func CreateArtifact(req CreateArtifactReq, bucket *model.Bucket, db database.Database) (*model.Artifact, error) {
	if len(req.Name) == 0 {
		return nil, fmt.Errorf("Artifact Name not provided, state = %s", bucket.State)
	}

	if bucket.State != model.OPEN {
		return nil, fmt.Errorf("Bucket is already closed")
	}

	artifact, err := db.GetArtifactByName(bucket.Id, req.Name)
	if err == nil {
		return nil, fmt.Errorf("Artifact already exists")
	}

	artifact = new(model.Artifact)
	artifact.Name = req.Name
	artifact.BucketId = bucket.Id
	artifact.DateCreated = time.Now()

	if req.DeadlineMins == 0 {
		artifact.DeadlineMins = DEFAULT_DEADLINE
	} else {
		artifact.DeadlineMins = req.DeadlineMins
	}

	if req.Chunked {
		artifact.State = model.APPENDING
	} else {
		if req.Size == 0 {
			return nil, fmt.Errorf("Cannot create a new upload artifact without size.")
		}
		artifact.Size = req.Size
		artifact.State = model.WAITING_FOR_UPLOAD
	}
	artifact.Name = req.Name
	if err := db.InsertArtifact(artifact); err != nil {
		return nil, fmt.Errorf("Error inserting artifact %s", err)
	}

	return artifact, nil
}
// CreateArtifact creates a new artifact in a open bucket.
//
// If an artifact with the same name already exists in the same bucket, we attempt to rename the
// artifact by adding a suffix.
// If the request specifies a chunked artifact, the size field is ignored and always set to zero.
// If the request is for a streamed artifact, size is mandatory.
// A relative path field may be specified to preserve the original file name and path. If no path is
// specified, the original artifact name is used by default.
func CreateArtifact(req createArtifactReq, bucket *model.Bucket, db database.Database) (*model.Artifact, *HttpError) {
	if len(req.Name) == 0 {
		return nil, NewHttpError(http.StatusBadRequest, "Artifact name not provided")
	}

	if bucket.State != model.OPEN {
		return nil, NewHttpError(http.StatusBadRequest, "Bucket is already closed")
	}

	artifact := new(model.Artifact)

	artifact.Name = req.Name
	artifact.BucketId = bucket.Id
	artifact.DateCreated = time.Now()

	if req.DeadlineMins == 0 {
		artifact.DeadlineMins = DEFAULT_DEADLINE
	} else {
		artifact.DeadlineMins = req.DeadlineMins
	}

	if req.Chunked {
		artifact.State = model.APPENDING
	} else {
		if req.Size == 0 {
			return nil, NewHttpError(http.StatusBadRequest, "Cannot create a new upload artifact without size.")
		} else if req.Size > MaxArtifactSizeBytes {
			return nil, NewHttpError(http.StatusRequestEntityTooLarge, fmt.Sprintf("Entity '%s' (size %d) is too large (limit %d)", req.Name, req.Size, MaxArtifactSizeBytes))
		}
		artifact.Size = req.Size
		artifact.State = model.WAITING_FOR_UPLOAD
	}

	if req.RelativePath == "" {
		// Use artifact name provided as default relativePath
		artifact.RelativePath = req.Name
	} else {
		artifact.RelativePath = req.RelativePath
	}

	// Attempt to insert artifact and retry with a different name if it fails.
	if err := db.InsertArtifact(artifact); err != nil {
		for attempt := 1; attempt <= MaxDuplicateFileNameResolutionAttempts; attempt++ {
			// Unable to create new artifact - if an artifact already exists, the above insert failed
			// because of a collision.
			if _, err := db.GetArtifactByName(bucket.Id, artifact.Name); err != nil {
				// This could be a transient DB error (down/unreachable), in which case we expect the client
				// to retry. There is no value in attempting alternate artifact names.
				//
				// We have no means of verifying there was a name collision - bail with an internal error.
				return nil, NewHttpError(http.StatusInternalServerError, err.Error())
			}

			// File name collision - attempt to resolve
			artifact.Name = fmt.Sprintf(DuplicateArtifactNameFormat, req.Name, randString(5))
			if err := db.InsertArtifact(artifact); err == nil {
				return artifact, nil
			}
		}

		return nil, NewHttpError(http.StatusInternalServerError, "Exceeded retry limit avoiding duplicates")
	}

	return artifact, nil
}