Using AWS S3 to Store DevStream State

Tiexin Guo
DevStream
Published in
3 min readMay 30, 2022

In our latest release v0.6.0, using AWS S3 to store DevStream state is supported.

In this blog, we are going to demonstrate the usage of AWS S3 to store DevStream’s state files.

Terminology

State: if you don’t already know about DevStream state, please read this doc and this blog helps, too.

Backend: where to actually store the state file. It can be either local or s3 at the moment.

Configuration

In the main config file, we have a section to configure the state. Currently, local and S3 are supported.

Local example:

varFile: variables-gitops.yamltoolFile: tools-gitops.yamlstate:
backend: local
options:
stateFile: devstream.state

S3 example:

varFile: variables-gitops.yamltoolFile: tools-gitops.yamlstate:
backend: s3
options:
bucket: devstream-remote-state
region: ap-southeast-1
key: devstream.state

More on configuring state here.

In short, we can use the “backend” keyword to specify where to store the state: either locally or in an S3 bucket. If S3 is used, we need to specify the bucket, region, and the S3 key as well.

Config File Examples

In this demo, we use the following configs:

config.yaml:

varFile: variables-gitops.yamltoolFile: tools-gitops.yamlstate:
backend: s3
options:
bucket: devstream-test-remote-state
region: ap-southeast-1
key: devstream.state

variables-gitops.yaml:

githubUsername: IronCore864
repoName: dtm-test-go
defaultBranch: main
dockerhubUsername: ironcore864argocdNameSpace: argocd
argocdDeployTimeout: 5m

tools-gitops.yaml:

tools:
- name: github-repo-scaffolding-golang
instanceID: default
options:
owner: [[ githubUsername ]]
org: ""
repo: [[ repoName ]]
branch: [[ defaultBranch ]]
image_repo: [[ dockerhubUsername ]]/[[ repoName ]]

Getting Started

Before reading on, now is a good time to check if you have configured your AWS related environment variables correctly or not.

For macOS/Linux users, do:

export AWS_ACCESS_KEY_ID=ID_HERE
export AWS_SECRET_ACCESS_KEY=SECRET_HERE
export AWS_DEFAULT_REGION=REGION_HERE

For more information, see the official document here.

Apply

Then let’s run dtm apply:

tiexin@mbp ~/work/devstream-io/devstream $ ./dtm apply
2022-05-30 17:07:59 ℹ [INFO] Apply started.
2022-05-30 17:07:59 ℹ [INFO] Using dir <.devstream> to store plugins.
2022-05-30 17:07:59 ℹ [INFO] Using s3 backend. Bucket: devstream-test-remote-state, region: ap-southeast-1, key: devstream.state.
2022-05-30 17:08:00 ℹ [INFO] Tool (github-repo-scaffolding-golang/default) found in config but doesn't exist in the state, will be created.
Continue? [y/n]
Enter a value (Default is n): y
2022-05-30 17:08:08 ℹ [INFO] Start executing the plan.
2022-05-30 17:08:08 ℹ [INFO] Changes count: 1.
2022-05-30 17:08:08 ℹ [INFO] -------------------- [ Processing progress: 1/1. ] --------------------
2022-05-30 17:08:08 ℹ [INFO] Processing: (github-repo-scaffolding-golang/default) -> Create ...
2022-05-30 17:08:12 ℹ [INFO] The repo dtm-test-go has been created.
2022-05-30 17:08:29 ✔ [SUCCESS] Tool (github-repo-scaffolding-golang/default) Create done.
2022-05-30 17:08:29 ℹ [INFO] -------------------- [ Processing done. ] --------------------
2022-05-30 17:08:29 ✔ [SUCCESS] All plugins applied successfully.
2022-05-30 17:08:29 ✔ [SUCCESS] Apply finished.

As we can see from the output, the S3 backend is used, and it also shows the bucket and key you are using, and in which region this bucket lives.

Checking the State File

After apply, let's download the state file from S3 and check it out:

tiexin@mbp ~/work/devstream-io/devstream $ aws s3 cp s3://devstream-test-remote-state/devstream.state .

And if we open the downloaded file, we will see something similar to the following:

github-repo-scaffolding-golang_default:
name: github-repo-scaffolding-golang
instanceid: default
dependson: []
options:
branch: main
image_repo: ironcore864/dtm-test-go
org: ""
owner: IronCore864
repo: dtm-test-go
resource:
org: ""
outputs:
org: ""
owner: IronCore864
repo: dtm-test-go
repoURL: https://github.com/IronCore864/dtm-test-go.git
owner: IronCore864
repoName: dtm-test-go

which is exactly the same as if we were using the local backend to store state.

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