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Feat: Add the posibility to automatically set hostname on run
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‎README.md

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Original file line numberDiff line numberDiff line change
@@ -19,6 +19,7 @@ Feel free to pick your favourite distro.
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- [General options](#general-options)
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- [Inbound debugging](#inbound-debugging)
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- [`ALLOWED_SENDER_DOMAINS` and `ALLOW_EMPTY_SENDER_DOMAINS`](#allowed_sender_domains-and-allow_empty_sender_domains)
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- [`AUTOSET_HOSTNAME` and `AUTOSET_HOSTNAME_SERVICES`](#autoset_hostname-and-autoset_hostname_services)
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- [Log format](#log-format)
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- [Postfix-specific options](#postfix-specific-options)
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- [`RELAYHOST`, `RELAYHOST_USERNAME` and `RELAYHOST_PASSWORD`](#relayhost-relayhost_username-and-relayhost_password)
@@ -167,6 +168,7 @@ Available for all your favourite architectures. Run in your server cluster. Run
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* `INBOUND_DEBUGGING` = Set to `1` to enable detailed debugging in the logs
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* `ALLOWED_SENDER_DOMAINS` = domains which are allowed to send email via this server
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* `ALLOW_EMPTY_SENDER_DOMAINS` = if value is set (i.e: `true`), `ALLOWED_SENDER_DOMAINS` can be unset
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* `AUTOSET_HOSTNAME` and `AUTOSET_HOSTNAME_SERVICES` - use to automatically resolve hostname
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* `LOG_FORMAT` = Set your log format (JSON or plain)
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#### Inbound debugging
@@ -190,6 +192,26 @@ If you want to set the restrictions on the recipient and not on the sender (anyo
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for instance), set `ALLOW_EMPTY_SENDER_DOMAINS` to a non-empty value (e.g. `true`) and `ALLOWED_SENDER_DOMAINS` to an empty
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string. Then extend this image through custom scripts to configure Postfix further.
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#### `AUTOSET_HOSTNAME` and `AUTOSET_HOSTNAME_SERVICES`
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This image can automatically set postfix variable `myhostname` based on reverse DNS resolution of your public IP. To use this
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feature, set `AUTOSET_HOSTNAME` to `1`. The image will then:
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- use an external service to get the public IP address of the image
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- do a reverse DNS lookup to get the hostname associated with that IP
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The image will, by default, try to get the public IP from any of these services, which will be queried in the order defined below:
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1. https://ipinfo.io/ip
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2. https://ifconfig.me/ip
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3. https://icanhazip.com
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4. https://ipecho.net/plain
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5. https://ifconfig.co
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6. https://myexternalip.com/raw
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The first service to return a non-empty, non-error response will be deemed successful. If you have a preference of another order
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and/or wish to use a different service, you can do that by setting the bash array `AUTOSET_HOSTNAME_SERVICES`.
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#### Log format
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The image will by default output logs in human-readable (`plain`) format. If you are deploying the image to Kubernetes, it might

‎build-scripts/postfix-install.sh

+34-2
Original file line numberDiff line numberDiff line change
@@ -22,7 +22,21 @@ do_alpine() {
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apk add --upgrade cyrus-sasl cyrus-sasl-static cyrus-sasl-digestmd5 cyrus-sasl-crammd5 cyrus-sasl-login cyrus-sasl-ntlm libsasl
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apk add postfix postfix-pcre postfix-ldap ${architecture_specific_packages}
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apk add opendkim
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apk add --upgrade ca-certificates tzdata supervisor rsyslog musl musl-utils bash opendkim-utils libcurl jsoncpp lmdb logrotate netcat-openbsd
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apk add --upgrade \
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bash \
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bind-tools \
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ca-certificates \
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jsoncpp \
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libcurl \
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lmdb \
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logrotate \
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musl \
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musl-utils \
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netcat-openbsd \
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opendkim-utils \
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rsyslog \
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supervisor \
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tzdata
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}
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@@ -51,7 +65,25 @@ do_ubuntu() {
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if [ "$(apt-cache search --names-only '^libcurl4t64$')" != "" ]; then
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libcurl="libcurl4t64"
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fi
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apt-get install -y ca-certificates tzdata supervisor rsyslog bash opendkim-tools curl ${libcurl} libjsoncpp25 sasl2-bin postfix-lmdb procps logrotate cron net-tools colorized-logs netcat-openbsd ${RELEASE_SPECIFIC_PACKAGES}
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apt-get install -y \
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${libcurl} ${RELEASE_SPECIFIC_PACKAGES} \
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bash \
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ca-certificates \
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colorized-logs \
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cron \
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curl \
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dnsutils \
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libjsoncpp25 \
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logrotate \
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net-tools \
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netcat-openbsd \
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opendkim-tools \
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postfix-lmdb \
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procps \
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rsyslog \
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sasl2-bin \
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supervisor \
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tzdata \
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apt-get clean
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rm -rf /var/lib/apt/lists/* /tmp/* /var/tmp/*
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}

‎scripts/common-run.sh

+15-2
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@@ -228,8 +228,8 @@ postfix_upgrade_daemon_directory() {
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local dir_alpine="/usr/libexec/postfix" # Alpine
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# Some people will keep the configuration of postfix on an external drive, although this is not strictly neccessary by this
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# image. And when they switch between different distrubtions (Alpine -> Debian and vice versa), the image will fail with the
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# Some people will keep the configuration of postfix on an external drive, although this is not strictly necessary by this
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# image. And when they switch between different distributions (Alpine -> Debian and vice versa), the image will fail with the
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# old configuration. This is a quick and dirty check to solve this issue so we don't get issues like these:
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# https://github.com/bokysan/docker-postfix/issues/147
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local daemon_directory="$(get_postconf "daemon_directory")"
@@ -307,9 +307,22 @@ postfix_reject_invalid_helos() {
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}
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postfix_set_hostname() {
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local ip
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local hostname
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do_postconf -# myhostname
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if [[ -z "$POSTFIX_myhostname" ]] && [[ "${AUTOSET_HOSTNAME}" == "1" ]]; then
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warn "Both ${emphasis}POSTFIX_myhostname${reset} and ${emphasis}AUTOSET_HOSTNAME${reset} are set. ${emphasis}POSTFIX_myhostname${reset} will take precedence and ${emphasis}AUTOSET_HOSTNAME${reset} will be ignored."
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fi
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if [[ -z "$POSTFIX_myhostname" ]]; then
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POSTFIX_myhostname="${HOSTNAME}"
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elif [[ "${AUTOSET_HOSTNAME}" == "1" ]]; then
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ip=$(get_public_ip)
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hostname=$(dig +short -x $IP)
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# Remove the trailing dot
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hostname="${hostname%.}"
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notice "Automatically setting Postfix hostname to ${emphasis}${hostname}${reset} based on your public IP address ${emphasis}${ip}${reset}..."
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POSTFIX_myhostname="${hostname}"
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fi
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}
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‎scripts/common.sh

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@@ -242,7 +242,7 @@ trim() {
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}
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###################################################################
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# Potential fix for #180. Plugin names do not neccessarily match
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# Potential fix for #180. Plugin names do not necessarily match
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# filter names.
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#
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# This is an utility method which converts SASL plugin names into
@@ -284,4 +284,33 @@ convert_plugin_names_to_filter_names() {
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done
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}
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###################################################################
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# Get the public IP of the server. Try different services to ensure
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# that at least one works
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###################################################################
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get_public_ip() {
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local services=(https://ipinfo.io/ip https://ifconfig.me/ip https://icanhazip.com https://ipecho.net/ip https://ifconfig.co https://myexternalip.com/raw)
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local ip
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if [[ -n "${AUTOSET_HOSTNAME_SERVICES}" ]]; then
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services=("${AUTOSET_HOSTNAME_SERVICES}")
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notice "Using user defined ${emphasis}AUTOSET_HOSTNAME_SERVICES${reset}=${emphasis}${AUTOSET_HOSTNAME_SERVICES}${reset} for IP detection"
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else
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debug "Public IP detection will use ${emphasis}${services}${reset} to detect the IP."
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fi
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for service in "${services[@]}"; do
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if ip="$(curl --fail-early --retry-max-time 30 --retry 10 --connect-timeout 5 --max-time 10 -s)"; then
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# Some services, such as ifconfig.co will return a line feed at the end of the response.
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ip="$(printf "%s" "${ip}" | trim)"
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if [[ -n "${ip}" ]]; then
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info "Detected public IP address as ${emphasis}${services}${ip}${reset}."
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break
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fi
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fi
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done
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error "Unable to detect public IP. Please check your internet connection and firewall settings."
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return 1
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}
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export reset green yellow orange orange_emphasis lightblue red gray emphasis underline

‎scripts/run.sh

+1-1
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@@ -32,7 +32,7 @@ postfix_setup_xoauth2_post_setup # (Post) Setup XOAUTH2 authentication
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postfix_setup_networks # Set MYNETWORKS
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postfix_setup_debugging # Enable debugging, if defined
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postfix_setup_sender_domains # Configure allowed sender domains
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postfix_setup_masquarading # Setup masquaraded domains
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postfix_setup_masquarading # Setup masqueraded domains
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postfix_setup_header_checks # Enable SMTP header checks, if defined
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postfix_setup_dkim # Configure DKIM, if enabled
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postfix_setup_smtpd_sasl_auth # Enable sender SASL auth, if defined

‎unit-tests/028_check_get_public_ip.bats

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@@ -0,0 +1,21 @@
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#!/usr/bin/env bats
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load /code/scripts/common.sh
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assert_equals() {
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local expected="$1"
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local actual="$2"
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if [[ "${expected}" != "${actual}" ]]; then
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echo "Expected: \"${expected}\". Got: \"${actual}\"." >&2
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exit 1
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fi
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}
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@test "check if get_public_ip works" {
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local ip1
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local ip2
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ip1=get_public_ip
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AUTOSET_HOSTNAME_SERVICES=(https://ifconfig.co) ip2=get_public_ip
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assert_equals "${ip1}" "${ip2}"
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}
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