TFS API: Clone Build Definition Environment - powershell

Question

I want to clone an existing environment within a build definition.
This is possible through the TFS GUI, but it doesn't seem like the API natively supports it.
So far, I've tried the following (in PowerShell):
Download build definition and deserialize
[void][System.Reflection.Assembly]::LoadFile("$pwd\Newtonsoft.Json.dll")
$TargetDefinitionName = "Name"
$TargetDefinitionID = ($DefinitionsOverview | Where-Object { $_.name -eq $TargetDefinitionName } | Select-Object -First 1).id
$TargetDefinitionURL = "$TfsUri/$TargetDefinitionID"
$TargetDefinitionJSON = Invoke-WebRequest -Uri "$TargetDefinitionURL" -UseDefaultCredentials
$DeserializedBuildDefinition = [Newtonsoft.Json.JsonConvert]::DeserializeObject($TargetDefinitionJSON.Content)
$DeserializedBuildDefinition.ToString()
Duplicate JSON block that represents environment, change unique properties
$NewEnvironmentString = $DeserializedBuildDefinition.environments[4].ToString()
$DeserializedBuildDefinition.environments.Add(5)
$DeserializedBuildDefinition.environments[5] = $NewEnvironmentString
$DeserializedBuildDefinition.environments[5].name.value = "NewEnvironment"
$DeserializedBuildDefinition.environments[5].rank.value = "6"
$DeserializedBuildDefinition.environments[5].id.value = "1665"
$DeserializedBuildDefinition.revision.value = "20"
Serialize JSON and post back (with new environment)
$SerializedBuildDefinition = [Newtonsoft.Json.JsonConvert]::SerializeObject($DeserializedBuildDefinition)
$PostData = [System.Text.Encoding]::UTF8.GetBytes($SerializedBuildDefinition)
$Headers = #{ "Accept" = "api-version=2.0-preview" }
$Response = Invoke-WebRequest -UseDefaultCredentials -Uri
$TargetDefinitionURL -Headers $Headers `
-Method Put -Body $PostData -ContentType "application/json"
$Response.StatusDescription
PROBLEM: $Response.StatusDescription gives "OK," but no new environment appears in the build definition.
One thought is that, in addition to 'name,' 'ID,' and 'rank, there are other values that need to be unique per environment that I'm missing.
I've also tried cloning the environment manually, saving the JSON representation of the definition, deleting the environment, and posting the JSON back. The new environment still doesn't show up.
Any help would be appreciated.

Answer 1

Future: Yaml based build definitions as code are well on their way, at least to VSTS. This won't help an immediate need but probably offers a better and more lightweight future approach.

Answer 2

When you copy an environment, you need to change "id", "name", and "rank". And the “id” need to be changed to "0". Also, try to use api-version=2.3-preview.1.
Then use the api of update a release definition to update the definition:
PUT http://tfs2015:8080/tfs/teamprojectcollection/teamProject/_apis/release/definitions?api-version=2.3-preview.1
{
……
}
I have tested with TFS 2015 Update 4. Api could clone an environment successfully.

Answer 3

I created a tool for cloning TFS builds, as (with TFS 2015 update 1 at least) the web 'clone' function does not clone the 'Repository' or 'Triggers' tab. Some of our build steps were a little complicated so I also wrote some simple transforms to automatically set the values according to the target branch.
I used the BuildHttpClient object in Microsoft.TeamFoundation.Build2.WebApi assembly to get the original build definition (BuildDefinition object, using GetDefinitionAsync() method), transform any build steps values, then call CreateDefinitionAsync() on BuildHttpClient to create the new build.
Works very reliably and under the hood it appears to use the TFS REST API.
If there was any interest, I'd be happy to create a more in depth tutorial on this.