StartBuildWaitForLogEntries.ps1

$token="<Your_api_token>"
$accountName="<Your_account>"
$projectSlug="<Your_project_slug>"
$toFind = @("foo", "bar")

$headers = @{
  "Authorization" = "Bearer $token"
  "Content-type" = "application/json"
}

$body = @{
    accountName=$accountName
    projectSlug=$projectSlug
}

$body = $body | ConvertTo-Json

$newBuild = Invoke-RestMethod -Uri 'https://ci.appveyor.com/api/builds' -Headers $headers  -Body $body -Method POST
$jobId = (Invoke-RestMethod -Uri "https://ci.appveyor.com/api/projects/$accountName/$projectSlug/build/$($newBuild.version)" -Headers $headers  -Method GET).build.jobs[0].jobId

$status = "running";
$found = $false
while(($status -eq "running") -and ($found -eq $false)) {
  try {$log = Invoke-RestMethod -Uri "https://ci.appveyor.com/api/buildjobs/$jobId/log" -Headers $headers  -Method GET} catch {}
  if ($log) {
    $found = $true
    $toFind | % {if(!$log.Contains($_)) {$found = $false}} 
    $status = (Invoke-RestMethod -Uri "https://ci.appveyor.com/api/projects/$accountName/$projectSlug/build/$($newBuild.version)" -Headers $headers  -Method GET).build.status    
    write-host "Status: $status"
    write-host "Found: $found"
    if ($found) { $toFind | % {$log | findstr /psi $_}}
  }
  sleep 1
}