Lua Scripting

Lua Scripting

New in version Pacific.

Contents

Lua Scripting

This feature allows users to upload Lua scripts to different context in the radosgw. The two supported context are “preRequest” that will execute a script before the operation was taken, and “postRequest” that will execute after each operation is taken. Script may be uploaded to address requests for users of a specific tenant. The script can access fields in the request and modify some fields. All Lua language features can be used in the script.

Script Management via CLI

To upload a script:

# radosgw-admin script put --infile={lua-file} --context={preRequest|postRequest} [--tenant={tenant-name}]

To print the content of the script to standard output:

# radosgw-admin script get --context={preRequest|postRequest} [--tenant={tenant-name}]

To remove the script:

# radosgw-admin script rm --context={preRequest|postRequest} [--tenant={tenant-name}]

Context Free Functions

Debug Log

The RGWDebugLog() function accepts a string and prints it to the debug log with priority 20. Each log message is prefixed Lua INFO:. This function has no return value.

Request Fields

Warning

This feature is experimental. Fields may be removed or renamed in the future.

Note

Although Lua is a case-sensitive language, field names provided by the radosgw are case-insensitive. Function names remain case-sensitive.
Fields marked “optional” can have a nil value.
Fields marked as “iterable” can be used by the pairs() function and with the # length operator.
All table fields can be used with the bracket operator [].
time fields are strings with the following format: %Y-%m-%d %H:%M:%S.

Field	Type	Description	Iterable	Writeable	Optional
`Request.RGWOp`	string	radosgw operation	no	no	no
`Request.DecodedURI`	string	decoded URI	no	no	no
`Request.ContentLength`	integer	size of the request	no	no	no
`Request.GenericAttributes`	table	string to string generic attributes map	yes	no	no
`Request.Response`	table	response to the request	no	no	no
`Request.Response.HTTPStatusCode`	integer	HTTP status code	no	yes	no
`Request.Response.HTTPStatus`	string	HTTP status text	no	yes	no
`Request.Response.RGWCode`	integer	radosgw error code	no	yes	no
`Request.Response.Message`	string	response message	no	yes	no
`Request.SwiftAccountName`	string	swift account name	no	no	yes
`Request.Bucket`	table	info on the bucket	no	no	yes
`Request.Bucket.Tenant`	string	tenant of the bucket	no	no	no
`Request.Bucket.Name`	string	bucket name	no	no	no
`Request.Bucket.Marker`	string	bucket marker (initial id)	no	no	no
`Request.Bucket.Id`	string	bucket id	no	no	no
`Request.Bucket.Count`	integer	number of objects in the bucket	no	no	no
`Request.Bucket.Size`	integer	total size of objects in the bucket	no	no	no
`Request.Bucket.ZoneGroupId`	string	zone group of the bucket	no	no	no
`Request.Bucket.CreationTime`	time	creation time of the bucket	no	no	no
`Request.Bucket.MTime`	time	modification time of the bucket	no	no	no
`Request.Bucket.Quota`	table	bucket quota	no	no	no
`Request.Bucket.Quota.MaxSize`	integer	bucket quota max size	no	no	no
`Request.Bucket.Quota.MaxObjects`	integer	bucket quota max number of objects	no	no	no
`Reques.Bucket.Quota.Enabled`	boolean	bucket quota is enabled	no	no	no
`Request.Bucket.Quota.Rounded`	boolean	bucket quota is rounded to 4K	no	no	no
`Request.Bucket.PlacementRule`	table	bucket placement rule	no	no	no
`Request.Bucket.PlacementRule.Name`	string	bucket placement rule name	no	no	no
`Request.Bucket.PlacementRule.StorageClass`	string	bucket placement rule storage class	no	no	no
`Request.Bucket.User`	table	bucket owner	no	no	no
`Request.Bucket.User.Tenant`	string	bucket owner tenant	no	no	no
`Request.Bucket.User.Id`	string	bucket owner id	no	no	no
`Request.Object`	table	info on the object	no	no	yes
`Request.Object.Name`	string	object name	no	no	no
`Request.Object.Instance`	string	object version	no	no	no
`Request.Object.Id`	string	object id	no	no	no
`Request.Object.Size`	integer	object size	no	no	no
`Request.Object.MTime`	time	object mtime	no	no	no
`Request.CopyFrom`	table	information on copy operation	no	no	yes
`Request.CopyFrom.Tenant`	string	tenant of the object copied from	no	no	no
`Request.CopyFrom.Bucket`	string	bucket of the object copied from	no	no	no
`Request.CopyFrom.Object`	table	object copied from. See: `Request.Object`	no	no	yes
`Request.ObjectOwner`	table	object owner	no	no	no
`Request.ObjectOwner.DisplayName`	string	object owner display name	no	no	no
`Request.ObjectOwner.User`	table	object user. See: `Request.Bucket.User`	no	no	no
`Request.ZoneGroup.Name`	string	name of zone group	no	no	no
`Request.ZoneGroup.Endpoint`	string	endpoint of zone group	no	no	no
`Request.UserAcl`	table	user ACL	no	no	no
`Request.UserAcl.Owner`	table	user ACL owner. See: `Request.ObjectOwner`	no	no	no
`Request.UserAcl.Grants`	table	user ACL map of string to grant note: grants without an Id are not presented when iterated and only one of them can be accessed via brackets	yes	no	no
`Request.UserAcl.Grants[“<name>”]`	table	user ACL grant	no	no	no
`Request.UserAcl.Grants[“<name>”].Type`	integer	user ACL grant type	no	no	no
`Request.UserAcl.Grants[“<name>”].User`	table	user ACL grant user	no	no	no
`Request.UserAcl.Grants[“<name>”].User.Tenant`	table	user ACL grant user tenant	no	no	no
`Request.UserAcl.Grants[“<name>”].User.Id`	table	user ACL grant user id	no	no	no
`Request.UserAcl.Grants[“<name>”].GroupType`	integer	user ACL grant group type	no	no	no
`Request.UserAcl.Grants[“<name>”].Referer`	string	user ACL grant referer	no	no	no
`Request.BucketAcl`	table	bucket ACL. See: `Request.UserAcl`	no	no	no
`Request.ObjectAcl`	table	object ACL. See: `Request.UserAcl`	no	no	no
`Request.Environment`	table	string to string environment map	yes	no	no
`Request.Policy`	table	policy	no	no	yes
`Request.Policy.Text`	string	policy text	no	no	no
`Request.Policy.Id`	string	policy Id	no	no	yes
`Request.Policy.Statements`	table	list of string statements	yes	no	no
`Request.UserPolicies`	table	list of user policies	yes	no	no
`Request.UserPolicies[<index>]`	table	user policy. See: `Request.Policy`	no	no	no
`Request.RGWId`	string	radosgw host id: `<host>-<zone>-<zonegroup>`	no	no	no
`Request.HTTP`	table	HTTP header	no	no	no
`Request.HTTP.Parameters`	table	string to string parameter map	yes	no	no
`Request.HTTP.Resources`	table	string to string resource map	yes	no	no
`Request.HTTP.Metadata`	table	string to string metadata map	yes	yes	no
`Request.HTTP.Host`	string	host name	no	no	no
`Request.HTTP.Method`	string	HTTP method	no	no	no
`Request.HTTP.URI`	string	URI	no	no	no
`Request.HTTP.QueryString`	string	HTTP query string	no	no	no
`Request.HTTP.Domain`	string	domain name	no	no	no
`Request.Time`	time	request time	no	no	no
`Request.Dialect`	string	“S3” or “Swift”	no	no	no
`Request.Id`	string	request Id	no	no	no
`Request.TransactionId`	string	transaction Id	no	no	no
`Request.Tags`	table	object tags map	yes	no	no

Print information on source and destination objects in case of copy:

function print_object(object)
  RGWDebugLog("  Name: " .. object.Name)
  RGWDebugLog("  Instance: " .. object.Instance)
  RGWDebugLog("  Id: " .. object.Id)
  RGWDebugLog("  Size: " .. object.Size)
  RGWDebugLog("  MTime: " .. object.MTime)
end
if Request.CopyFrom and Request.Object and Request.CopyFrom.Object then
  RGWDebugLog("copy from object:")
  print_object(Request.CopyFrom.Object)
  RGWDebugLog("to object:")
  print_object(Request.Object)
end

Print ACLs via a “generic function”:

function print_owner(owner)
  RGWDebugLog("Owner:")
  RGWDebugLog("  Dispaly Name: " .. owner.DisplayName)
  RGWDebugLog("  Id: " .. owner.User.Id)
  RGWDebugLog("  Tenanet: " .. owner.User.Tenant)
end
function print_acl(acl_type)
  index = acl_type .. "ACL"
  acl = Request[index]
  if acl then
    RGWDebugLog(acl_type .. "ACL Owner")
    print_owner(acl.Owner)
    RGWDebugLog("  there are " .. #acl.Grants .. " grant for owner")
    for k,v in pairs(acl.Grants) do
      RGWDebugLog("    Grant Key: " .. k)
      RGWDebugLog("    Grant Type: " .. v.Type)
      RGWDebugLog("    Grant Group Type: " .. v.GroupType)
      RGWDebugLog("    Grant Referer: " .. v.Referer)
      RGWDebugLog("    Grant User Tenant: " .. v.User.Tenant)
      RGWDebugLog("    Grant User Id: " .. v.User.Id)
    end
  else
    RGWDebugLog("no " .. acl_type .. " ACL in request: " .. Request.Id)
  end
end
print_acl("User")
print_acl("Bucket")
print_acl("Object")

Use of operations log only in case of errors:

if Request.Response.HTTPStatusCode ~= 200 then
  RGWDebugLog("request is bad, use ops log")
  rc = Request.Log()
  RGWDebugLog("ops log return code: " .. rc)
end

Set values into the error message:

if Request.Response.HTTPStatusCode == 500 then
  Request.Response.Message = "<Message> something bad happened :-( </Message>"
end

Add metadata to objects that was not originally sent by the client:

In the preRequest context we should add:

if Request.RGWOp == 'put_obj' then
  Request.HTTP.Metadata["x-amz-meta-mydata"] = "my value"
end

In the postRequest context we look at the metadata:

RGWDebugLog("number of metadata entries is: " .. #Request.HTTP.Metadata)
for k, v in pairs(Request.HTTP.Metadata) do
  RGWDebugLog("key=" .. k .. ", " .. "value=" .. v)
end

Lua Scripting

Lua Scripting

Script Management via CLI

Context Free Functions

Debug Log

Request Fields

Request Functions

Operations Log

Lua Code Samples