Update readme.

Author: alex-ac

README.md

@@ -1,2 +1,95 @@
-# github-action-ssh-docker-compose
+## github-action-ssh-docker-compose
 Simple github action to run docker-compose on remote host.
+
+This action packs contents of the action workspace into archive.
+Logs into remote host via ssh. Unpacks the workspace there and runs
+`docker-compose up -d` command.
+
+Comparing to other actions with similar behavior this one does not use any
+unknown docker-images. It is entirely built from Dockerfile on top of
+`alpine:3.8`.
+
+## Inputs
+
+ * `ssh_private_key` - Private SSH key used for logging into remote system.
+   Please, keep your key securely in github secrets.
+ * `ssh_host` - Remote host name.
+ * `ssh_port` - Remote port for SSH connection. Default is 22.
+ * `ssh_user` - Remote user which should have access to docker.
+ * `docker_compose_prefix` - Project name passed to compose. Each docker
+   container will have this prefix in name.
+ * `docker_compose_file` - Path to the docker-compose file in the repository.
+
+# Usage example
+
+Let's say we have a repo with single docker-compose file in it and remote
+ubuntu based server with docker and docker-compose installed.
+
+1. Generate key pair, do not use a password here.
+
+```
+ssh-keygen -t ed25519 deploy_key
+```
+
+2. Create a user which will deploy containers for you on the remote server, do
+not set password for this user:
+
+```
+ssh example.com
+$ sudo useradd -m -b /var/lib -G docker docker-deploy
+```
+
+3. Allow to log into that user with the key you generated on the step one.
+
+```
+scp deploy_key.pub example.com:~
+ssh example.com
+$ sudo mkdir /var/lib/docker-deploy/.ssh
+$ sudo chown docker-deploy:docker-deploy /var/lib/docker-deploy/.ssh
+$ sudo install -o docker-deploy -g docker-deploy -m 0600 deploy_key.pub /var/lib/docker-deploy/.ssh/authorized_keys
+$ sudo chmod 0500 /var/lib/deploy/.ssh
+$ rm deploy_key.pub
+```
+
+4. Test that key works.
+
+```
+ssh -i deploy_key [email protected]
+```
+
+5. Add private key and user name into secrets for the repository. Let's say that
+names of the secrets are `EXAMPLE_COM_SSH_PRIVATE_KEY` and
+`EXAMPLE_COM_SSH_USER`.
+
+6. Remove your local copy of the ssh key:
+
+```
+rm deploy_key
+```
+
+7. Setup a github-actions workflow (e.g. `.github/workflows/main.yml`):
+
+```
+name: Deploy
+
+on:
+  push:
+    branches: [ master ]
+
+jobs:
+  deploy:
+    runs-on: ubuntu-latest
+
+    steps:
+    - uses: actions/checkout@v2
+
+    - uses: alex-ac/github-action-ssh-docker-compose@master
+      name: Docker-Compose Remote Deployment
+      with:
+        ssh_host: example.com
+        ssh_private_key: ${{ secrets.EXAMPLE_COM_SSH_PRIVATE_KEY }}
+        ssh_user: ${{ secrets.EXAMPLE_COM_SSH_USER }}
+        docker_compose_prefix: example_com
+```
+
+8. You're all set!