Example updating BigQuery view or table descriptions using an M-Lab YAML description file.

main.go

package main

import (
	"context"
	"flag"
	"io/ioutil"

	"cloud.google.com/go/bigquery"

	"github.com/m-lab/go/cloud/bqx"
	"github.com/m-lab/go/flagx"
	"github.com/m-lab/go/rtx"
)

var (
	view    string
	project string
	dataset string
	schemas = flagx.StringArray{}
	ctx     = context.Background()
)

func init() {
	flag.StringVar(&view, "view", "", "name of the view in bigquery")
	flag.StringVar(&project, "project", "", "GCP project")
	flag.StringVar(&dataset, "dataset", "", "Dataset name within project")
	flag.Var(&schemas, "yaml", "Name of yaml description files to merge and apply to named view or table")
}

func main() {
	flag.Parse()

	// Create bigquery client for given project.
	c, err := bigquery.NewClient(ctx, project)
	rtx.Must(err, "failed to get client.")

	// Get reference to view/table and get metadata for it.
	t := c.Dataset(dataset).Table(view)
	md, err := t.Metadata(ctx)
	rtx.Must(err, "failed to read table metadata")

	b, err := ioutil.ReadFile(schemas[0]) // TODO: combine all schema docs.
	rtx.Must(err, "failed to read ")
	doc := bqx.NewSchemaDoc(b)

	// Update the md.Schema in-place using the local docs.
	bqx.UpdateSchemaDescription(md.Schema, doc)

	// Update the original view/table descriptions using the modified schema.
	_, err = t.Update(ctx, bigquery.TableMetadataToUpdate{Schema: md.Schema}, md.ETag)
	rtx.Must(err, "failed to update view schema")
}