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  <header>
    <copyright>
      <year>1996</year>
      <year>2013</year>
      <holder>Ericsson AB, All Rights Reserved</holder>
    </copyright>
    <legalnotice>
  The contents of this file are subject to the Erlang Public License,
  Version 1.1, (the "License"); you may not use this file except in
  compliance with the License. You should have received a copy of the
  Erlang Public License along with this software. If not, it can be
  retrieved online at http://www.erlang.org/.

  Software distributed under the License is distributed on an "AS IS"
  basis, WITHOUT WARRANTY OF ANY KIND, either express or implied. See
  the License for the specific language governing rights and limitations
  under the License.

  The Initial Developer of the Original Code is Ericsson AB.
    </legalnotice>

    <title>systools</title>
    <prepared></prepared>
    <docno></docno>
    <date></date>
    <rev></rev>
  </header>
  <module>systools</module>
  <modulesummary>A Set of Release Handling Tools.</modulesummary>
  <description>
    <p>This module contains functions to generate boot scripts
      (<c>.boot</c>, <c>.script</c>), release upgrade scripts
      (<c>relup</c>), and release packages.</p>
  </description>
  <funcs>
    <func>
      <name>make_relup(Name, UpFrom, DownTo) -> Result</name>
      <name>make_relup(Name, UpFrom, DownTo, [Opt]) -> Result</name>
      <fsummary>Generate a release upgrade file <c>relup</c>.</fsummary>
      <type>
        <v>Name = string()</v>
        <v>UpFrom = DownTo = [Name | {Name,Descr}]</v>
        <v>&nbsp;Descr = term()</v>
        <v>Opt = {path,[Dir]} | restart_emulator | silent | noexec | {outdir,Dir}
	| warnings_as_errors</v>
        <v>&nbsp;Dir = string()</v>
        <v>Result = ok | error | {ok,Relup,Module,Warnings} | {error,Module,Error}</v>
        <v>&nbsp;Relup - see relup(4)</v>
        <v>&nbsp;Module = atom()</v>
        <v>&nbsp;Warnings = Error = term()</v>
      </type>
      <desc>
        <p>Generates a release upgrade file <c>relup</c> containing a
          script which describes how to upgrade the system from a number
          of previous releases, and how to downgrade to a number of
          previous releases. The script is used by
          <c>release_handler</c> when installing a new version of a
          release in run-time.</p>
        <p>By default, <c>relup</c> is placed in the current working
          directory. If the option <c>{outdir,Dir}</c> is provided,
          <c>relup</c> is placed in <c>Dir</c> instead.</p>
        <p>The release resource file <c>Name.rel</c> is compared with
          all release resource files <c>Name2.rel</c> specified in
          <c>UpFrom</c> and <c>DownTo</c>. For each such pair, it is
          deducted:</p>
        <list type="bulleted">
          <item>
            <p>Which applications should be deleted, that is
              applications which are listed in <c>Name.rel</c> but not
              in <c>Name2.rel</c>.</p>
          </item>
          <item>
            <p>Which applications should be added, that is applications
              which are listed in <c>Name2.rel</c> but not in
              <c>Name.rel</c>.</p>
          </item>
          <item>
            <p>Which applications should be upgraded/downgraded, that
              is applications listed in both <c>Name.rel</c> and
              <c>Name2.rel</c>, but with different versions.</p>
          </item>
          <item>
            <p>If the emulator needs to be restarted after upgrading or
              downgrading, that is if the ERTS version differs between
              <c>Name.rel</c> and <c>Name2.rel</c>.</p>
          </item>
        </list>
        <p>Instructions for this are added to the <c>relup</c> script in
          the above order. Instructions for upgrading or downgrading
          between application versions are fetched from the relevant
          application upgrade files <c>App.appup</c>, sorted in
          the same order as when generating a boot script, see
          <c>make_script/1,2</c>. High-level instructions are translated
          into low-level instructions and the result is printed to
          <c>relup</c>.</p>
        <p>The optional <c>Descr</c> parameter is included as-is in
          the <c>relup</c> script, see <c>relup(4)</c>. Defaults to
          the empty list.</p>
        <p>All the files are searched for in the code path. It is
          assumed that the <c>.app</c> and <c>.appup</c> file for an
          application is located in the same directory.</p>
        <p>If the option <c>{path,[Dir]}</c> is provided, this path is
          appended to the current path. The wildcard <c>*</c> is
          expanded to all matching directories.
          Example: <c>lib/*/ebin</c>.</p>
        <p>If the <c>restart_emulator</c> option is supplied, a
          low-level instruction to restart the emulator is appended to
          the relup scripts. This ensures that a complete reboot of
          the system is done when the system is upgraded or downgraded.</p>
	<p>If an upgrade includes a change from an emulator earlier
	  than OTP R15 to OTP R15 or later, the warning
	  <c>pre_R15_emulator_upgrade</c> is issued. See <seealso
	  marker="doc/design_principles:appup_cookbook">Design
	  Principles</seealso> for more information about this.</p>
        <p>By default, errors and warnings are printed to tty and
          the function returns <c>ok</c> or <c>error</c>. If the option
          <c>silent</c> is provided, the function instead returns
          <c>{ok,Relup,Module,Warnings}</c> where <c>Relup</c> is
          the release upgrade script, or it returns
          <c>{error,Module,Error}</c>. Warnings and errors can be
          converted to strings by calling
          <c>Module:format_warning(Warnings)</c> or
          <c>Module:format_error(Error)</c>.</p>
        <p>If the option <c>noexec</c> is provided, the function returns
          the same values as for <c>silent</c> but no <c>relup</c> file
          is created.</p>
	<p>If the option <c>warnings_as_errors</c> is provided, warnings
	   are treated as errors.</p>
      </desc>
    </func>
    <func>
      <name>make_script(Name) -> Result</name>
      <name>make_script(Name, [Opt]) -> Result</name>
      <fsummary>Generate a boot script <c>.script/.boot</c>.</fsummary>
      <type>
        <v>Name = string()</v>
        <v>Opt = src_tests | {path,[Dir]} | local | {variables,[Var]} | exref |
	  {exref,[App]}] | silent | {outdir,Dir} | no_dot_erlang | no_warn_sasl |
	  warnings_as_errors</v>
        <v>&nbsp;Dir = string()</v>
        <v>&nbsp;Var = {VarName,Prefix}</v>
        <v>&nbsp;&nbsp;VarName = Prefix = string()</v>
        <v>&nbsp;App = atom()</v>
        <v>Result = ok | error | {ok,Module,Warnings} | {error,Module,Error}</v>
        <v>&nbsp;Module = atom()</v>
        <v>&nbsp;Warnings = Error = term()</v>
      </type>
      <desc>
        <p>Generates a boot script <c>Name.script</c> and its binary
          version, the boot file <c>Name.boot</c>. The boot file
          specifies which code should be loaded and which applications
          should be started when the Erlang runtime system is started.
          See <c>script(4)</c>.</p>
        <p>The release resource file <c>Name.rel</c> is read to find
          out which applications are included in the release. Then
          the relevant application resource files <c>App.app</c> are
          read to find out which modules should be loaded and if and
          how the application should be started. (Keys <c>modules</c>
          and <c>mod</c>, see <c>app(4)</c>).</p>
        <p>By default, the boot script and boot file are placed in
          the same directory as <c>Name.rel</c>. That is, in the current
          working directory unless <c>Name</c> contains a path. If
          the option <c>{outdir,Dir}</c> is provided, they are placed
          in <c>Dir</c> instead.</p>
        <p>The correctness of each application is checked:</p>
        <list type="bulleted">
          <item>
            <p>The version of an application specified in
              the <c>.rel</c> file should be the same as the version
              specified in the <c>.app</c> file.</p>
          </item>
          <item>
            <p>There should be no undefined applications, that is,
              dependencies to applications which are not included in
              the release. (Key <c>applications</c> in <c>.app</c>
              file).</p>
          </item>
          <item>
            <p>There should be no circular dependencies among
              the applications.</p>
          </item>
          <item>
            <p>There should be no duplicated modules, that is, modules with
              the same name but belonging to different applications.</p>
          </item>
          <item>
            <p>If the <c>src_tests</c> option is specified, a
              warning is issued if the source code for a module is
              missing or newer than the object code.</p>
          </item>
        </list>
        <p>The applications are sorted according to the dependencies
          between the applications. Where there are no dependencies,
          the order in the <c>.rel</c> file is kept.</p>
	<p>The function will fail if the mandatory
	  applications <c>kernel</c> and <c>stdlib</c> are not
	  included in the <c>.rel</c> file and have start
	  type <c>permanent</c> (default).</p>
	<p>If <c>sasl</c> is not included as an application in
	  the <c>.rel</c> file, a warning is emitted because such a
	  release can not be used in an upgrade. To turn off this
	  warning, add the option <c>no_warn_sasl</c>.</p>
        <p>All files are searched for in the current path. It is
          assumed that the <c>.app</c> and <c>.beam</c> files for an
          application is located in the same directory. The <c>.erl</c>
          files are also assumed to be located in this directory, unless
          it is an <c>ebin</c> directory in which case they may be
          located in the corresponding <c>src</c> directory.</p>
        <p>If the option <c>{path,[Dir]}</c> is provided, this path is
          appended to the current path. A directory in the path can be
          given with a wildcard <c>*</c>, this is expanded to all
          matching directories. Example: <c>"lib/*/ebin"</c>.</p>
        <p>In the generated boot script all application directories are
          structured as <c>App-Vsn/ebin</c> and assumed to be located
          in <c>$ROOT/lib</c>, where <c>$ROOT</c> is the root directory
          of the installed release. If the <c>local</c> option is
          supplied, the actual directories where the applications were
          found are used instead. This is a useful way to test a
          generated boot script locally.</p>
        <p>The <c>variables</c> option can be used to specify an
          installation directory other than <c>$ROOT/lib</c> for some of
          the applications. If a variable <c>{VarName,Prefix}</c> is
          specified and an application is found in a directory
          <c>Prefix/Rest/App[-Vsn]/ebin</c>, this application will get
          the path <c>VarName/Rest/App-Vsn/ebin</c> in the boot script.
          If an application is found in a directory <c>Prefix/Rest</c>,
          the path will be <c>VarName/Rest/App-Vsn/ebin</c>. When
          starting Erlang, all variables <c>VarName</c> are given
          values using the <c>boot_var</c> command line flag.</p>
        <p>Example: If the option <c>{variables,[{"TEST","lib"}]}</c> is
          supplied, and <c>myapp.app</c> is found in
          <c>lib/myapp/ebin</c>, then the path to this application in
          the boot script will be <c>"$TEST/myapp-1/ebin"</c>. If
          <c>myapp.app</c> is found in <c>lib/test</c>, then the path
          will be <c>$TEST/test/myapp-1/ebin</c>.</p>
        <p>The checks performed before the boot script is generated can
          be extended with some cross reference checks by specifying
          the <c>exref</c> option. These checks are performed with
          the Xref tool. All applications, or the applications specified
          with <c>{exref,[App]}</c>, are checked by Xref and
          warnings are generated for calls to undefined functions.</p>
        <p>By default, errors and warnings are printed to tty and
          the function returns <c>ok</c> or <c>error</c>. If the option
          <c>silent</c> is provided, the function instead returns
          <c>{ok,Module,Warnings}</c> or <c>{error,Module,Error}</c>.
          Warnings and errors can be converted to strings by calling
          <c>Module:format_warning(Warnings)</c> or
          <c>Module:format_error(Error)</c>.</p>
	<p>If the option <c>warnings_as_errors</c> is provided, warnings
	   are treated as errors.</p>
	<p>If the option <c>no_dot_erlang</c> is provided, the instruction to
	   load the <c>.erlang</c> file during boot is <em>NOT</em> included.</p>
      </desc>
    </func>
    <func>
      <name>make_tar(Name) -> Result</name>
      <name>make_tar(Name, [Opt]) -> Result</name>
      <fsummary>Create a release package.</fsummary>
      <type>
        <v>Name = string()</v>
        <v>Opt = {dirs,[IncDir]} | {path,[Dir]} | {variables,[Var]} | {var_tar,VarTar} | {erts,Dir} | src_tests | exref | {exref,[App]} | silent | {outdir,Dir}</v>
        <v>&nbsp;Dir = string()</v>
        <v>&nbsp;IncDir = src | include | atom()</v>
        <v>&nbsp;Var = {VarName,PreFix}</v>
        <v>&nbsp;&nbsp;VarName = Prefix = string()</v>
        <v>&nbsp;VarTar = include | ownfile | omit</v>
        <v>&nbsp;Machine = atom()</v>
        <v>&nbsp;App = atom()</v>
        <v>Result = ok | error | {ok,Module,Warnings} | {error,Module,Error}</v>
        <v>&nbsp;Module = atom()</v>
        <v>&nbsp;Warning = Error = term()</v>
      </type>
      <desc>
        <p>Creates a release package file <c>Name.tar.gz</c>. file.
          This file must be uncompressed and unpacked on the target
          system using the <c>release_handler</c>, before the new
          release can be installed.</p>
        <p>The release resource file <c>Name.rel</c> is read to find out
          which applications are included in the release. Then
          the relevant application resource files <c>App.app</c> are
          read to find out the version and modules of each application.
          (Keys <c>vsn</c> and <c>modules</c>, see <c>app(4)</c>).</p>
        <p>By default, the release package file is placed in the same
          directory as <c>Name.rel</c>. That is, in the current working
          directory unless <c>Name</c> contains a path. If the option
          <c>{outdir,Dir}</c> is provided, it is placed in <c>Dir</c>
          instead.</p>
        <p>By default, the release package contains the directories
          <c>lib/App-Vsn/ebin</c> and <c>lib/App-Vsn/priv</c> for each
          included application. If more directories, the option
          <c>dirs</c> is supplied. Example:
          <c>{dirs,[src,examples]}</c>.</p>
        <p>All these files are searched for in the current path. If
          the option <c>{path,[Dir]}</c> is provided, this path is
          appended to the current path. The wildcard <c>*</c> is
          expanded to all matching directories.
          Example: <c>"lib/*/ebin"</c>.</p>
        <p>The <c>variables</c> option can be used to specify an
          installation directory other than <c>lib</c> for some of
          the applications. If a variable <c>{VarName,Prefix}</c> is
          specified and an application is found in a directory
          <c>Prefix/Rest/App[-Vsn]/ebin</c>, this application will be
          packed into a separate <c>VarName.tar.gz</c> file as
          <c>Rest/App-Vsn/ebin</c>.</p>
        <p>Example: If the option <c>{variables,[{"TEST","lib"}]}</c> is
          supplied, and <c>myapp.app</c> is found in
          <c>lib/myapp-1/ebin</c>, the the application <c>myapp</c> is
          included in <c>TEST.tar.gz</c>:</p>
        <pre>
% <input>tar tf TEST.tar</input>
myapp-1/ebin/myapp.app
...
        </pre>
        <p>The <c>{var_tar,VarTar}</c> option can be used to specify if
          and where a separate package should be stored. In this option,
          <c>VarTar</c> is:</p>
        <list type="bulleted">
          <item>
            <p><c>include</c>. Each separate (variable) package is
              included in the main <c>ReleaseName.tar.gz</c> file. This
              is the default.</p>
          </item>
          <item>
            <p><c>ownfile</c>. Each separate (variable) package is
              generated as separate files in the same directory as
              the <c>ReleaseName.tar.gz</c> file.</p>
          </item>
          <item>
            <p><c>omit</c>. No separate (variable) packages are
              generated and applications which are found underneath a
              variable directory are ignored.</p>
          </item>
        </list>
        <p>A directory called <c>releases</c> is also included in
          the release package, containing <c>Name.rel</c> and a
          subdirectory called <c>RelVsn</c>. <c>RelVsn</c> is
          the release version as specified in <c>Name.rel</c>.</p>
        <p><c>releases/RelVsn</c> contains the boot script
          <c>Name.boot</c> renamed to <c>start.boot</c> and, if found,
          the files <c>relup</c> and <c>sys.config</c>. These files
          are searched for in the same directory as <c>Name.rel</c>,
          in the current working directory, and in any directories
          specified using the <c>path</c> option.</p>
        <p>If the release package should contain a new Erlang runtime
          system, the <c>bin</c> directory of the specified runtime
          system <c>{erts,Dir}</c> is copied to <c>erts-ErtsVsn/bin</c>.</p>
        <p>All checks performed with the <c>make_script</c> function
          are performed before the release package is created. The
          <c>src_tests</c> and <c>exref</c> options are also
          valid here.</p>
        <p>The return value and the handling of errors and warnings
          are the same as described for <c>make_script</c> above.</p>
      </desc>
    </func>
    <func>
      <name>script2boot(File) -> ok | error</name>
      <fsummary>Generate a binary version of a boot script.</fsummary>
      <type>
        <v>File = string()</v>
      </type>
      <desc>
        <p>The Erlang runtime system requires that the contents of
          the script used to boot the system is a binary Erlang term.
          This function transforms the <c>File.script</c> boot script
          to a binary term which is stored in the file <c>File.boot</c>.</p>
        <p>A boot script generated using the <c>make_script</c>
          function is already transformed to the binary form.</p>
      </desc>
    </func>
  </funcs>

  <section>
    <title>SEE ALSO</title>
    <p>app(4), appup(4), erl(1), rel(4), release_handler(3), relup(4),
      script(4)</p>
  </section>
</erlref>

