I have the following default target defined in my build file:
<target name="main" depends="generate.doc" unless="generated.doc.present"/>
The property is set when the doc files already exist. In that case I don't want to do anything. However, it doesn't work since the dependent target is always executed before the condition is evaluated.
I still need to be able to call the dependent target directly and execute it, no matter if the output already exists or not. Hence something like this would not work:
<target name="main" depends="generate.doc"/>
<target name="generate.doc" unless="generated.doc.present">...</target>
Is there a solution without using antcall in the main target?
In the example below, the main <target> has been changed to have two dependencies. A new <target> named -pre-conditions will run before generate.doc.
The -pre-conditions <target> sets the skip-generate.doc property only if the generated.doc.present property has already been set.
The generate.doc <target> has been changed so it will be skipped if -pre-conditions set the skip-generate.doc property.
With these changes, generate.doc will always run when it's called directly.
<target name="-pre-conditions">
<condition property="skip-generate.doc">
<isset property="generated.doc.present"/>
</condition>
</target>
<target name="main" depends="-pre-conditions, generate.doc"/>
<target name="generate.doc" unless="skip-generate.doc">
<echo>generate.doc running</echo>
</target>
Related
I have a build.xml that should receive dynamically parameters to the depends field.
I define this parameter in some other app.xml such as:
ops=op1, op2, op3,op4,op5,.... opn
then I import this app.xml into build.xml and want to use the parameter ops there.
<project name="Project" basedir="." default="help">
<target name="test" depends="{$ops}" description="executea series of commands in ant">
<echo message="batch operation job done. tasks = {$ops}"/>
</target>
</project>
How can I pass a parameter from one ant file to another?
The depends parameter does not take properties.
Ant uses a dependency matrix to determine what should be built and in what order. This matrix is calculated before any part of the build file itself is executed, so properties aren't even set when this is done.
What are you trying to accomplish? Maybe if we have a better idea what you want, we can help you with it. Ant isn't a scripting language like BASH or Python.
As already mentioned, you can't put properties into the Depends field. However, if you are setting a property, you can use it in the If field. Example
<project name="appProject">
<target name="test" depends="target1,target2,target3" description="execute series of commands"/>
<target name="target1" if="do.target1">
<echo message="Target1 executed." />
</target>
<target name="target2" if="do.target2">
<echo message="Target2 executed." />
</target>
<target name="target3" if="do.target3">
<echo message="Target3 executed." />
</target>
</project>
Then you set in your build.xml the given target flag do.target1, do.target2 or do.target3 and it gets executed. Basically what you wanted to have. In the If field properties are only checked for value. Also, you don't have to use the ${ } construction for the properties.
I would like to call target backup.yes only if the condition is true.
<condition property="directory.found.yes">
<equals arg1="${directory.found}" arg2="true"/>
</condition>
<antcall target="update.backup"/>
Is there any way to do this.
Instead of <antcall/>, do the following:
Imagine you're calling target foo, and you want to do a backup before, but only if that condition exists:
<target name="foo"
depends="update.backup">
<..../>
</target>
<target name="update.backup.test">
<condition property="directory.found.yes">
<equals arg1="${directory.found}" arg2="true"/>
</condition>
</target>
<target name="update.backup"
depends="update.backup.test"
if="directory.found.yes">
<.../>
</target>
The problem with <antcall/> is that it is used when the dependency matrix Ant uses is broken, and it's used to force a task to be done before another task is complete. When really abused, you'll end up calling the same task multiple times. I had a project here that literally called each target between 10 to 14 times, and there were over two dozen targets. I rewrote the entire build sans <antcall/> and by using true dependency setup, cut the build time by 75%.
From my experience 90% of <antcall/> is due to poor target dependency management.
Let's say you want to execute target foo. (The target the user wants to really execute), and before foo is called, you want to do your backup, but only if the directory actually exists.
In the above, foo is called. It depends upon update.backaup. The target update.backup is called, but it depends upon update.backup.test which will test whether or not the directory actually exists.
If the directory exists, the if clause on the update.backup task is true, and the task will actually execute. Otherwise, if the directory isn't there, it won't execute.
Note that update.backup first calls any dependencies before it checks whether the property on the if or unless parameter for the target entity is checked. This allows the target to call a test before it attempts to execute.
This is not a mere side effect, but built into the design of Ant. In fact, the Ant Manual on Targets](http://ant.apache.org/manual/targets.html) specifically gives a very similar example:
<target name="myTarget" depends="myTarget.check" if="myTarget.run">
<echo>Files foo.txt and bar.txt are present.</echo>
</target>
<target name="myTarget.check">
<condition property="myTarget.run">
<and>
<available file="foo.txt"/>
<available file="bar.txt"/>
</and>
</condition>
</target>
And states:
Important: the if and unless attributes only enable or disable the target to which they are attached. They do not control whether or not targets that a conditional target depends upon get executed. In fact, they do not even get evaluated until the target is about to be executed, and all its predecessors have already run.
You can do the following
In the other target:
<antcall target="update.back">
<param name="ok" value="${directory.found.yes}"/>
</antcall>
And in the update.backup target:
<target name="update.backup" if="ok">
But I think you can also do the following using the if statement from ant-contrib:
<if>
<equals arg1="${directory.found.yes}" arg2="true" />
<then>
<antcall target="update.back" />
</then>
</if>
I want to use manifestclasspath Ant task. I have a very large build.xml file with a couple of imported other build files and when I run it I get this:
build.xml:1289: The following error occurred while executing this line:
build.xml:165: Property 'some.property' already set!
I am sure that this property is defined only in manifestclasspath task. Here is my code:
<manifestclasspath property="some.property" jarfile="some.jar">
<classpath refid="some.classpath"/>
</manifestclasspath>
This code is located inside of <project>.
What am I doing wrong? Is there a way to add something like condition to set property only if it is not already set? I don't want to use custom Ant tasks such as Ant Contrib's if if there is other way around.
Antcall opens a new project scope, but by default, all of the properties of the current project will be available in the new project. Also if you used something like =
<antcall target="whatever">
<param name="some.property" value="somevalue"/>
</antcall>
in the calling project then ${some.property} is also already set and won't be overwritten, as properties once set are immutable in ant by design.
Alternatively, you may set the inheritAll attribute to false and only "user" properties (those passed on the command-line with -Dproperty=value) will be passed to the new project.
So, when ${some.property} ain't no user property, then use inheritAll="false" and you're done.
btw. it's better to use a dependency between targets via depends="..." attribute than to use antcall, because it opens a new project scope and properties set in the new project won't get back to the calling target because it lives in another project scope..
Following a snippet, note the difference, first without inheritAll attribute
<project default="foo">
<target name="foo">
<property name="name" value="value1" />
<antcall target="bar"/>
</target>
<target name="bar">
<property name="name" value="value2" />
<echo>$${name} = ${name}</echo>
</target>
</project>
output :
[echo] ${name} = value1
second with inheritAll=false
<project default="foo">
<target name="foo">
<property name="name" value="value1" />
<antcall target="bar" inheritAll="false" />
</target>
<target name="bar">
<property name="name" value="value2" />
<echo>$${name} = ${name}</echo>
</target>
</project>
output :
[echo] ${name} = value2
some rules of thumb for antcall, it's rarely used for good reasons :
1. it opens a new project scope (starting a new 'ant -buildfile yourfile.xml yourtarget') so it uses more memory, slowing down your build
2. depending targets of the called target will be called also !
3. properties don't get passed back to the calling target
In some cases it might be ok when calling the same 'standalone' target (a target that has no target it depends on) with different params for reuse. Normally macrodef or scriptdef are used for that purpose. So, think twice before using antcall which also puts superfluous complexity to your scripts, because it works against the normal flow.
Answer to your question in the comment, using a dependency graph instead of antcall
you have some target that holds all conditions and sets the appropriate properties which may be evaluated by targets via if and unless attributes to control the further flow
<project default="main">
<target name="some.target">
<echo>starting..</echo>
</target>
<!-- checking requirements.. -->
<target name="this.target">
<condition property="windowsbuild">
<os family="windows"/>
</condition>
<condition property="windowsbuild">
<os family="unix"/>
</condition>
<!-- ... -->
</target>
<!-- alternatively
<target name="yet.another.target" depends="this.target" if="unixbuild">
-->
<target name="another.target" depends="this.target" unless="windowsbuild">
<!-- your unixspecific stuff goes here .. -->
</target>
<!-- alternatively
<target name="yet.another.target" depends="this.target" if="windowsbuild">
-->
<target name="yet.another.target" depends="this.target" unless="unixbuild">
<!-- your windowspecific stuff goes here .. -->
</target>
Dear, I currently face some problem to retrieve the value of a property setted in a foreach loop. Maybe one of you could help me...
The purpose is to check if one file of a folder has been modified since the corresponding jar has been generated. This way I know if I have to generate the jar again.
What I do is to go through the folder with a foreach loop and if one file match my test, set a property to true.
The problem is that my variable doesn't seems to exist after my loop... Here is a simplified code example that has the same problem:
<target name="target">
<taskdef resource="net/sf/antcontrib/antlib.xml" classpath="${lib.dir}/ant-contrib.jar"></taskdef>
<foreach target="setVar" param="var" list="a,b"/>
<echo>myreturn in target: ${env.myreturn}</echo>
<property name="env.myreturn" value="c"/>
<echo>myreturn in second: ${env.myreturn}</echo>
</target>
<target name="setVar">
<property name="env.myreturn" value="${var}"/>
<echo>myreturn in setVar: ${env.myreturn}</echo>
</target>
The result of this code is:
target:
setVar:
[echo] myreturn in setVar: a
setVar:
[echo] myreturn in setVar: b
[echo] myreturn in target: ${env.myreturn}
[echo] myreturn in second: c
BUILD SUCCESSFUL
It seems that the variable is correctly set as it could be printed in the "setVar" target but no way to retrieve value from the calling target.
I also know it's not possible to assign a value to a property twice. But the problem doesn't even occurs... When it'll be the case I could add a check on the value of the property before to assign it to be sure it is not already initialized...
Do you have a clue on the way I can solve my problem ???
Many thanks in advance for your help :)
Try <for> task from ant-contrib instead of <foreach>. The <for> task takes advantage of Ant macro facility that came later. It works faster and is more flexible than the older <foreach> task. You are in the same project context when using <for>. That means properties set in the loop will be visible outside of the loop. Of course, normal rules for properties apply... you only get to set it once... unless you use <var> task from ant-contrib to overwrite or unset previously set properties.
Ah the joys of Ant hacking.
Not sure about your foreach problem, but can you not use the uptodate task for your requirement?
Even if I don't need it anymore thanks to sudocode, I found a solution for my question. Maybe it could be useful for someone else...
A collegue talked about the "antcallback" target of ant-contrib: it allows to return a result from a called target to the calling one. With a combination of "for" target and "antcallback" it is possible to do what I wanted to do:
<target name="target">
<taskdef resource="net/sf/antcontrib/antlib.xml" classpath="${lib.dir}/ant-contrib.jar"></taskdef>
<for param="file">
<path>
<fileset dir="../myDirectory" includes="**/*" />
</path>
<sequential>
<antcallback target="setVar" return="retValue">
<param name="file" value="#{file}"/>
</antcallback>
</sequential>
</for>
<echo>result: ${retValue}</echo>
</target>
<target name="setVar">
<property name="retValue" value="${file}"/>
</target>
"file" contains the name of the file in the directory. It is given to the called target as parameter with value "#{file}" ('#' necessary due to "for" target implementation).
At the end of the main target, ${retValue} contains the first value setted by the "setVar" target. No error is thrown when trying to set it multiple times, so it's not necessary to check if variable has already been instantiated before to set it in "setVar" target.
The <foreach> task uses the same logic as <antcall> under the covers, and any proprrties set inside a target invoked by <antcall> do not have scope beyond the execution of that target.
In other words, the env.myreturn property that you define in the setVar target is lost as soon as execution of that target completes.
This sort of scripting really isn't what Ant is designed for. The Ant-contrib library tries to patch up the holes, but it's still bending it way out of shape.
If you need to write such scripts, and want to use Ant tasks to achieve them, have a look at Gradle instead. It's a rather lovely blend of Groovy (for scripting) and Ant (for the tasks).
The other approaches here (<for>, <var>, <groovy>properties.put(....)</groovy>, <property>, <antcallback>) did not work with ANT 1.9.4, so I used the file system similar to this (pseudocode):
<target name="outer">
<for> <antcall target="inner" /> </for>
<loadproperties srcfile="tmpfile.properties" />
<echo message="${outerprop}" />
</target>
<target name="inner">
<!-- did not work: -->
<!--
<property name="outerprop" value="true" />
<var name="outerprop" value="true" />
<groovy>properties.put('outerprop','true')</groovy>
<antcallback target="setouterprop" />
-->
<echo message="outerprop=true" file="tmpfile.properties" />
</target>
Maybe the other approaches did not work because of my <antcall>, but I need it here. (outerprop is initially unset)
I would like to not call a target in build.xml in the case that there is a certain environment variable.
Using Ant 1.7.0, the following code does not work:
<property environment="env"/>
<property name="app.mode" value="${env.APP_MODE}"/>
<target name="someTarget" unless="${app.mode}">
...
</target>
<target name="all" description="Creates app">
<antcall target="someTarget" />
</target>
Target "someTarget" executes whether there is the environment variable APP_MODE or not.
The docs for the unlessattribute say:
the name of the property that must not be set in order for this target to execute, or something evaluating to false
So in your case, you need to put the name of the property, rather than an evaluation of the property:
<target name="someTarget" unless="app.mode">
...
</target>
Notes
In Ant 1.7.1 and earlier, these attributes could only be property names.
As of Ant 1.8.0, you may instead use property expansion; a value of true (or on or yes) will enable the item, while false (or off or no) will disable it.
Other values are still assumed to be property names and so the item is enabled only if the named property is defined.
Reference
if/unless on the ant manual
Unless attribute suggest in simple language that if property is set then the task would not be get executed. for ex.
<target name="clean" unless="clean.not">
<delete dir="${src}" />
<property name="clean.not" value="true" />
<delete dir="${dest}" />
</target>
Here , if you call clean target , it gets executed first then its value is set. And if you want to call it again in script then it would not as property must not be set in order to get the task executed.