| // Copyright 2015 The Vanadium Authors. All rights reserved. |
| // Use of this source code is governed by a BSD-style |
| // license that can be found in the LICENSE file. |
| |
| // Package vlog implements a general-purpose logging system. It is modeled on |
| // glog; the differences from glog are: |
| // |
| // - interfaces are used to allow for multiple implementations and instances. |
| // In particular, application and runtime logging can be separated. |
| // We also expect to stream log messages to external log collectors rather |
| // to local storage. |
| // |
| // - the Warn family of methods are not provided; their main use |
| // is to avoid the flush that's implicit in the Error routines |
| // rather than any semantic difference between warnings and errors. |
| // |
| // - Info logging and Event logging is separated with the former expected |
| // to be somewhat spammy and the latter to be used sparingly. |
| // |
| // - Event logging includes methods for unconditionally (i.e. regardless |
| // of any command line options) logging the current goroutine's stack |
| // or the stacks of all goroutines. |
| // |
| // - The use of interfaces and encapsulated state means that a single |
| // function (V) can no longer be used for 'if guarded' and 'chained' logging. |
| // That is: |
| // if vlog.V(1) { ... } and vlog.V(1).Infof( ... ) |
| // becomes |
| // if logger.V(1) { ... } and logger.VI(1).Infof( ... ) |
| // |
| // vlog also creates a global instance of the Logger (vlog.Log) and |
| // provides command line flags (see flags.go). Parsing of these flags is |
| // performed by calling one of ConfigureLibraryLoggerFromFlags or |
| // ConfigureLoggerFromFlags . |
| // |
| // The supported flags are: |
| // |
| // -logtostderr=false |
| // Logs are written to standard error instead of to files. |
| // -alsologtostderr=false |
| // Logs are written to standard error as well as to files. |
| // -stderrthreshold=ERROR |
| // Log events at or above this severity are logged to standard |
| // error as well as to files. |
| // -log_dir="" |
| // Log files will be written to this directory instead of the |
| // default temporary directory. |
| // |
| // Other flags provide aids to debugging: |
| // |
| // -log_backtrace_at="" |
| // When set to a file and line number holding a logging statement, |
| // such as |
| // -log_backtrace_at=gopherflakes.go:234 |
| // a stack trace will be written to the Info log whenever execution |
| // hits that statement. (Unlike with -vmodule, the ".go" must be |
| // present.) |
| // -v=0 |
| // Enable V-leveled logging at the specified level. |
| // -vmodule="" |
| // The syntax of the argument is a comma-separated list of pattern=N, |
| // where pattern is a literal file name (minus the ".go" suffix) or |
| // "glob" pattern and N is a V level. For instance, |
| // -vmodule=gopher*=3 |
| // sets the V level to 3 in all Go files whose names begin "gopher". |
| // -max_stack_buf_size=<size in bytes> |
| // Set the max size (bytes) of the byte buffer to use for stack |
| // traces. The default max is 4M; use powers of 2 since the |
| // stack size will be grown exponentially until it exceeds the max. |
| // A min of 128K is enforced and any attempts to reduce this will |
| // be silently ignored. |
| // |
| package vlog |
