# triggers

Tag: triggers

[since 1.4]

Defines a list of triggers to activate on some Ivy events.

A trigger is an action which is performed whenever a particular event occurs. Ivy supports 3 type of triggers out of the box:

- ant-call
  calls a target in the same build as the original one whenever a particular event occurs.

- ant-build
  calls an Ant build which may be in another Ant build script.

- log
  echo a message, usually in a file

If you want to use a different trigger, you can implement your own.

The following events are available in Ivy:

Name | Attributes | Description
--- | --- | ---

pre-resolve

* organisation
the organisation of the module for which the dependencies will be resolved

* module
the name of the module for which the dependencies will be resolved

* revision
the revision of the module for which the dependencies will be resolved

* conf
comma separated list of configurations which will be resolved

Fired at the beginning of the resolve process, before module dependencies and transitive dependencies are resolved.

pre-resolve-dependency

* organisation
the organisation of the dependency resolved

* module
the name of the dependency resolved

* req-revision
the requested revision for the dependency (since 2.0) (provided for consistency with post-resolve-dependency)

* req-revision-default
the default requested revision constraint for the dependency (since 2.0)

* req-revision-dynamic
the requested revision dynamic constraint for the dependency (since 2.0)

* revision
the requested revision for the dependency

* resolver
the name of the resolver used to resolve the dependency

Fired before each dependency is resolved. In this case resolved means resolving the actual revision if the requested revision is a version constraint and not a static version, and downloading all necessary metadata information.

post-resolve-dependency

* organisation
the organisation of the dependency resolved

* module
the name of the dependency resolved

* req-revision
the requested revision for the dependency (since 2.0)

* req-revision-default
the default requested revision constraint for the dependency (since 2.0)

* req-revision-dynamic
the requested revision dynamic constraint for the dependency (since 2.0)

* revision
the revision of the dependency resolved, or the requested revision if the resolution was not successful

* resolved
true if the resolution was successful, false otherwise

* duration
the time elapsed to resolve the dependency (in ms) (since 2.0)

* resolver
the name of the resolver used to resolve the dependency

* any extra attribute
all extra attributes found on the info tag of the resolved dependency are available (since 2.0)

Fired after each dependency is resolved

post-resolve

* organisation
the organisation of the module for which the dependencies have been resolved

* module
the name of the module for which the dependencies have been resolved

* revision
the revision of the module for which the dependencies have been resolved

* conf
comma separated list of configurations resolved

* resolve-id
the identifier of the resolution process (since 2.0)

* nb-dependencies
total number of dependencies, including transitive and evicted ones (since 2.0)

* nb-artifacts
total number of artifacts resolved, excluding metadata artifacts (since 2.0)

* resolve-duration
the time (in ms) elapsed to resolve dependencies, before downloading artifacts (since 2.0)

* download-duration
the time (in ms) elapsed to download all artifacts, excluding metadata artifacts downloaded during the first phase of the resolution process (since 2.0)

* download-size
the total size (in bytes) of all downloaded artifacts, excluding metadata artifacts. Only artifacts actually downloaded (not in cache or used from their original location) are considered (since 2.0)

Fired at the end of the resolve process, when all module dependencies have been resolved

pre-download-artifact

* organisation
the organisation of the artifact which is about to be downloaded

* module
the name of the module of the artifact which is about to be downloaded

* revision
the revision of the the artifact which is about to be downloaded

* artifact
the name of the the artifact which is about to be downloaded

* type
the type of the the artifact which is about to be downloaded

* ext
the extension of the the artifact which is about to be downloaded

* metadata
true if the artifact to be downloaded is a metadata artifact, false for published artifacts (since 2.0)

* resolver
the name of the resolver used to download the artifact

* origin
the origin location from which it will be downloaded

* local
true if it’s a local artifact, false otherwise

Fired before an artifact is downloaded from a repository to the cache

post-download-artifact

* organisation
the organisation of the artifact which was just downloaded

* module
the name of the module of the artifact which was just downloaded

* revision
the revision of the the artifact which was just downloaded

* artifact
the name of the the artifact which was just downloaded

* type
the type of the the artifact which was just downloaded

* ext
the extension of the the artifact which was just downloaded

* metadata
true if the downloaded artifact is a metadata artifact, false for published artifacts (since 2.0)

* resolver
the name of the resolver used to download the artifact

* origin
the origin location from which it was downloaded

* local
true if it’s a local artifact, false otherwise

* size
the size in bytes of the downloaded artifact

* duration
the time elapsed to download the artifact (in ms) (since 2.0)

* file
the file to which it has been downloaded

Fired after an artifact has been downloaded from a repository to the cache

pre-retrieve (since 2.0)

* organisation
the organisation of the module for which the dependencies will be retrieved

* module
the name of the module for which the dependencies will be retrieved

* revision
the revision of the module for which the dependencies will be retrieved

* conf
comma separated list of configurations which will be retrieved

* symlink
true if Ivy will use symbolic links instead of copies on supported platforms, false otherwise

* sync
true if the retrieve process will be performed in sync mode, false otherwise

Fired at the beginning of the retrieve process.

post-retrieve (since 2.0)

* organisation
the organisation of the module for which the dependencies have been retrieved

* module
the name of the module for which the dependencies will be retrieved

* revision
the revision of the module for which the dependencies have been retrieved

* conf
comma separated list of configurations which have been retrieved

* symlink
true if Ivy used symbolic links instead of copies on supported platforms, false otherwise

* sync
true if the retrieve process has been performed in sync mode, false otherwise

* duration
the time elapsed in ms during the retrieve process

* size
the total size of artifacts which have actually been copied (or symlinked)

* nbCopied
the number of artifacts copied or symlinked

* nbUptodate
the number of artifacts which were already present and up to date at the destination location

Fired at the end of the retrieve process.

pre-retrieve-artifact (since 2.1)

* organisation
the organisation of the artifact which is about to be retrieved

* module
the name of the module of the artifact which is about to be retrieved

* revision
the revision of the the artifact which is about to be retrieved

* artifact
the name of the the artifact which is about to be retrieved

* type
the type of the the artifact which is about to be retrieved

* ext
the extension of the the artifact which is about to be retrieved

* metadata
true if the retrieved artifact is a metadata artifact, false for published artifacts

* size
the size in bytes of the retrieved artifact

* from
the absolute path from which it will be retrieved (usually a location in cache)

* to
the absolute path to which it will be retrieved

Fired before an artifact is retrieved from the cache to a local location

post-retrieve-artifact (since 2.1)

* organisation
the organisation of the artifact which has just been retrieved

* module
the name of the module of the artifact which has just been retrieved

* revision
the revision of the the artifact which has just been retrieved

* artifact
the name of the the artifact which has just been retrieved

* type
the type of the the artifact which has just been retrieved

* ext
the extension of the the artifact which has just been retrieved

* metadata
true if the retrieved artifact is a metadata artifact, false for published artifacts

* size
the size in bytes of the retrieved artifact

* from
the absolute path from which it has just been retrieved (usually a location in cache)

* to
the absolute path to which it has just been retrieved

Fired after an artifact is retrieved from the cache to a local location

pre-publish-artifact (since 2.0)

* organisation
the organisation of the artifact which is about to be published

* module
the name of the module of the artifact which is about to be published

* revision
the revision of the the artifact which is about to be published

* artifact
the name of the the artifact which is about to be published

* type
the type of the the artifact which is about to be published

* ext
the extension of the the artifact which is about to be published

* resolver
the name of the resolver into which the artifact is about to be published

* file
the absolute path of the source file for the artifact

* overwrite
"true" if the new data will overwrite existing artifacts, "false" otherwise

Fired before an artifact is published into a repository

post-publish-artifact (since 2.0)

* organisation
the organisation of the artifact that was published

* module
the name of the module of the artifact that was published

* revision
the revision of the the artifact that was published

* artifact
the name of the the artifact that was published

* type
the type of the the artifact that was published

* ext
the extension of the the artifact that was published

* resolver
the name of the resolver into which the artifact was published

* file
the absolute path of the source file for the artifact

* overwrite
"true" if the new data overwrote existing artifacts, "false" otherwise

* status
"successful" if the artifact published successfully; "failed" if the artifact failed to publish, or if the status is unknown

Fired after an artifact is published into a repository. Note that this event is fired whether or not the publication succeeded. The "status" property can be checked to verify success.

The child tag used for the dependency resolver must be equal to a name of a trigger type (either built-in or added with the `typedef` tag).

## Child elements

Element | Description | Cardinality
--- | --- | ---
any trigger | adds a trigger to the list of registered triggers | 1..n

## Built-in Triggers

Ivy comes with 3 built-in triggers:

Name | Description
--- | ---
ant-build | Triggers an Ant build. Note that by default the Ant build is triggered only once per build file, the property onlyonce can be set to false to change this.
ant-call | Calls a target in the current Ant build.
log | Logs a message on the console or in a log file.

## Common attributes

All triggers share some common attributes detailed here.

Among these attributes, you will find how to select when the trigger should be performed. You have to provide an event name, which is simple, but you can also use a filter expression. The syntax for this expression is very simple and limited:

- you can use the = operator to compare an attribute (left operand) with a value (right operand).

- you can use AND OR NOT as boolean operators

- you cannot use parenthesis to change the precedence

Attribute | Description | Required
--- | --- | ---
name | the name of the trigger for identification purpose only | Yes
event | the name of the event on which the trigger should be performed | Yes
filter | a filter expression used to restrict when the trigger should be performed | No, defaults to no filter

## Examples

    <triggers>
        <ant-build antfile="${ivy.settings.dir}/[module]/build.xml" target="publish"
               event="pre-resolve-dependency" filter="revision=latest.integration"/>
    </triggers>

Triggers an Ant build of the Ant file `${ivy.settings.dir}/[module]/build.xml` (where `[module]` is replaced by the name of the dependency resolved) with the target "publish", just before resolving a dependency with a `latest.integration` revision. Note that by default the Ant build is triggered only once per build file. See below to see how to trigger the build more than once.

    <triggers>
        <ant-build antfile="${ivy.settings.dir}/[module]/build.xml" target="publish"
               event="pre-resolve-dependency" filter="revision=latest.integration"
               onlyonce="false"/>
    </triggers>

Same as before, but this time the builds will be triggered as many time as the dependency is resolved, instead of only once.

    <triggers>
        <ant-call target="unzip" prefix="dep"
              event="post-download-artifact" filter="type=zip AND status=successful"/>
    </triggers>

Triggers an Ant call of the target unzip just after downloading a zip artifact, prefixing all parameters to the target with `dep`. Here is how the target can look like:

    <target name="unzip">
         <echo>
            unzipping artifact:
            organisation=${dep.organisation}
            module=${dep.module}
            revision=${dep.revision}
            artifact=${dep.artifact}
            type=${dep.type}
            ext=${dep.ext}
            origin=${dep.origin}
            local=${dep.local}
            size=${dep.size}
            file=${dep.file}
         </echo>
         <mkdir dir="${basedir}/out"/>
         <unzip src="${dep.file}" dest="${basedir}/out"/>
    </target>

    <triggers>
        <log file="ivy.log"
              message='downloaded "${origin}" to "${file}" (${duration}ms - ${size}B)'
              event="post-download-artifact" filter="status=successful"/>
    </triggers>

Logs any successful artifact download, with information on the source and destination, and details on download size and duration.

The `file` attribute is optional, the log trigger will output messages to console if it isn’t provided.