73 lines
4.7 KiB
Markdown
73 lines
4.7 KiB
Markdown
---
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source_files:
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- DataPRO/DbAPI/Logging/LogManager.cs
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generated_at: "2026-04-16T04:26:52.712375+00:00"
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model: "Qwen/Qwen3-Coder-Next-FP8"
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schema_version: 1
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sha256: "93d08dfeda60c1f4"
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---
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# Logging
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### **Purpose**
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This module provides centralized logging infrastructure for the `DbAPI` layer, abstracting the underlying logging mechanism (`TextLogger`) and exposing a simplified, type-safe interface for recording events with specific categories and severity levels. It ensures thread-safe initialization, enforces log level filtering, and writes all log entries to a rolling log file (`DB.log`) with standardized timestamping and formatting.
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---
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### **Public Interface**
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All members are `internal` (not `public`), per the `internal class LogManager` declaration. However, the module exposes the following static members accessible within the `DbAPI.Logging` namespace:
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- **`public static Sink DBAPILogWriter`**
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A delegate of type `Sink` (from `DTS.Common.Utilities.Logging`) assigned during initialization to the `LogMsg` method. It serves as the external-facing write endpoint for log messages.
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- **`public static void Initialize(int logSize, string path, int minLog)`**
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Initializes the logging system exactly once per application lifetime (idempotent due to early return if `_LogWriter` is non-null). Creates a `TextLogger` writing to `{path}/DB.log`, configures log rollover, sets the minimum log level (`_MinLog`), and assigns `DBAPILogWriter`.
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Parameters:
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- `logSize`: Maximum size (in bytes?) for the log file before rollover.
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- `path`: Directory path where `DB.log` will be written.
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- `minLog`: Bitwise combination of `TraceEventType` values (cast to `int`) defining the minimum severity to log (e.g., `Error | Warning`).
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- **`public static void Log(TraceEventType eventType, LogEvents logEvent, string msg)`**
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Logs a message if the `eventType` meets or exceeds the configured `_MinLog` level (via bitwise AND check). Formats the message with a timestamp, event type, `LogEvents` category, and the provided `msg`, then writes it via `LogMsg`.
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Parameters:
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- `eventType`: Severity level (e.g., `TraceEventType.Error`, `Information`).
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- `logEvent`: Category from the `LogEvents` enum.
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- `msg`: The log message text.
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- **`public static void OnWriteException(Exception ex)`**
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Callback invoked by `TextLogger` on write failures. Writes the exception message to `Console.Error`.
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---
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### **Invariants**
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- `_LogWriter` is initialized exactly once per AppDomain lifetime (enforced by `lock` + null-check in `Initialize`).
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- Log messages are written only if `(minLog & (int)eventType) == (int)eventType` holds (i.e., the event type is *included* in the configured minimum log level).
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- All log entries are prefixed with a fixed-format timestamp: `yyyy-MM-dd HH:mm:ss.fff`.
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- The log file path is always `{path}/DB.log`.
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- `_MinLog` is set during initialization and never modified afterward.
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- `DBAPILogWriter` is assigned *only* during the first call to `Initialize` and remains non-null thereafter.
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---
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### **Dependencies**
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- **Imports/Usings**:
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- `DTS.Common.Utilities.Logging` (provides `Sink`, `TextLogger`, `APILogger`).
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- `System`, `System.Diagnostics`, `System.IO`.
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- **External Types Used**:
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- `DTS.Common.Utilities.Logging.TextLogger` (core logging implementation).
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- `DTS.Common.Utilities.Logging.APILogger` (only referenced for `Sink` type via `using static`).
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- `System.TraceEventType` (severity levels).
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- **Depended Upon By**:
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- Other classes in the `DbAPI` layer (inferred from namespace `DbAPI.Logging` and `DBAPILogWriter` usage).
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- *Not* directly consumed by external consumers (all members are `internal`).
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---
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### **Gotchas**
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- **Thread Safety**: `Initialize` uses a `lock` to prevent re-initialization, but `Log` and `LogMsg` are *not* explicitly synchronized. However, `TextLogger` is assumed to be thread-safe (typical for such utilities).
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- **Silent Failures**: `LogMsg` catches and discards all exceptions during logging, potentially masking I/O errors (e.g., disk full, permission issues).
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- **Hardcoded Log Filename**: The log file is always named `DB.log`, with no configurability.
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- **Log Level Semantics**: `_MinLog` uses a bitwise mask against `TraceEventType` values. The default (`Error | Warning`) means `Information`, `Verbose`, etc., are excluded unless explicitly enabled.
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- **No Cleanup**: No `Dispose` or shutdown logic is provided; resources (e.g., file handles) persist until process termination.
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- **Timestamp Format**: Milliseconds are zero-padded to 3 digits, but no timezone info is included (local time only).
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- **Enum Naming**: `LogEvents` is poorly named (implies *events* like "Connections", but actually represents *categories* or *topics*). |