sql_select
Runs an SQL select query against a database and returns the result as an array of objects, one for each row returned, containing a key for each column queried and its value.
Introduced in version 1.0.0.
- Common
- Advanced
# Common config fields, showing default values
label: ""
sql_select:
driver: "" # No default (required)
dsn: clickhouse://username:password@host1:9000,host2:9000/database?dial_timeout=200ms&max_execution_time=60 # No default (required)
table: foo # No default (required)
columns: [] # No default (required)
where: meow = ? and woof = ? # No default (optional)
args_mapping: root = [ this.cat.meow, this.doc.woofs[0] ] # No default (optional)
# All config fields, showing default values
label: ""
sql_select:
driver: "" # No default (required)
dsn: clickhouse://username:password@host1:9000,host2:9000/database?dial_timeout=200ms&max_execution_time=60 # No default (required)
table: foo # No default (required)
columns: [] # No default (required)
where: meow = ? and woof = ? # No default (optional)
args_mapping: root = [ this.cat.meow, this.doc.woofs[0] ] # No default (optional)
prefix: "" # No default (optional)
suffix: "" # No default (optional)
init_files: [] # No default (optional)
init_statement: | # No default (optional)
CREATE TABLE IF NOT EXISTS some_table (
foo varchar(50) not null,
bar integer,
baz varchar(50),
primary key (foo)
) WITHOUT ROWID;
init_verify_conn: false
conn_max_idle_time: "" # No default (optional)
conn_max_life_time: "" # No default (optional)
conn_max_idle: 2
conn_max_open: 0 # No default (optional)
If the query fails to execute then the message will remain unchanged and the error can be caught using error handling methods outlined here.
Examples
- Table Query (PostgreSQL)
Here we query a database for columns of footable that share a user_id
with the message user.id
. A branch
processor
is used in order to insert the resulting array into the original message at the
path foo_rows
:
pipeline:
processors:
- branch:
processors:
- sql_select:
driver: postgres
dsn: postgres://foouser:foopass@localhost:5432/testdb?sslmode=disable
table: footable
columns: [ '*' ]
where: user_id = ?
args_mapping: '[ this.user.id ]'
result_map: 'root.foo_rows = this'
Fields
driver
A database driver to use.
Type: string
Options: mysql
, postgres
, clickhouse
, mssql
, sqlite
, oracle
, snowflake
, trino
, gocosmos
, spanner
.
dsn
A Data Source Name to identify the target database.
Drivers
The following is a list of supported drivers, their placeholder style, and their respective DSN formats:
Driver | Data Source Name Format |
---|---|
clickhouse | clickhouse://[username[:password]@][netloc][:port]/dbname[?param1=value1&...¶mN=valueN] |
mysql | [username[:password]@][protocol[(address)]]/dbname[?param1=value1&...¶mN=valueN] |
postgres | postgres://[user[:password]@][netloc][:port][/dbname][?param1=value1&...] |
mssql | sqlserver://[user[:password]@][netloc][:port][?database=dbname¶m1=value1&...] |
sqlite | file:/path/to/filename.db[?param&=value1&...] |
oracle | oracle://[username[:password]@][netloc][:port]/service_name?server=server2&server=server3 |
snowflake | username[:password]@account_identifier/dbname/schemaname[?param1=value&...¶mN=valueN] |
spanner | projects/[project]/instances/[instance]/databases/dbname |
trino | http[s]://user[:pass]@host[:port][?parameters] |
gocosmos | AccountEndpoint=<cosmosdb-endpoint>;AccountKey=<cosmosdb-account-key>[;TimeoutMs=<timeout-in-ms>][;Version=<cosmosdb-api-version>][;DefaultDb/Db=<db-name>][;AutoId=<true/false>][;InsecureSkipVerify=<true/false>] |
Please note that the postgres
driver enforces SSL by default, you can override this with the parameter sslmode=disable
if required.
The snowflake
driver supports multiple DSN formats. Please consult the docs for more details. For key pair authentication, the DSN has the following format: <snowflake_user>@<snowflake_account>/<db_name>/<schema_name>?warehouse=<warehouse>&role=<role>&authenticator=snowflake_jwt&privateKey=<base64_url_encoded_private_key>
, where the value for the privateKey
parameter can be constructed from an unencrypted RSA private key file rsa_key.p8
using openssl enc -d -base64 -in rsa_key.p8 | basenc --base64url -w0
(you can use gbasenc
insted of basenc
on OSX if you install coreutils
via Homebrew). If you have a password-encrypted private key, you can decrypt it using openssl pkcs8 -in rsa_key_encrypted.p8 -out rsa_key.p8
. Also, make sure fields such as the username are URL-encoded.
The gocosmos
driver is still experimental, but it has support for hierarchical partition keys as well as cross-partition queries. Please refer to the SQL notes for details.
Type: string
# Examples
dsn: clickhouse://username:password@host1:9000,host2:9000/database?dial_timeout=200ms&max_execution_time=60
dsn: foouser:foopassword@tcp(localhost:3306)/foodb
dsn: postgres://foouser:foopass@localhost:5432/foodb?sslmode=disable
dsn: oracle://foouser:foopass@localhost:1521/service_name
table
The table to query.
Type: string
# Examples
table: foo
columns
A list of columns to query.
Type: array
# Examples
columns:
- '*'
columns:
- foo
- bar
- baz
where
An optional where clause to add. Placeholder arguments are populated with the args_mapping
field. Placeholders should always be question marks, and will automatically be converted to dollar syntax when the postgres or clickhouse drivers are used.
Type: string
# Examples
where: meow = ? and woof = ?
where: user_id = ?
args_mapping
An optional Bloblang mapping which should evaluate to an array of values matching in size to the number of placeholder arguments in the field where
.
Type: string
# Examples
args_mapping: root = [ this.cat.meow, this.doc.woofs[0] ]
args_mapping: root = [ meta("user.id") ]
prefix
An optional prefix to prepend to the query (before SELECT).
Type: string
suffix
An optional suffix to append to the select query.
Type: string
init_files
An optional list of file paths containing SQL statements to execute immediately upon the first connection to the target database. This is a useful way to initialise tables before processing data. Glob patterns are supported, including super globs (double star).
Care should be taken to ensure that the statements are idempotent, and therefore would not cause issues when run multiple times after service restarts. If both init_statement
and init_files
are specified the init_statement
is executed after the init_files
.
If a statement fails for any reason a warning log will be emitted but the operation of this component will not be stopped.
Type: array
Requires version 1.0.0 or newer
# Examples
init_files:
- ./init/*.sql
init_files:
- ./foo.sql
- ./bar.sql
init_statement
An optional SQL statement to execute immediately upon the first connection to the target database. This is a useful way to initialise tables before processing data. Care should be taken to ensure that the statement is idempotent, and therefore would not cause issues when run multiple times after service restarts.
If both init_statement
and init_files
are specified the init_statement
is executed after the init_files
.
If the statement fails for any reason a warning log will be emitted but the operation of this component will not be stopped.
Type: string
Requires version 1.0.0 or newer
# Examples
init_statement: |2
CREATE TABLE IF NOT EXISTS some_table (
foo varchar(50) not null,
bar integer,
baz varchar(50),
primary key (foo)
) WITHOUT ROWID;
init_verify_conn
Whether to verify the database connection on startup by performing a simple ping, by default this is disabled.
Type: bool
Default: false
Requires version 1.2.0 or newer
conn_max_idle_time
An optional maximum amount of time a connection may be idle. Expired connections may be closed lazily before reuse. If value <= 0
, connections are not closed due to a connections idle time.
Type: string
conn_max_life_time
An optional maximum amount of time a connection may be reused. Expired connections may be closed lazily before reuse. If value <= 0
, connections are not closed due to a connections age.
Type: string
conn_max_idle
An optional maximum number of connections in the idle connection pool. If conn_max_open is greater than 0 but less than the new conn_max_idle, then the new conn_max_idle will be reduced to match the conn_max_open limit. If value <= 0
, no idle connections are retained. The default max idle connections is currently 2. This may change in a future release.
Type: int
Default: 2
conn_max_open
An optional maximum number of open connections to the database. If conn_max_idle is greater than 0 and the new conn_max_open is less than conn_max_idle, then conn_max_idle will be reduced to match the new conn_max_open limit. If value <= 0
, then there is no limit on the number of open connections. The default is 0 (unlimited).
Type: int