Programmatically create deploy keys, on server and GitHub, for an existing git repository

ssh-github-deploy.sh

#!/bin/sh

KEYDIR=~/.ssh/keys.d/github-deploy
CONFDIR=~/.ssh/config.d/github-deploy

github_username=noah
github_access_token=$(cat ~/.secret/github_access_token)

rp=$(git rev-parse --is-inside-work-tree 2>/dev/null)

if [ $? -eq 0 ] && [ "$rp" = "true" ]; then
        url="$(git config --get remote.origin.url)"
        reponame="$(echo $url | cut -d/ -f2)"
        keyfile=$KEYDIR/$reponame
        config=$CONFDIR/$reponame

        repo_id="github-deploy-$reponame.github.com"

        git remote set-url origin git@$repo_id:$github_username/$reponame

        echo "+ config: $config"
        cat << EOF > $config
Host $repo_id
        HostName github.com
        User git
        IdentitiesOnly yes
        IdentityFile $keyfile
EOF

        echo "+ local key: $keyfile"
        echo -e 'y\n' | ssh-keygen -t rsa \
                -f $keyfile \
                -C https://github.com/$github_username/$reponame\
                -N ''\
                -q 1>/dev/null

        # delete all existing deploy keys
        curl \
                -H"Authorization: token $github_access_token"\
                https://api.github.com/repos/noah/$reponame/keys 2>/dev/null\
                | jq '.[] | .id ' | \
                while read _id; do
                        echo "- deploy key: $_id"
                        curl \
                                -X "DELETE"\
                                -H"Authorization: token $github_access_token"\
                                https://api.github.com/repos/noah/$reponame/keys/$_id 2>/dev/null
                done 

        # add the keyfile to github
        echo
        echo "+ deploy key:"
        echo -n ">> "
        {
                curl \
                        -i\
                        -H"Authorization: token $github_access_token"\
                        --data @- https://api.github.com/repos/noah/$reponame/keys << EOF
        {
                "title" : "$repo_id $(date)",
                "key" : "$(cat $keyfile.pub)",
                "read_only" : false
        }
EOF
        } 2>/dev/null | head -1 # status code should be 201

        echo
        echo "local key:"
        ssh-keygen -lf $keyfile

        echo
        echo "config:"
        cat $config

else
        echo 'Not a git repository'
        exit
fi