push_docs_to_gh_pages.sh

#!/bin/bash

# Many aspects of this came from https://gist.github.com/domenic/ec8b0fc8ab45f39403dd
# Significant alterations
# - Support for multiple copies of documentation,
#   - only clearing out develop
#   - index.md logging doc history

# How to run:
#  - From repository root .travis/push_docs_to_gh_pages.sh

# Required files / directories (relative from repo root)
# - File: "docs/index.md" with that contains develop docs

# Required ENV Variables
PAGES_TARGET_BRANCH="gh-pages"
LATEST_DOCS_BRANCH="develop"
#  TRAVIS_* variables are set by travis directly and only need to be if testing externally

# Since we are running job matrix, only thie first job slave will need to do the work
if [[ "${TRAVIS_JOB_NUMBER}" =~ \.1$ ]]; then
  # We don't want a pull request automatically updating the repository
  if [ "$TRAVIS_PULL_REQUEST" == "false" ] && { [ "${CURRENT_BRANCH}" == "${LATEST_DOCS_BRANCH}" ] || [ -n "${TRAVIS_TAG}" ]; }; then

    # ENV Variable checks are to help with configuration troubleshooting, they silently exit with unique message.
    # Anyone one of them not set can be used to turn off this functionality.

    # If a version of the project is not defined
    [[ -n "${UTPLSQL_VERSION}" ]] || { echo "variable UTPLSQL_VERSION is not defines or missing value";  exit 0; }
    # Fail if the markdown documentation is not present.
    [[ -f ./docs/index.md ]] || { echo "file docs/index.md not found";  exit 1; }

    # Save some useful information
    SHA=`git rev-parse --verify HEAD`

    # clone the repository and switch to PAGES_TARGET_BRANCH branch
    mkdir pages
    cd pages
    git clone https://${github_api_token}@github.com/${UTPLSQL_REPO} .

    PAGES_BRANCH_EXISTS=$(git ls-remote --heads origin ${PAGES_TARGET_BRANCH})

    if [ -n "$PAGES_BRANCH_EXISTS" ] ; then
      echo "Pages Branch Found"
      git checkout ${PAGES_TARGET_BRANCH}
    else
      echo "Creating Pages Branch"
      git checkout --orphan ${PAGES_TARGET_BRANCH}
      git rm -rf .
    fi
    #clear out develop documentation directory and copy docs contents to it.
    echo "updating 'develop' directory"
    mkdir -p develop
    rm -rf develop/**./* || exit 0
    cp -a ../docs/. ./develop
    # If a Tagged Build then copy to it's own directory as well.
    if [ -n "$TRAVIS_TAG" ]; then
     echo "Creating ${UTPLSQL_VERSION}"
     mkdir -p ${UTPLSQL_VERSION}
     rm -rf ${UTPLSQL_VERSION}/**./* || exit 0
     cp -a ../docs/. ${UTPLSQL_VERSION}
    fi
    # Stage changes for commit
    git add .
    #Check if there are doc changes, if none exit the script
    if [[ -z `git diff HEAD --exit-code` ]] && [ -n "${PAGES_BRANCH_EXISTS}" ] ; then
      echo "No changes to docs detected."
      exit 0
    fi
    #Changes where detected, so we need to update the version log.
    now=$(date +"%d %b %Y - %r")
    export latest=" - [Latest development version](develop/) - Created $now"
    if [ ! -f index.md ]; then
      echo "---" >>index.md
      echo "layout: default" >>index.md
      echo "---" >>index.md
      echo "<!-- Auto generated from .travis/push_docs_to_gh_pages.sh -->" >>index.md
      echo "# Documentation versions" >>index.md
      echo "" >>index.md
      echo "" >>index.md #- 7th line - placeholder for latest release doc
      echo "" >>index.md #- 8th line - placeholder for develop branch doc
      echo "" >>index.md
      echo "## Released Version Doc History" >>index.md
      echo "" >>index.md
    fi
    #If build running on a TAG - it's a new release - need to add it to documentation
    if [ -n "${TRAVIS_TAG}" ]; then
      latest_release=" - [${TRAVIS_TAG} documentation](${UTPLSQL_VERSION}/) - Created $now"
      sed -i '7s@.*@'"Latest release ${latest_release}"'@'  index.md
    fi
    #replace 4th line in log
    sed -i '8s@.*@'"${latest}"'@'  index.md
    #Add and Commit the changes back to pages repo.
    git add .
    git commit -m "Deploy to gh-pages branch: base commit ${SHA}"
    # Now that we're all set up, we can push.
    git push --quiet origin HEAD:${PAGES_TARGET_BRANCH}
  fi
fi