0.8.26 Release

• guid: 55950e64-fa4e-4eb9-9a3a-2c73d9cd6478
• author: Markus Raab
• pubDate: Tue, 26 Feb 2019 15:31:09 +0100
• shortDesc: high-level API

We are proud to release Elektra 0.8.26 with the new high-level API.

What is Elektra?

Elektra serves as a universal and secure framework to access configuration settings in a global, hierarchical key database. For more information, visit https://libelektra.org.

You can also read the news on our website

High-Level API

The new high-level API provides an easier way for applications to get started with Elektra.

To use Elektra in an application (including proper error handling) you now only need a few self-explanatory lines of code:

ElektraError * error = NULL;
Elektra * elektra = elektraOpen ("/sw/org/myapp/#0/current", NULL, &error);
if (elektra == NULL)
{
    printf ("An error occurred: %s", elektraErrorDescription (error));
    elektraErrorReset (&error);
    return -1;
}

// Once you have an instance of `Elektra` you simply call one of the typed `elektraGet*` functions to read a value:

kdb_long_t mylong = elektraGetLong (elektra, "mylong");
printf ("got long " ELEKTRA_LONG_F "\n", mylong);
const char * mystring = elektraGetString (elektra, "mystring");
printf ("got string %s\n", mystring);

elektraClose (elektra);

To run the application, the configuration should be specified, e.g., for mylong:

sudo kdb setmeta /sw/org/myapp/#0/current/mylong type long
sudo kdb setmeta /sw/org/myapp/#0/current/mylong default 5

In the getters/setters there is no need to convert types or to specify the base path /sw/org/myapp/#0/current, as the high-level API does that for you. The API supports the CORBA types already used by the plugins. The high-level API should also be used in combination with a specification (spec-mount). When used this way, the API is designed to be error and crash free while reading values. Writing values, can of course still produce errors.

Another advantage of the new API is, that it will be much easier to write bindings for other languages now, because only a few simple types and functions have to be mapped to provide the full functionality.

Take a look at the README for more information.

Because of the high-level API, we now have the new header files elektra.h and a folder elektra in Elektra's include directory. Furthermore, we install the library libelektra-highlevel.so and the pkgconfig file elektra-highlevel.pc for easier detection.

For an example on how to build an application using this API take a look at this.

A big thanks to Klemens Böswirth for making this possible. Also big thanks to Dominik Hofer, who did all the foundation work for this API.

Plugins

The following section lists news about the plugins we updated in this release.

Augeas

• We changed the default Augeas directory prefix for the lenses directory on macOS to the one used by Homebrew: /usr/local. (René Schwaiger)

Network

• The network plugin also supports port declarations to check if a port number is valid or if the port is available to use. (Michael Zronek)
• We added a Markdown Shell Recorder test to the ReadMe of the plugin. (René Schwaiger)

YAMBi

• The build system does not print a warning about a deprecated directive any more, if you build the plugin with Bison 3.3 or later. (René Schwaiger)
• YAMBi now handles comments at the end of input properly. (René Schwaiger)

YanLR

• We improved the error reporting capabilities of the plugin. It now stores all of the error message reported by ANTLR and also specifies the line and column number of syntax errors. We also visualize these error messages in a similar way as modern compilers like Clang or GCC. For example, for the following erroneous input:

  key: - element 1
  - element 2 # Incorrect Indentation!
  

  the plugin currently prints an error message that looks like this:

  config.yaml:2:1: mismatched input '- ' expecting end of map
                   - element 2 # Incorrect Indentation!
                   ^^
  config.yaml:2:37: extraneous input 'end of map' expecting end of document
                    - element 2 # Incorrect Indentation!
                                                        ^
  

  . The inspiration for this feature was taken from the book “The Definitive ANTLR 4 Reference” by Terence Parr. (René Schwaiger)

• Yan LR’s lexer now

  • handles comment at the end of a YAML document correctly,
  • stores a more human-readable description in tokens (e.g. end of map instead of MAP END)

  . (René Schwaiger)

Path

Enhanced the plugin to also check for concrete file or directory permissions such as rwx. For example, you can specify that a user can write to a certain directory or file which prevents applications of runtime failures once they try to access the given path (such as a log directory or file). Simply add check/path/user <user> and check/path/mode <modes> as specification (metadata) and be assured that you can safely set a path value to the key. A more detailed explanation can be found here (Michael Zronek)

YAwn

• The plugin now handles comments at the end of a file properly. (René Schwaiger)
• We improved the syntax error messages of the plugin. (René Schwaiger)
• We fixed a memory leak that occurred, if a YAML file contained syntax errors. (René Schwaiger)

YAy PEG

• The new plugin YAy PEG parses a subset of YAML using a parser based on PEGTL. (René Schwaiger)

Ruby

• Added some basic unit tests (Bernhard Denner)

Misc

• We fixed some compiler warnings for the plugins

  • camel,
  • line,
  • mini and
  • resolver

  reported on FreeBSD. (René Schwaiger)

• The resolver plugin and its tests now better support KDB_DB_SYSTEM and KDB_DB_SPEC paths using ~ to refer to a home directory. (Klemens Böswirth)

• If KDB_DB_SYSTEM is set to a relative path, it is now treated as relative to CMAKE_INSTALL_PREFIX. This ensures that KDB_DB_SYSTEM actually points to the same location no matter the current working directory. (Klemens Böswirth)

Libraries

The text below summarizes updates to the C (and C++)-based libraries of Elektra.

Compatibility

As always, the ABI and API of kdb.h is fully compatible, i.e. programs compiled against an older 0.8 version of Elektra will continue to work (ABI) and you will be able to recompile programs without errors (API).

We have two minor incompatible changes:

• we now support larger array numbers (i.e. the larger numbers are not an error anymore)
• elektraArrayValidateBaseNameString returns the offset to the first digit of the array index instead of 1

For details of the changes see below Core and Libease.

Core

• All plugins in the KDB now get a handle to a global keyset via elektraPluginGetGlobalKeySet(), for communication between plugins. See Global KeySet Handle for details. (Mihael Pranjić)
• elektraWriteArrayNumber now uses kdb_long_long_t for array indices to be compatible with the high level API. Similarly the value of ELEKTRA_MAX_ARRAY_SIZE was changed to match this. (Klemens Böswirth)

Libease

• The function elektraArrayValidateBaseNameString now returns the offset to the first digit of the array index, if the given string represents an array element containing an index. This update enhances the behavior of the function. Now it not only tells you if a name represents a valid array element, but also the start position of the array index.

  elektraArrayValidateBaseNameString ("#_10");
  //                                     ~~^ Returns `2` (instead of `1`)
  
  elektraArrayValidateBaseNameString ("#___1337");
  //                                   ~~~~^ Returns `4` (instead of `1`)
  

  If your program already used elektraArrayValidateBaseNameString and you check for a valid array element using the equality operator (== 1), then please use (>= 1) instead. For example, if you code that looks like this:

  if (elektraArrayValidateBaseNameString(baseName) == 1) …;
  

  , please update your code to check for a valid array element name like this:

  if (elektraArrayValidateBaseNameString(baseName) >= 1) …;
  

  . (René Schwaiger)

Libopts

• This is a new library containing only the function elektraGetOpts. This function can be used to parse command line arguments and environment variables and add their values to keys in the proc namespace.

  You can use opt, opt/long and env to specify a short, a long option and an environment variable. For more information take a look at the tutorial and the code documentation of elektraGetOpts. (Klemens Böswirth)

Tools

• kdb spec-mount correctly includes type plugin to validate type. (Markus Raab)
• kdb setmeta reports if it removed a metakey. (Markus Raab)
• system/elektra/version now has metadata to indicate that it cannot be edited or removed. (Dominic Jäger)

Scripts

• The script reformat-source now also handles filenames containing spaces correctly. (René Schwaiger)
• The script reformat-markdown formats Markdown files in the repository with prettier. (René Schwaiger)
• The scripts reformat-source, reformat-cmake, reformat-shfmt and reformat-markdown don't format files that are ignored by Git anymore. (Klemens Böswirth)

Documentation

• We fixed various spelling mistakes. (René Schwaiger)
• The documentation for elektraMetaArrayToKS was fixed. It now reflects the fact that the parent key is returned as well. (Klemens Böswirth)

Tests

• The tests for the IO bindings and notification plugins now use increased timeout values so that the test suite fails less often on machines with high load. (René Schwaiger)
• We update most of the Markdown Shell Recorder tests so they use an explicit namespace (like system or user). This has the advantage that the output of these tests does not change depending on the user that executes them. Before the update these tests used cascading keys. (René Schwaiger)
• The Shell Recorder now also works correctly on FreeBSD. (René Schwaiger)
• Fix memcheck target to detect memory problems again and enabled parallel testing to speed it up. (Mihael Pranjić)
• Fix memleak in pluginprocess tests. (Mihael Pranjić)
• The test check-env-dep does not require Bash anymore. (René Schwaiger)
• We fixed an incorrect directive in the Markdown Shell Recorder test of the Type Checker plugin. (René Schwaiger)
• We added a test that invokes the script fix-spelling to check the documentation for common spelling mistakes. (René Schwaiger)
• We added a test that checks the formatting of Markdown files with prettier. (René Schwaiger)
• The test testscr_check_formatting now prints instructions that show you how to fix formatting problems. (René Schwaiger)

Build

CMake

Misc

• The plugin name is now provided as compiler definition ELEKTRA_PLUGIN_NAME via CMake. See #1042. (Peter Nirschl)
• ELEKTRA_PLUGIN_FUNCTION does not require the module name as parameter any more, instead the ELEKTRA_PLUGIN_NAME compiler definition is being used. See #1042. (Peter Nirschl)
• ELEKTRA_README, and ELEKTRA_PLUGIN_EXPORT do not require the module name as parameter any more, instead the ELEKTRA_PLUGIN_NAME compiler definition is being used. See #1042. (Peter Nirschl)
• We now specify
  • version number,
  • project description, and
  • homepage URL in the CMake project command. (René Schwaiger)
• We fixed the detection of Python for the Python 2 binding on macOS. (René Schwaiger)
• You can now use the Ruby binding and plugin without any manual configuration, if you installed Ruby (version 2.5 or later) via Homebrew. (René Schwaiger)

Find Modules

• The CMake find module FindAugeas.cmake does not print an error message anymore, if it is unable to locate Augeas in the pkg-config search path. (René Schwaiger)
• The CMake find module FindLua.cmake does not print an error message anymore, if it is unable to locate a Lua executable. (René Schwaiger)
• We added code that makes sure you can compile IO GLIB on macOS, even if pkg-config erroneously reports that GLIB requires linking to the library intl (part of GNU gettext). (René Schwaiger)
• We added a CMake find module for GLib. The module makes sure you can compile and link IO GLib on macOS. (René Schwaiger)
• The CMake find module FindLibOpenSSL.cmake does not require pkg-config anymore. The updated code also fixes some linker problems on macOS (and probably other operating systems too), where the build system is not able to link to OpenSSL using only the name of the OpenSSL libraries. (René Schwaiger)
• We simplified the CMake find module FindLibgcrypt.cmake.The update fixes problems on macOS, where the build system excluded the plugin crypto_gcrypt, although Libgcrypt was installed on the system. (René Schwaiger)
• We now use the official CMake find module for iconv. This update fixes linker problems with the iconv and filecheck plugin on FreeBSD 12. (René Schwaiger)
• The CMake find module for Botan does not require pkg-config anymore. (René Schwaiger)
• The CMake find module for libgit2 now also exports the version number of libgit2. (René Schwaiger)
• We added a CMake find module for libuv and fixed a problem on macOS, where the build system was unable to locate the header file of libuv. (René Schwaiger)
• We added a CMake find module for ZeroMQ to fix build problems on macOS. (René Schwaiger)

Docker

• We added

  • ANTLR,
  • ANTLR’s C++ runtime,
  • Ninja, and
  • shfmt, to the Dockerfile for Debian sid

  . (René Schwaiger)

Misc

• We removed the configure script from the top-level directory. CMake is now popular enough so that this helper-script is not needed. (René Schwaiger)

Infrastructure

Cirrus

• We now use Cirrus CI to build and test Elektra on

  • FreeBSD 11.2 and
  • FreeBSD 12.0

  . Both of these build jobs use -Werror to make sure we do not introduce any code that produces compiler warnings. (René Schwaiger)

• The new build job 🍎 Clang tests Elektra on macOS. (René Schwaiger)

• We added the build job 🍎 Clang ASAN, which uses Clang with enabled AddressSanitizer to test Elektra on macOS. (René Schwaiger)

• The new build job 🍎 FULL compiles and test Elektra using the CMake options BUILD_SHARED=OFF an BUILD_FULL=ON. (René Schwaiger)

• We added 🍎 MMap, which tests Elektra using mmapstorage as default storage module. (René Schwaiger)

• We install and uninstall Elektra in all of the macOS build jobs to make sure that ElektraUninstall.cmake removes all of the installed files. (René Schwaiger)

Jenkins

• We added a badge displaying the current build status to the main ReadMe. (René Schwaiger)
• The build job formatting-check now also checks the formatting of Shell scripts. (René Schwaiger)

Travis

• We now test Elektra on Ubuntu Xenial Xerus. (René Schwaiger)
• We removed the build jobs 🍏 Clang and 🍏 Check Shell in favor of the Cirrus build job 🍎 Clang. (René Schwaiger)
• We removed the build jobs 🍏 Clang ASAN in favor of the Cirrus build job 🍎 Clang ASAN. (René Schwaiger)
• We removed the build jobs 🍏 FULL in favor of the Cirrus build job 🍎 FULL. (René Schwaiger)
• We removed the build jobs 🍏 MMap in favor of the Cirrus build job 🍎 MMap. (René Schwaiger)

Website

The website is generated from the repository, so all information about plugins, bindings and tools are always up-to-date.

Outlook

We are currently working on following topics:

• infallible high-level API: creating an API that guarantees you to return configuration values (Klemens Böswirth)
• error handling (Michael Zronek)
• elektrify LCDproc (Klemens Böswirth) and (Michael Zronek)
• YAML as default storage (René Schwaiger)
• misconfiguration tracker (Vanessa Kos)
• global mmap cache: This feature will enable Elektra to return configuration without parsing configuration files or executing other plugins as long as the configuration files are not changed. (Mihael Pranjić)

and since recently:

• automatic shell completion (Ulrike Schaefer)
• plugin framework improvements (Vid Leskovar)
• 3-way merge (Dominic Jäger)
• reducing entry barriers for newcomers (Hani Torabi Makhsos)
• bug fixing (Usama Morad) and (Kurt Micheli)

Statistics

In this release we created 986 commits in which 802 files were changed, with 21687 insertions(+) and 6912 deletions(-).

Following authors made this release possible:

Join the Initiative!

We welcome new contributors! Read here about how to get started.

As first step, you could give us feedback about these release notes. Contact us via our issue tracker.

Get the Release!

You can download the release from here or GitHub

The hashsums are:

• name: elektra-0.8.26.tar.gz
• size: 6395865
• md5sum: 4ef202b5d421cc497ef05221e5309ebc
• sha1: 94f654764bcf49d0ebc7e636f444e24ca6cfeb19
• sha256: 5806cd0b2b1075fe0d5a303649d0bd9365752053e86c684ab7c06e7f369155d3

The release tarball is also available signed by Markus Raab using GnuPG from here or on GitHub

Already built API documentation can be found here or on GitHub.

Stay tuned!

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If you also want to participate, or for any questions and comments please contact us via our issue tracker on GitHub.

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For more information, see https://libelektra.org

Best regards, Elektra Initiative