log

Logging functions for debugging and troubleshooting. The log namespace provides functions to print messages at different severity levels (info, warning, error) to the console. Messages include timestamps and the current bar index for easy reference during backtesting.

Quick Example 

from pynecore.lib import log, close, high, ta, bar_index, script

@script.indicator(title="Debug Indicator", overlay=True)
def main():
    sma20: float = ta.sma(close, 20)
    
    if bar_index % 10 == 0:
        log.info("Bar {0}: close={1}, sma20={2}", bar_index, close, sma20)
    
    if close > high:
        log.warning("Invalid data at bar {0}", bar_index)
    
    if sma20 < 0:
        log.error("Unexpected negative SMA: {0}", sma20)

Functions

info()

Logs an informational message to the console.

ParameterTypeDescription
formatStringstrFormat string with {0}, {1}, etc. placeholders
*argsAnyValues to substitute into the format string

Returns: None

Example:

log.info("Signal at bar {0}: price={1}", bar_index, close)

warning()

Logs a warning message to the console.

ParameterTypeDescription
formatStringstrFormat string with {0}, {1}, etc. placeholders
*argsAnyValues to substitute into the format string

Returns: None

Example:

log.warning("Price spike detected: {0}", high)

error()

Logs an error message to the console.

ParameterTypeDescription
formatStringstrFormat string with {0}, {1}, etc. placeholders
*argsAnyValues to substitute into the format string

Returns: None

Example:

log.error("Calculation error: {0}", error_value)

Behavior in Security Contexts

Log calls inside request.security() processes are suppressed by default, matching TradingView behavior. To redirect security process logs to a file, set the PYNE_SECURITY_LOG environment variable:

PYNE_SECURITY_LOG=security.log pyne run script.py data --security "1D=data_1D"

Each log line in the file is prefixed with the context identifier ([SYMBOL TIMEFRAME]):

[AAPL 1D] [2025-07-05 14:30:00-0400] bar:    42 INFO    SMA value: 150.25

See Debugging Security Contexts for details.

Compatibility

All logging functions are fully implemented. Format strings use 0-indexed placeholders ({0}, {1}, etc.) similar to Python’s str.format() method. Timestamps are adjusted to match the script’s timezone, and the current bar index is automatically included in log output for easier debugging during backtests.