Trace support must be enabled during compilation of the SDK. Ensure that the CMake switch TRACE_ENABLED is ON, which is the SDK's default setting.
Check what TRACE_BACKEND is selected:
- stderr: This is the default backend and will print all trace infos to console using fprintf(stderr, ...).
- file: This will write the traces to the configured file.
- syslog: This will write trace to the system log using the syslog command (see man(3) syslog). This backend is for Linux and other UNIX like systems.
Check that trace is enabled at runtime. The UA application needs to enable the trace by calling trace_openlog(), which allows filtering by facility and trace level.

Our example applications offer command line switches to change the trace settings.

Listing available trace levels:

$> ./uaserverhp -l
debug levels:
  TRACE_LEVEL_DEBUG       1
  TRACE_LEVEL_DATA        2
  TRACE_LEVEL_INFO        4
  TRACE_LEVEL_FUNC_ENTER  8
  TRACE_LEVEL_FUNC_LEAVE  16
  TRACE_LEVEL_FUNC        24
  TRACE_LEVEL_NOTICE      32
  TRACE_LEVEL_WARNING     64
  TRACE_LEVEL_ERROR       128
  TRACE_LEVEL_INSANE      256
  TRACE_LEVEL_ALL         511
debug facilities:
  TRACE_FAC_PLATFORM         1
  TRACE_FAC_NETWORK          2
  TRACE_FAC_CRYPTO           4
  TRACE_FAC_IPC              8
  TRACE_FAC_BASE             16
  TRACE_FAC_MEMORY           32
  TRACE_FAC_UATCP            64
  TRACE_FAC_ENCODER          128
  TRACE_FAC_SESSION          256
  TRACE_FAC_PROVIDER         512
  TRACE_FAC_APPLICATION      1024
  TRACE_FAC_ADDRSPACE        2048
  TRACE_FAC_TIMER            4096
  TRACE_FAC_PKI              8192
  TRACE_FAC_SUBSCRIPTION     16384
  TRACE_FAC_CLIENT           32768
  TRACE_FAC_USERAPPLICATION  65536
  TRACE_FAC_FILEFORMAT       131072
  TRACE_FAC_ALL              262143
usage example: ./uaserverhp -d $((128+64+32)) -f $((1024+2048+131072))

By default, the applications only enable TRACE_LEVEL_ERROR and TRACE_LEVEL_WARNING. If you want to enable more trace levels, you can use the command line switch -d.

$> ./uaserverhp -d 255

By using the switch -f you can filter the output for the specific component e.g. TRACE_FAC_MEMORY.

$> ./uaserverhp -d 255 -f 32

Note that traces TRACE_LEVEL_ERROR ignore the facility filter and will always be shown.

File Trace

When using the file trace backend, this backend reads in its own configuration file trace.conf. This configures the trace file name, directory, and trace file rotation.

The parameters are described in the file itself.

Example trace.conf:

# The following trace settings only apply for the file-backend.
# Other trace backends will ignore these settings.
[file-trace]
# directory: Directory where the traces should be saved.
# Default is ".", which logs into the current working directory.
directory = "."
# basename: the trace file basename.
# Default is "log", which will create a name like "log.1234.1",
# by appending the process id and the sequential log file no.
basename = "log"
# log file extension
extension = ".txt"
# include the PID into the filename
include_pid = false
# Maximum number of files to create. Older files will be deleted.
max_files = 5
# Maximum number of lines per file. When this limit is reached a new file gets created.
max_lines = 1000000
# force flush after every trace line. This avoids data loss in case of a crash,
# but is much much slower.
force_flush = false
# append to existing file, overwrite when false
append = false

Adding/Removing Color from Trace Output

On Linux the stderr trace backend uses color output by default to make the trace better readable. On Windows this is disabled by default because Windows is lacking a proper terminal with color support. If you want to disable color support from the backend you can disable the CMake option ENABLE_COLOR, then the trace backend will be built without color support.

Removing Colors

When opening redirected output in primitive editors these colors might not get displayed correctly. In this case you can strip the color information (ANSI escape sequences) from the text files.

Using this Perl script you can remove the ANSI escape sequences from a file.

colorstrip.pl:

#!/usr/bin/env perl
use Term::ANSIColor qw(colorstrip);
print colorstrip(<>);

Usage:

$> cat trace.log | colorstrip.pl > trace_plain.log

Adding Colors

When you have a trace file without colors and you want to add those nice colors afterwards you can use the following little Perl script.

#!/usr/bin/env perl
use Term::ANSIColor qw(:constants);
foreach (<>) {
    local $Term::ANSIColor::AUTORESET = 1;
    if (/^E/) {
        print(BOLD RED, $_, RESET);
    } elsif (/^W/) {
        print(BOLD MAGENTA $_);
    } elsif (/^N/) {
        print(BOLD CYAN $_);
    } elsif (/^I/) {
        print(BOLD BLUE $_);
    } elsif (/^D/) {
        print(WHITE $_);
    } elsif (/^[0-9A-f]{2} [0-9A-f]{2}/) { # hexdumps
        print(BOLD YELLOW $_);
    } else {
        print;
    }
}

This script can also easily be extended to perform filtering operations or highlighting other useful information like e.g. NodeIds.

Opening Trace Files in Vim

For the Vim Editor there is a simple script which enables support for ANSI escape sequences. This makes the colors show up correctly in Vim.

Download: https://github.com/powerman/vim-plugin-AnsiEsc

Using a plugin manager like e.g. Vundle you need to add this line to your plugin config

Plugin 'powerman/vim-plugin-AnsiEsc'

and install using :VundleInstall.

After opening a file you can type :AnsiEsc to enable processing of the ANSI escape sequences. You can also automate this by adding the following snippet to your ~/.vimrc.

augroup VimAutoAnsiEsc
    autocmd!
    autocmd BufRead *.log AnsiEsc
augroup END

Table of Contents

File Trace

Adding/Removing Color from Trace Output

Removing Colors

Adding Colors

Opening Trace Files in Vim