--- title: "Log Method/stream Definitions" description: "define logger method and output stream names" source: "https://github.com/log-10x/modules/tree/main/pipelines/compile/modules/scanner/logMethods/module.yaml" icon: "material/math-log" --- Defines function names that mark string constants as having a [log](https://doc.log10x.com/run/transform/symbol/#log) context. When parsing these invocations: ```cpp logger.error("could not connect to {}", host); cerr << "could not connect to" << host << << std::endl; ``` The string constants receive a 'log' context, unlike non-logging calls: ```js foo("could not connect to " + host); ``` Use the [symbolTypes](https://doc.log10x.com/compile/link/#symboltypes "token types read from input source/binary files written to output") argument to filter non-logging symbols and reduce library file size. ## :material-wrench-outline: Config Files To configure the Log method/stream definitions module, [:material-cog: Edit](https://doc.log10x.com/config/app/#module-config "Learn how to edit app and module configurations") these files. Below is the default configuration from: [logMethods/default.yaml](https://github.dev/log-10x/config/blob/main/pipelines/compile/scanners/logMethods/default.yaml "logMethods/default.yaml"){target="\_blank"}.
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```yaml # 🔟❎ 'compile' log methods configuration # Set the 10x pipeline to 'compile' tenx: compile # ============================ Log Options ============================= log: # 'methods' lists known method names collected from common logging # frameworks used to indicate source code logging events to stream at runtime. # Identifying those points in source code that perform logging operations # and marking them within an output symbol unit file (*.json) # allows the 'run' pipeline to correlate each TenXObject structured from the event # data back to its origin in the codebase. # To learn more about symbol contexts and their use, see https://doc.log10x.com/run/transform/symbol/#contexts methods: # Assertions are not enabled by default as they are less likely to appear in prod logs # - Assert # - assert # - assertEquals # - assertEqual - exception - Log - LOG - log - BOOST_LOG_TRIVIAL - trace - Trace - log_trace - logTrace - TRACE - LOG_TRACE - debug - Debug - logDebug - log_debug - DEBUG - LOG_DEBUG - Debugf - info - Info - log_info - logInfo - INFO - LOG_INFO - information - LogInformation - InfoF - warn - Warn - log_warn - logWarn - WARN - LOG_WARN - WarnF - warning - logWarning - LOG_WARNING - error - Error - logError - log_error - ERROR - LOG_ERROR - ErrorF - err - fatal - Fatal - log_fatal - logFatal - FATAL - LOG_FATAL - FatalF - critical - Panic # 'methodRegex' specifies an optional regex that will be applied # to a scanned source code method/function name. If matched, the method # will be considered to be a 'logging method' (see above). # For example: ^(log|Log)|(Log|log)$ methodRegex: null # 'streams' defines which source code variables within # this ANTLR syntax are treated as output streams (e.g. stdout, stderr, cerr). # Literal constants (e.g. "error connecting to {}") passed to a variable # listed below (e.g. 'cout') will be assigned a 'logger_method_invoke' # symbol source context. streams: # - assert - cout - cerr - Error - Debug - err - out - Console ``` ## :material-menu: Options Specify the options below to [configure](/config "configure") the Log method/stream definitions: |Name|Description| |---|---| |[logMethods](#logmethods "names of source code methods to mark as 'logging'")|Names of source code methods to mark as 'logging'| |[logMethodRegex](#logmethodregex "a pattern that source code methods names must match to qualify as 'logging' methods")|A pattern that source code methods names must match to qualify as 'logging' methods| |[logStreams](#logstreams "names of source code variables to mark as 'logging'")|Names of source code variables to mark as 'logging'| ### :material-menu-right-outline:**`logMethods`** Names of source code methods to mark as 'logging'. |Type|Default| |---|---| |List|\[\]| Lists 'logging' method names whose invocations to mark 'logging'. Logging frameworks commonly define standard methods to emit event information to program output (e.g., 'warn', 'error'). ### :material-menu-right-outline:**`logMethodRegex`** A pattern that source code methods names must match to qualify as 'logging' methods. |Type|Default| |---|---| |String|""| Specifies a pattern for symbol scanners to apply to source code method/function names to determine whether to mark them as 'logging'. For example: ^(log\|Log)\|(Log\|log)$. ### :material-menu-right-outline:**`logStreams`** Names of source code variables to mark as 'logging'. |Type|Default| |---|---| |List|\[\]| Lists 'logging' member names whose assignments to mark 'logging'. Programming languages commonly define standard members to emit events to output (e.g., 'out', 'cerr').
:material-github: This module is defined in [logMethods/module.yaml](https://github.com/log-10x/modules/tree/main/pipelines/compile/modules/scanner/logMethods/module.yaml "logMethods/module.yaml"){target="\_blank"}.