docs-suggestions

# https://secure.helpscout.net/conversation/916382713/20759/
# https://secure.helpscout.net/conversation/927209463/21258/

Semaphore server location

All Semaphore jobs are being executed in data-center in Germany.

The same caching layer is used both for macOS and Linux, however, Linux is geographically closer to the caching 
layer and at the moment we do not have concrete plans for spreading macOS caching layers. 


# https://secure.helpscout.net/conversation/917751522/20919/   -- Classic

Job is asking for passphrase

Keys generated with the newer version of RSA are not compatible with Semaphore Classic. 
In case you find a prompt asking for a passphrase, it is likely that the machine 
on which the key was generated is using the newer version of RSA.

The easiest solution is to generate a new key in an SSH debugging session (https://semaphoreci.com/docs/ssh-access-to-build-environment.html). 
You may achieve this by running the following command and copying the output to the configuration file prompt in 
Semaphore web application:

```bash
ssh-keygen -f ~/.ssh/id_rsa_semaphore -t rsa -N "" && cat ~/.ssh/id_rsa_semaphore
```

# https://secure.helpscout.net/conversation/925727668/21222/

How to move Docker images between jobs:

You can push the built Docker image from one job to Docker registry close to our datacenter and then 
pulling it in the next job. The geographically closest Docker registries are located in AWS Frankfurt (eu-central-1), 
Google Docker Registry in Frankfurt, and DockerHub.

However, for public images, DockerHub is the most stable since Semaphore uses our DockerHub mirror. 
Unfortunately, our DockerHub mirror does not support private Docker images at the moment.

# https://secure.helpscout.net/conversation/923639540/21126/

Caching ubuntu packages:

Generally, caching Ubuntu packages is not needed since Semaphore uses the Ubuntu mirror 
which is located in the same datacenter as Semaphore builders.

If the package originates from the custom software repository, you may cache the content of /var/apt/archive/ folder. 
This would eliminate the need for downloading the packages from the Internet but the installation would still be required. 
This approach saves some (download) time but requires cache logic to be added to your project.
The following example shows how to cache vips-libs packages that are hosted in the specific package repository:

```yaml
checkout
mkdir $HOME/vips-libs && cd $HOME/vips-libs && cache restore vips-libs
if [ $(ls -l | wc -l)>0 ]; then sudo mv * /var/cache/apt/archives/ && cd $HOME; fi;
echo "deb http://cz.archive.ubuntu.com/ubuntu cosmic main universe" | sudo tee -a /etc/apt/sources.list
sudo apt-get update ; sudo apt-get install -y libvips-dev libvips-tools libvips42
cd /var/cache/apt/archives && cache store vips-libs-$(ls | checksum) .
cd $HOME/$SEMAPHORE_PROJECT_DIR
```

The idea is to restore the cache (if exists) and set up the custom repository in case the cache archive is not found. 
If the cache archive exists, packages will be restored to the `/var/apt/archive/` folder, 
one used by the `apt-get install` command by default. If the cache archive does not exist, 
packages will be downloaded from the repository. After installation, the packages located in `/var/apt/archive/`
folder will be saved to the cache.

For more information on the cache mechanism, please see https://docs.semaphoreci.com/article/54-toolbox-reference#cache.

# https://secure.helpscout.net/conversation/918246402/20935/

How to create a Github machine user:

For projects using multiple submodules you can the machine user on GitHub and allowing it to access your repositories 

More information about this topic here: (https://developer.github.com/v3/guides/managing-deploy-keys/#machine-users)

1. Create a machine user with access to repositories
2. Generate a new SSH key-pair for the machine user (public part goes to Github)
3. Adding the private part of the key to Semaphore

Please note that the git client uses only the first SSH key from ssh-agent.

# https://secure.helpscout.net/conversation/927689942/21286/

(Check if we want to do this)
Change here https://docs.semaphoreci.com/article/100-heroku-deployment#define-the-deployment-pipeline

`SEMAPHORE_GIT_PR_SHA` instead of `SEMAPHORE_GIT_BRANCH` 

# https://secure.helpscout.net/conversation/935469757/21540/

(Check if we want to do this)

Change these:
https://docs.semaphoreci.com/article/97-continuous-deployment-static-website
https://docs.semaphoreci.com/article/141-netlify-continuous-deployment

To include `checksum` in the cache key names.