How to invoke a child build definition from powershell using VSTS

Get the buildid(parent and child) of the build defintions and use the powershell script to invoke the build from powershell


$buildQueUri = "$($env:SYSTEM_TEAMFOUNDATIONCOLLECTIONURI)$env:SYSTEM_TEAMPROJECTID/_apis/build/builds?api-version=2.0"


$parameters = @{
"system.debug" = $env:SYSTEM_DEBUG
"deploymentEnvironment" = $deploymentEnvironment
"region" = $regions
"deploymentPaths" =  $deploymentPaths
"parentBuildID" = $buildId
"requestedBy" = $requestedBy
}|ConvertTo-Json -Compress

$body = @{
"definition" = @{ "id" = $childBuildId }
"requestedFor" = @{ "id" = $env:BUILD_REQUESTEDFORID }
"sourceBranch" = $sourceBranch
"sourceVersion" = $sourceVersion
"parameters" = $parameters
}|ConvertTo-Json -Compress

$buildResponse = Invoke-RestMethod -Method Post -Uri $buildQueUri -Headers $headers -Body $body -ContentType 'application/json' -ErrorAction Stop