Cloud Spanner Emulator - docker initialization

0
votes

I'm trying to setup a docker container that starts cloud spanner and that initializes it.

Using this official docker image provided by google: gcr.io/cloud-spanner-emulator/emulator

I'm looking to automatically initialize spanner on start.

I tried various things with the docker file, to summarize:

FROM gcr.io/cloud-spanner-emulator/emulator

RUN some gcloud command after to initialize local spanner db

But absence of informations on how this image works makes it hard to find if it's even possible to initialize it everytime the container starts.

I repeat myself, I need this to be run automatically when the container mounts. It's going to build pipelines.

Is there a way to do that with this provided docker image? Or should I create my own dockerfile that installs the emulator via gcloud cli?

2
google-cloud-spannergoogle-cloud-spanner-emulator

2 Answers

1
votes

If I understand correctly, you wish to start up the Spanner emulator within a dockerfile.

You can create your own dockerfile to build the emulator.

Please utilize these docker commands:

    docker pull gcr.io/cloud-spanner-emulator/emulator
    docker run -p 9010:9010 -p 9020:9020 gcr.io/cloud-spanner-emulator/emulator

To startup the spanner emulator.

EDIT:

With further clarification, it seems that what is being attempted is currently not an available feature of the official Docker image "gcr.io/cloud-spanner-emulator/emulator".

No documentation identifies how to utilize the official Spanner Emulator Docker image to run initialization scripts, neither the GCP Documentation nor the Spanner emulator README. Such, as running gcloud commands on startup to create a spanner instance, upload a DDL file and add a database using said file.

The workaround identified by OP in the comments, seems to be the best solution as of now.

2
votes

Here is a docker file example that allows to start docker emulator and to initialize with some custom gcloud commands

FROM google/cloud-sdk:slim

RUN apt-get install -y google-cloud-sdk google-cloud-sdk-spanner-emulator

COPY ./start_spanner.bash start_spanner.bash
COPY ./schema.ddl schema.ddl

CMD ./start_spanner.bash

Here is a sample content of file start_spanner.bash.

#!/bin/bash

set -m

gcloud beta emulators spanner start --host-port=0.0.0.0:9010 &

# configure gcloud cli to connect to emulator
gcloud config set auth/disable_credentials true
gcloud config set project someproject
gcloud config set api_endpoint_overrides/spanner http://localhost:9020/

# create spanner instance
gcloud spanner instances create someinstance \
  --config=emulator-config \
  --description="Test Instance" \
  --nodes=1

# create spanner database with the given schema
gcloud spanner databases create somedb \
 --instance=someinstance \
 --ddl-file=schema.ddl

fg %1

And the file schema.ddl is just your spanner ddl to run to create tables in the emulator as per spanner's documentation.