Log Lua Reference Documentation
chilkat.Log
Current Version: 11.7.0
Markdown version of this page for AI tools (v 11.7.0) · all AI docs
Chilkat.Log
Use
Add informational messages, error messages, and tagged text values to
explain what the application is doing.
Log integers, 64-bit integers, timestamps, and date/time values when
tracing state changes or timing-sensitive workflows.
Record binary data as Base64, hex, or shortened previews so byte-level
values can be inspected safely in text logs.
Compute and log hashes of data when comparing content, verifying
transformations, or avoiding full data dumps.
Clear the log and continue building new diagnostic output during
repeated operations or test runs.
For an extended overview, see
Log Class Overview.
Build readable structured diagnostic logs with nested context and tagged values.
Chilkat.Log is a lightweight structured logging helper for
creating readable diagnostic logs from application code. It can record nested
operation contexts, informational messages, error messages, timestamps,
integers, 64-bit integers, tagged values, binary data, Base64 data, hex data,
shortened data previews, and computed hashes. It is useful when code needs a
clear step-by-step record of operations, inputs, outputs, and diagnostic
values for troubleshooting.
Nested operation context
EnterContext and LeaveContext to group log
entries under readable operation names.
Messages and errors
Numbers and timestamps
Binary diagnostics
Hash logging
Clear and reuse
Log object, enter a named context for the operation,
log the important values and decisions as the code runs, leave the context,
and inspect the resulting text if troubleshooting is needed. Use
Chilkat.Log for application-level diagnostic output; use
LastErrorText on Chilkat objects for detailed diagnostics from
Chilkat method calls.
Object Creation
local chilkat = require("chilkat")
local log = chilkat.Log.new()Creates the object (chilkat.Log() does the same). Lua's garbage collector frees it when it is no longer referenced; log:dispose() frees it at once, and in Lua 5.4 and later local log <close> = chilkat.Log.new() frees it when the block ends. Calling a method of a disposed object raises an error.
Errors
A method that fails returns nil followed by the error text, as io.open does: local body, err = log:method(...), where err is the object's last_error_text. Wrap the call in assert() to raise an error with that text instead. Methods that answer a question return true or false, numbers are returned as they are (check last_method_success where the description says a value means failure), and property reads and writes never fail for Chilkat reasons.
Misuse raises a Lua error: a wrong argument type or a missing argument (bad argument #1 to ...), an unknown property name, a write to a read-only property, an out-of-range integer, or an object of the wrong class.
Names are Chilkat's in snake_case: QuickGetStr is quick_get_str, LastErrorText is last_error_text. Properties are fields (log.verbose_logging = true) and methods use the colon (log:method(...)). Strings are UTF-8; binary data is a Lua string of bytes. Indexes are 0-based, as in every Chilkat API. Unlocking: call chilkat.unlock_bundle("...") once at startup.
Properties
DebugLogFilePath
local strVal = log.debug_log_file_path
log.debug_log_file_path = strVal
If set to a file path, this property logs the LastErrorText of each Chilkat method or property call to the specified file. This logging helps identify the context and history of Chilkat calls leading up to any crash or hang, aiding in debugging.
Enabling the VerboseLogging property provides more detailed information. This property is mainly used for debugging rare instances where a Chilkat method call causes a hang or crash, which should generally not happen.
Possible causes of hangs include:
- A timeout property set to 0, indicating an infinite timeout.
- A hang occurring within an event callback in the application code.
- An internal bug in the Chilkat code causing the hang.
LastErrorHtml
local strVal = log.last_error_html
Provides HTML-formatted information about the last called method or property. If a method call fails or behaves unexpectedly, check this property for details. Note that information is available regardless of the method call's success.
topLastErrorText
local strVal = log.last_error_text
Provides plain text information about the last called method or property. If a method call fails or behaves unexpectedly, check this property for details. Note that information is available regardless of the method call's success.
LastErrorXml
local strVal = log.last_error_xml
Provides XML-formatted information about the last called method or property. If a method call fails or behaves unexpectedly, check this property for details. Note that information is available regardless of the method call's success.
topLastMethodSuccess
local boolVal = log.last_method_success
log.last_method_success = boolVal
Indicates the success or failure of the most recent method call: true means success, false means failure. This property remains unchanged by property setters or getters. This method is present to address challenges in checking for null or Nothing returns in certain programming languages. Note: This property does not apply to methods that return integer values or to boolean-returning methods where the boolean does not indicate success or failure.
VerboseLogging
local boolVal = log.verbose_logging
log.verbose_logging = boolVal
If set to true, then the contents of LastErrorText (or LastErrorXml, or LastErrorHtml) may contain more verbose information. The default value is false. Verbose logging should only be used for debugging. The potentially large quantity of logged information may adversely affect peformance.
Version
local strVal = log.version
Methods
Clear
log:clear(initial_tag)
Clears all existing log entries and starts a new log whose top-level context is named initialTag.
Log* methods. The completed structured log can be inspected through the Log object's diagnostic text, such as LastErrorText.EnterContext
log:enter_context(tag)
Begins a nested logging context named tag. Entries written after this call are grouped inside the new context until a matching LeaveContext is called.
EnterContext with LeaveContext. Contexts may be nested to reflect operation hierarchy.LeaveContext
Ends the current nested logging context and returns logging to its parent context.
LogData
-- message is a string
log:log_data(tag, message)
Adds a tagged text value to the current context. The output associates tag with message, making this useful for named values such as filenames, paths, IDs, states, or protocol fields.
LogDataBase64_2
-- byte_data is a string of bytes
log:log_data_base64_2(tag, byte_data)
Encodes szByteData bytes beginning at pByteData as Base64 and logs the result under tag.
LogDataHex2
-- byte_data is a string of bytes
log:log_data_hex2(tag, byte_data)
Encodes szByteData bytes beginning at pByteData as hexadecimal text and logs the result under tag.
szByteData readable bytes.LogDataMax
-- message is a string
-- max_num_chars is an integer
log:log_data_max(tag, message, max_num_chars)
Adds a tagged text value to the current context, but limits the logged value to at most the first maxNumChars characters of message.
LogDateTime
-- gmt is a boolean
log:log_date_time(tag, gmt)
Logs the current date and time under tag using an RFC 822-style date/time representation. If gmt is true, the logged time is GMT/UTC; otherwise local system time is used.
LogDateTime for a calendar date with timezone context. Use LogTimestamp for a time-of-day marker.LogError
log:log_error(message)
Adds message as an error entry in the current logging context.
LastErrorText produced by other Chilkat objects when their operations fail.LogHash2
-- hash_alg is a string
-- byte_data is a string of bytes
log:log_hash2(tag, hash_alg, byte_data)
Computes a hash of szByteData bytes beginning at pByteData and logs the digest as hexadecimal text under tag. Supported values for hashAlg are SHA1, SHA256, SHA384, SHA512, and MD5.
MD5 and SHA1 are not suitable when cryptographic collision resistance is required. Prefer SHA-256 or stronger for security-sensitive hashing.LogInfo
log:log_info(message)
Adds message as an informational entry in the current logging context.
LogData when the entry is better represented as a named value.LogInt
-- value is an integer
log:log_int(tag, value)
Adds the integer value to the current log under tag.
LogInt64
-- value is an integer
log:log_int64(tag, value)
Adds the signed 64-bit integer value to the current log under tag.
LogTimestamp
log:log_timestamp(tag)
Logs the current time-of-day under tag in HH:MM:SS:mmm form, where mmm represents milliseconds.