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Cloud SQL Proxy

The Cloud SQL Proxy allows a user with the appropriate permissions to connect to a Second Generation Cloud SQL database without having to deal with IP whitelisting or SSL certificates manually. It works by opening unix/tcp sockets on the local machine and proxying connections to the associated Cloud SQL instances when the sockets are used.

To build from source, ensure you have go installed and have set GOPATH. Then, simply do a go get:

go get

The cloud_sql_proxy will be placed in $GOPATH/bin after go get completes.

cloud_sql_proxy takes a few arguments to configure what instances to connect to and connection behavior:

  • -fuse: requires access to /dev/fuse as well as the fusermount binary. An optional -fuse_tmp flag can specify where to place temporary files. The directory indicated by -dir is mounted.
  • -instances="project1:region:instance1,project3:region:instance1": A comma-separated list of instances to open inside -dir. Also supports exposing a tcp port and renaming the default Unix Domain Sockets; see examples below. Same list can be provided via INSTANCES environment variable, in case when both are provided - proxy will use command line flag.
  • -instances_metadata=metadata_key: Usable on GCE only. The given GCE metadata key will be polled for a list of instances to open in -dir. The metadata key is relative from computeMetadata/v1/. The format for the value is the same as the 'instances' flag. A hanging-poll strategy is used, meaning that changes to the metadata value will be reflected in the -dir even while the proxy is running. When an instance is removed from the list the corresponding socket will be removed from -dir as well (unless it was also specified in -instances), but any existing connections to this instance will NOT be terminated.
  • -ip_address_types=PUBLIC,PRIVATE: A comma-delimited list of preferred IP types for connecting to an instance. For example, setting this to PRIVATE will force the proxy to connect to instances using an instance's associated private IP. Defaults to PUBLIC,PRIVATE
  • -term_timeout=30s: How long to wait for connections to close before shutting down the proxy. Defaults to 0.
  • -skip_failed_instance_config: Setting this flag will allow you to prevent the proxy from terminating when some instance configurations could not be parsed and/or are unavailable.

Note: -instances and -instances_metadata may be used at the same time but are not compatible with the -fuse flag.

cloud_sql_proxy authentication can be configured in a few different ways. Those listed higher on the list will override options lower on the list:

  1. credential_file flag

  2. token flag

  3. Service account key at path stored in GOOGLE_APPLICATION_CREDENTIALS

  4. gcloud user credentials (set from gcloud auth login)

  5. Default Application Credentials via goauth:

    2. gcloud application default credentials (set from gcloud auth application-default login)
    3. appengine.AccessToken (for App Engine Go < =1.9)
    4. GCE/GAE metadata credentials

When the proxy authenticates under the default service account of the Compute Engine VM it is running on the VM must have at least the sqlservice.admin API scope ("") and the associated project must have the SQL Admin API enabled. The default service account must also have at least WRITER/EDITOR priviledges to any projects of target SQL instances.

Specifying the -credential_file flag allows use of the proxy outside of Google's cloud. Simply create a new service account, download the associated JSON file, and set -credential_file to the path of the JSON file. You can also set the GOOGLE_APPLICATION_CREDENTIALS environment variable instead of passing this flag.

Example invocations:

./cloud_sql_proxy -dir=/cloudsql -instances=my-project:us-central1:sql-inst &
mysql -u root -S /cloudsql/my-project:us-central1:sql-inst

# To retrieve instances from a custom metadata value (only when running on GCE)
./cloud_sql_proxy -dir=/cloudsql -instances_metadata instance/attributes/<custom-metadata-key> &
mysql -u root -S /cloudsql/my-project:us-central1:sql-inst

# For -fuse you do not need to specify instance names ahead of time:
./cloud_sql_proxy -dir=/cloudsql -fuse &
mysql -u root -S /cloudsql/my-project:us-central1:sql-inst

# For programs which do not support using Unix Domain Sockets, specify tcp:
./cloud_sql_proxy -dir=/cloudsql -instances=my-project:us-central1:sql-inst=tcp:3306 &
mysql -u root -h

# For programs which require a certain Unix Domain Socket name:
./cloud_sql_proxy -dir=/cloudsql -instances=my-project:us-central1:sql-inst=unix:custom_socket_name &
mysql -u root -S /cloudsql/custom_socket_name

# For programs which require a the Unix Domain Socket at a specific location, set an absolute path (overrides -dir):
./cloud_sql_proxy -dir=/cloudsql -instances=my-project:us-central1:sql-inst=unix:/my/custom/sql-socket &
mysql -u root -S /my/custom/sql-socket

Container Images

For convenience, we currently host containerized versions of the proxy in the following GCR repos:


Images are tagged to the version of the proxy they contain. It's strongly suggested to use the latest version of the proxy, and to update the version often.

To use from Kubernetes:

Deploying Cloud SQL Proxy as a sidecar container

Follow this page. See also Connecting from Google Kubernetes Engine.

Third Party

WARNING: These distributions are not officially supported by Google.

Installing via Homebrew

You can find a formula for with Homebrew here.

K8s Cluster Service using Helm

Follow these instructions. This chart creates a Deployment and a Service, but we recommend deploying the proxy as a sidecar container in your pods.

.Net Proxy Wrapper (Nuget Package)

Install via Nuget, follow these instructions.

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