It is simply the best/simplest solution and trying to prevent users from passing and integer here would be like opening a can of worms. Because:
* we cannot make mapstructure validate our duration string ( with an UnmarshalJSON func etc.)
* we cannot make mapstructure spit a string instead of a duration and packer will decode-encode-decode config.
* the hcl2 generated code asks for a string, so this will be enforced by default.
Before this commit it was possible to set a duration using an integer or a float. Go's time.Duration is an int64 internally an mapstructure will take advantage of this and load the number as a int64 but `1` means one ns which is unexpected/confusing. To avoid confusion and enforce readability this forces users to pass a string with a unit for a duration; ex "56s".
Run now takes a context as well as a statebag. We'll assign the context
to the blank identifier to prevent namespace collisions. We'll let the
step authors opt-in to using the context.
`find . -iname "step_*.go" -exec gsed -i'' 's/func \(.*\)Run(/func \1Run(_ context.Context, /' {} \;`
- Startup scripts can be provided through the instance creation metadata field 'startup-script'.
- Script log can be copied to a GCS location by setting the metadata field 'startup-script-log-dest'.
Added Retry method to googlecompute package.
Added GetSerialPortOutput to googlecompute Drivers.
Added StepWaitInstanceStartup (and associated test) which waits for an
instance startup-script to finish.
Changed the instance service account to use the same service account as the one provided in the Packer config template. It was the project default service account.
Tested googlecompute package with 'go test' and also performed builds
with a startup script and without a startup script.
The new flow:
1) Provision the instance
2) Tear down the instance, but keep the boot disk
3) Create an image from the disk
4) Tear down the disk
The step to update gcloud is no longer needed, since gceimagebundle isn't used anymore.
Fixes#1507 and addresses https://github.com/mitchellh/packer/issues/1447#issuecomment-61610235.