112 lines
2.8 KiB
Go
112 lines
2.8 KiB
Go
package pg
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import (
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"context"
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"database/sql"
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"fmt"
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"github.com/hashicorp/terraform/backend"
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"github.com/hashicorp/terraform/helper/schema"
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"github.com/lib/pq"
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)
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const (
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statesTableName = "states"
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statesIndexName = "states_by_name"
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)
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// New creates a new backend for Postgres remote state.
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func New() backend.Backend {
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s := &schema.Backend{
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Schema: map[string]*schema.Schema{
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"conn_str": &schema.Schema{
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Type: schema.TypeString,
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Required: true,
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Description: "Postgres connection string; a `postgres://` URL",
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},
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"schema_name": &schema.Schema{
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Type: schema.TypeString,
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Optional: true,
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Description: "Name of the automatically managed Postgres schema to store state",
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Default: "terraform_remote_state",
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},
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"skip_schema_creation": &schema.Schema{
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Type: schema.TypeBool,
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Optional: true,
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Description: "If set to `true`, Terraform won't try to create the Postgres schema",
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Default: false,
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},
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},
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}
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result := &Backend{Backend: s}
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result.Backend.ConfigureFunc = result.configure
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return result
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}
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type Backend struct {
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*schema.Backend
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// The fields below are set from configure
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db *sql.DB
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configData *schema.ResourceData
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connStr string
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schemaName string
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}
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func (b *Backend) configure(ctx context.Context) error {
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// Grab the resource data
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b.configData = schema.FromContextBackendConfig(ctx)
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data := b.configData
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b.connStr = data.Get("conn_str").(string)
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b.schemaName = pq.QuoteIdentifier(data.Get("schema_name").(string))
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db, err := sql.Open("postgres", b.connStr)
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if err != nil {
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return err
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}
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// Prepare database schema, tables, & indexes.
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var query string
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if !data.Get("skip_schema_creation").(bool) {
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// list all schemas to see if it exists
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var count int
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query = `select count(1) from information_schema.schemata where schema_name = $1`
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if err := db.QueryRow(query, data.Get("schema_name").(string)).Scan(&count); err != nil {
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return err
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}
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// skip schema creation if schema already exists
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// `CREATE SCHEMA IF NOT EXISTS` is to be avoided if ever
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// a user hasn't been granted the `CREATE SCHEMA` privilege
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if count < 1 {
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// tries to create the schema
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query = `CREATE SCHEMA IF NOT EXISTS %s`
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if _, err := db.Exec(fmt.Sprintf(query, b.schemaName)); err != nil {
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return err
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}
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}
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}
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query = `CREATE TABLE IF NOT EXISTS %s.%s (
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id SERIAL PRIMARY KEY,
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name TEXT,
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data TEXT
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)`
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if _, err := db.Exec(fmt.Sprintf(query, b.schemaName, statesTableName)); err != nil {
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return err
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}
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query = `CREATE UNIQUE INDEX IF NOT EXISTS %s ON %s.%s (name)`
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if _, err := db.Exec(fmt.Sprintf(query, statesIndexName, b.schemaName, statesTableName)); err != nil {
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return err
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}
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// Assign db after its schema is prepared.
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b.db = db
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return nil
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}
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