How can I check if file exists, and if not kill the build?

Question

How can I stop a build, and notify the user if a file does not exist? I know I can use the available task to set a property if a file exists, but I'm not sure how I would stop a build and echo something.

I would like to stick with core tasks if possible.

score 19 · Accepted Answer · edited Jan 04 '11 at 18:42

19

You can use the fail task for all your failing needs. The last example on that page is actually pretty much what you need

<fail message="Files are missing.">
    <condition>
        <not>
            <resourcecount count="2">
                <fileset id="fs" dir="." includes="one.txt,two.txt"/>
            </resourcecount>
        </not>
    </condition>
</fail>

edited Jan 04 '11 at 18:42

martin clayton

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answered Oct 28 '09 at 15:56

stimms

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Amazing how there is always another task that I have never heard about. Thanks. – Steve Oct 28 '09 at 15:58

score 19 · Answer 2 · answered May 25 '14 at 19:06

19

A little simpler (I wish it could be made simpler)

<fail message="file ${myfile} not set or missing">
    <condition>
        <not>
            <available file="${myfile}" />
        </not>
    </condition>
</fail>

answered May 25 '14 at 19:06

leonbloy

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Very clean and easy to understand – Miek Jul 21 '17 at 18:24

score 6 · Answer 3 · edited Jan 04 '11 at 18:41

6

Set your property and use the Fail task with the if attribute.

edited Jan 04 '11 at 18:41

martin clayton

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answered Oct 28 '09 at 15:57

Restore the Data Dumps

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The `if` attribute checks for the *existence* of a property, not its value. – sourcenouveau Jul 24 '13 at 14:43

score 4 · Answer 4 · answered Sep 30 '16 at 17:04

4

This can be done more compactly (as indicated by Jason Punyon). Specifically, assuming the file you want is in the property file, do:

<available file="${file}" property="file.exists" />
<fail message="File missing: ${file}" unless="file.exists" />

answered Sep 30 '16 at 17:04

darrenp

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I think that the unless condition on the fail attribute is much more readable and long term maintainable. – Newteq Developer Nov 09 '17 at 14:50

score 1 · Answer 5 · answered May 30 '18 at 10:56

These kind of checks are common, so it might pay off to use a macro. Here is a macro based on the solution by leonbloy:

<macrodef name="require">
    <attribute name="file"/>
    <attribute name="message" default="file @{file} not set or missing"/>
    <sequential>
        <fail message="@{message}">
            <condition>
            <not>
                <available file="@{file}" />
            </not>
            </condition>
        </fail>
    </sequential>
</macrodef>

Use like this:

<require file="${myfile}" />

or

<require file="${myfile}" message="my custom message" />

How can I check if file exists, and if not kill the build?

5 Answers5

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