Coverage profile generation for Go on Circle CI utilizing classic app engine

gocover.sh

#!/usr/bin/env bash
#
# Generate test coverage statistics for Go packages.
#
# Works around the fact that `go test -coverprofile` currently does not work
# with multiple packages, see https://code.google.com/p/go/issues/detail?id=6909
#
# largely based on the below links with a few small changes
# to support classic google appengine
#
# http://mlafeldt.github.io/blog/test-coverage-in-go/
# https://github.com/mlafeldt/chef-runner/blob/v0.7.0/script/coverage
#
# Usage: script/coverage [--html|--coveralls] [test args..]
#
#     --html      Additionally create HTML report and open it in browser
#     --coveralls Push coverage statistics to coveralls.io
#

set -e

workdir=.cover
profile="$workdir/cover.out"
mode=count

# current branch of the repository, used if the environment variable is not set
git_branch=$(git symbolic-ref --short HEAD)

generate_cover_data() {
    rm -rf "$workdir"
    mkdir "$workdir"

    pkgs=''
    if hash goapp 2>/dev/null; then
        pkgs=$(goapp list $(glide nv))
    else
        pkgs=$(go list $(glide nv))
    fi
    for pkg in $pkgs; do
        # skip if there are no *_test.go files
        stat "$GOPATH/src/$pkg/"*_test.go > /dev/null 2>&1 || { echo "SKIP $pkg [no test files]"; continue; }

        echo "TEST $pkg"
        f="$workdir/$(echo "$pkg" | tr / -).cover"

        if hash goapp 2>/dev/null; then
            # use goapp if it is present
            time goapp test -v -covermode="$mode" -coverprofile="$f" "$@" "$pkg"
        else
            time go test -v -covermode="$mode" -coverprofile="$f" "$@" "$pkg"
        fi
    done

    echo "mode: $mode" >"$profile"
    grep -h -v "^mode:" "$workdir"/*.cover >>"$profile"
}

show_cover_report() {
    go tool cover -"${1}"="$profile"
}

push_to_coveralls() {
    echo "Pushing coverage statistics to coveralls.io"
    # specify git branch based on the environment in case

    # allow for either COVERALLS_TOKEN and COVERALLS_REPO_TOKEN to be used
    coveralls_token=${COVERALLS_TOKEN:-$COVERALLS_REPO_TOKEN}

    GIT_BRANCH=${CIRCLE_BRANCH:-$git_branch} goveralls \
        -coverprofile="$profile" \
        -service=circleci \
        -repotoken "$coveralls_token"
}

# increase file handle limit for appengine
ulimit -n 2048

flag=$1
shift

generate_cover_data "$@"
show_cover_report func

case "$flag" in
"")
    ;;
--html)
    show_cover_report html ;;
--coveralls)
    push_to_coveralls || echo "push to coveralls failed" ;;
*)
    echo >&2 "error: invalid option: $1"; exit 1 ;;
esac