 | +├── gen/ # Generated code output |
| 176 | +├── architecture.md # Architecture documentation |
| 177 | +├── requirements.md # Functional requirements |
| 178 | +└── README.md # This file |
| 179 | +``` |
| 180 | + |
| 181 | +## Development Workflow |
| 182 | + |
| 183 | +1. **Schema First**: Define/modify schemas in CUE files |
| 184 | +2. **Validate**: Ensure test files pass validation |
| 185 | +3. **Interface**: Update method specifications if needed |
| 186 | +4. **Implement**: Code language-specific implementations |
| 187 | +5. **Test**: Verify cross-language compatibility |
| 188 | +6. **Generate**: Use for dashboard/alert generation |
| 189 | + |
| 190 | +This approach ensures that regardless of the implementation language, all Signal objects behave consistently and generate compatible dashboard outputs. |
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