#!/bin/bash

##################################################
# ENV                                            #
# - PROMETHEUS_OPTS                              #
# - ALERTMANAGER_OPTS                            #
# - GRAFANA_OPTS                                 #
# - LOKI_OPTS                                    #
# Mount dir                                      #
# - /etc/prometheus                              #
# - /var/log/prometheus                          #
# - /var/lib/prometheus                          #
##################################################

set -euo pipefail
export LANG=en_US.UTF-8
trap Quit EXIT

PIDS=
GOT_SIGTERM=
LOG_DIR='/var/log/prometheus'
DATA_DIR='/var/lib/prometheus'
CONF_DIR='/etc/prometheus'

function Print {
    local file=/dev/null
    [ '-f' = "$1" ] && file=$2 && shift && shift
    date +"[%F %T] $*" | tee -a $file
}

function Quit {
    local running
    while running= ; do
        pkill -f sleep          && running=1 && Print killing sleep ...
        pkill -f grafana-server && running=1 && Print killing grafana-server ...
        pkill -f prometheus     && running=1 && Print killing prometheus ...
        pkill -f alertmanager   && running=1 && Print killing alertmanager ...
        pkill -f loki           && running=1 && Print killing loki ...
        [ -z "$running" ] && break
        sleep 1
    done
    Print Container stopped.
    test -n "$GOT_SIGTERM"
}

function SideCar {
    local md5= last_md5=$(find $CONF_DIR -maxdepth 1 -type f \
        -regex ".*\.yml\|.*\.tmpl" | xargs -I ^ md5sum ^ | md5sum)
    while sleep 10; do
        md5=$(find $CONF_DIR -maxdepth 1 -type f \
            -regex ".*\.yml\|.*\.tmpl" | xargs -I ^ md5sum ^ | md5sum)
        [ "$md5" != "$last_md5" ] \
            && last_md5=$md5 \
            && Print Reloading conf ... \
            && pkill -HUP -f prometheus \
            && pkill -HUP -f alertmanager
    done
}

function Init {
    mkdir -p $DATA_DIR/{tsdb,alertmanager,grafana,loki}
    [ -f $CONF_DIR/prometheus.yml ] || echo 'global:
  scrape_interval: 15s
  evaluation_interval: 15s
  scrape_timeout: 10s

alerting:
  alertmanagers:
  - static_configs:
    - targets:
      - 127.0.0.1:9093

rule_files:
# - node_rules.yml

scrape_configs:
#- job_name: prometheus
#  honor_labels: true
#  static_configs:
#  - targets:
#    - 127.0.0.1:9100
#    labels:
#      host: 127.0.0.1

#- job_name: nodes
#  static_configs:
#  - targets:
#    - ip_1:9100
#    - ip_2:9100
#  metric_relabel_configs:
#  - source_labels: [instance]
#    target_label: host
#    regex: "([^:]+):.+"
' > $CONF_DIR/prometheus.yml
    [ -f $CONF_DIR/alertmanager.yml ] || echo 'global:
  resolve_timeout: 10m

templates:
# - xxxx.tmpl

route:
  group_by: [alertname]
  group_wait: 10s
  group_interval: 10s
  repeat_interval: 1m
  receiver: alert

receivers:
- name: alert

inhibit_rules:
  - source_match:
      severity: emergency
    target_match_re:
      severity: "warning|critical"
    equal: [host]
' > $CONF_DIR/alertmanager.yml
    [ -f $CONF_DIR/grafana.ini ] \
        || cp -af /usr/share/grafana/conf/sample.ini $CONF_DIR/grafana.ini
    [ -d $CONF_DIR/provisioning ] \
        || cp -af /usr/share/grafana/conf/provisioning $CONF_DIR/provisioning
    [ -f $CONF_DIR/loki.yml ] || echo "
auth_enabled: false

server:
  http_listen_port: 3100
  grpc_listen_port: 9096
  log_level: warn

ingester:
  wal:
    enabled: true
    dir: $DATA_DIR/loki/db/wal
  lifecycler:
    address: 127.0.0.1
    ring:
      kvstore:
        store: inmemory
      replication_factor: 1
    final_sleep: 0s
  chunk_idle_period: 1h
  max_chunk_age: 1h
  chunk_target_size: 1048576
  chunk_retain_period: 30s
  max_transfer_retries: 0

schema_config:
  configs:
    - from: 2020-10-24
      store: boltdb-shipper
      object_store: filesystem
      schema: v11
      index:
        prefix: index_
        period: 24h

storage_config:
  boltdb_shipper:
    active_index_directory: $DATA_DIR/loki/db/boltdb-shipper-active
    cache_location: $DATA_DIR/loki/db/boltdb-shipper-cache
    cache_ttl: 24h
    shared_store: filesystem
  filesystem:
    directory: $DATA_DIR/loki/db/chunks

compactor:
  working_directory: $DATA_DIR/loki/db/boltdb-shipper-compactor
  shared_store: filesystem

limits_config:
  reject_old_samples: true
  reject_old_samples_max_age: 168h

chunk_store_config:
  max_look_back_period: 0s

table_manager:
  retention_deletes_enabled: false
  retention_period: 0s

ruler:
  storage:
    trapype: local
    local:
      directory: $DATA_DIR/loki/db/rules
  rule_path: $DATA_DIR/loki/db/rules-temp
  alertmanager_url: http://127.0.0.1:9093
  ring:
    kvstore:
      store: inmemory
  enable_api: true
" > $CONF_DIR/loki.yml
}

function StartProc {
    Print Starting alertmanager ...
    alertmanager \
        --config.file=$CONF_DIR/alertmanager.yml \
        --storage.path=$DATA_DIR/alertmanager \
        --web.external-url=http://0.0.0.0:9093/alertmanager/ \
        ${ALERTMANAGER_OPTS:-} &>> $LOG_DIR/alertmanager.out &
    PIDS="$PIDS $!"
    sleep 2

    Print Starting prometheus ...
    prometheus \
        --config.file=$CONF_DIR/prometheus.yml \
        --web.external-url=prometheus \
        --web.console.templates=/usr/share/prometheus/consoles \
        --web.console.libraries=/usr/share/prometheus/console_libraries \
        --storage.tsdb.path=$DATA_DIR/tsdb \
        ${PROMETHEUS_OPTS:-} &>> $LOG_DIR/prometheus.out &
    PIDS="$PIDS $!"
    sleep 2

    Print Starting grafana-server ...
    grafana-server \
        -homepath /usr/share/grafana \
        -config $CONF_DIR/grafana.ini \
        ${GRAFANA_OPTS:-} web &>> $LOG_DIR/grafana.out &
    PIDS="$PIDS $!"
    sleep 2

    Print Starting loki ...
    loki \
        --config.file=$CONF_DIR/loki.yml \
        ${LOKI_OPTS:-} &>> $LOG_DIR/loki.out &
    PIDS="$PIDS $!"
    sleep 2

    Print Starting sidecar ...
    SideCar &
    PIDS="$PIDS $!"

    Print All components started.
}

function Main {
    local pid=
    Init
    StartProc
    trap "GOT_SIGTERM=1; Print Got SIGTERM ..." SIGTERM
    while [ -z "$GOT_SIGTERM" ] && sleep 1; do
        for pid in $PIDS; do
            [ ! -e /proc/$pid ] && Print Unexpected error! && exit
        done
    done
}

# Start here
Main