Add logging and retry_constant

* Conditional logging functions based on BASH_LIB_LOG_LEVEL with
  appropriate colouring for each level.
* retry_constant function, similar to retry but with a retry_constant
  interval between attempts.

Author: hughsaunders

helpers/lib

@@ -19,11 +19,16 @@ function spopd(){
     popd >/dev/null || die "popd failed :("
 }
 
+# Test if a variable contains a number
+function is_num(){
+    [[ ${1:-invalid} =~ ^-?[0-9\.]*$ ]]
+}
+
 # Retry a command multiple times until it succeeds, with escalating
 # delay between attempts.
 # Delay is 2 * n + random up to 30s, then 30s + random after that.
 # For large numbers of retries the max delay is effectively the retry
-# in minutes.
+# count in minutes.
 # Based on:
 # https://gist.github.com/sj26/88e1c6584397bb7c13bd11108a579746
 # but now quite heavily modified.
@@ -40,7 +45,7 @@ function retry {
     local retries=$1
     shift
 
-    if ! [[ ${retries} =~ ^[0-9\.]*$ ]]; then
+    if ! is_num "${retries}"; then
         echo "Invalid number of retries: ${retries} for command '${*}'".
         exit 1
     fi
@@ -72,3 +77,42 @@ function retry {
     done
     return 0
 }
+
+# retry function that waits a constant number of seconds between attempts.
+function retry_constant {
+    if [[ ${#} -lt 3 ]]; then
+        echo "retry usage: retry <retries> <interval (seconds)> <command>"
+        exit 1
+    fi
+
+    local retries=$1; shift
+    local interval=$1; shift
+
+    if ! is_num "${retries}"; then
+        echo "Invalid number of retries: ${retries} for command '${*}'".
+        exit 1
+    fi
+
+    if ! is_num "${interval}"; then
+        echo "Invalid interval in seconds: ${retries} for command '${*}'".
+        exit 1
+    fi
+
+    local count=0
+    until eval "$@"; do
+        # Command failed, otherwise until would have skipped the loop
+
+        # Store return code so it can be reported to the user
+        exit=$?
+        count=$((count + 1))
+        if [ "${count}" -lt "${retries}" ]; then
+            echo "'${*}' Retry $count/$retries exited $exit, retrying in $interval seconds..."
+            sleep "${interval}"
+        else
+            # Out of retries :(
+            echo "Retry $count/$retries exited $exit, no more retries left."
+            return $exit
+        fi
+    done
+    return 0
+}

init

@@ -1,9 +1,15 @@
-#!/bin/bash
+#!/usr/bin/env bash
 
 ## Initialisation Functions for the
 ## Conjurinc Bash Library
 
-# Shell Options
+if (( ${BASH_VERSINFO[0]} < 4 )); then
+    echo "Bash Lib requires bash v4 or greater"
+    echo "Current Bash Version: ${BASH_VERSION}"
+    exit 1
+fi
+
+# Shell Otions
 set -euo pipefail
 
 # This script should be sourced before any of

logging/lib

@@ -1,7 +1,12 @@
-#!/bin/bash
+#!/usr/bin/env bash
 
+echo $BASH_VERSION
 : "${BASH_LIB_DIR:?BASH_LIB_DIR must be set. Please source bash-lib/init before other scripts from bash-lib.}"
 
+export BASH_LIB_LOG_LEVEL=info
+declare -A BASH_LIB_LOG_LEVELS=([debug]=1 [info]=2 [warn]=3 [error]=4 [fatal]=5 )
+declare -A BASH_LIB_LOG_COLOURS=( [debug]="0;37;40" [info]="0;36;40" [warn]="0;33;40" [error]="1;31;40" [fatal]="1;37;41" )
+
 # Add logging functions here
 
 function announce() {
@@ -10,4 +15,49 @@ function announce() {
   echo "$@"
   echo " "
   echo "++++++++++++++++++++++++++++++++++++++"
-}
+}
+
+function check_log_level(){
+  level="${1}"
+  if [[ ${level} =~ debug|info|warn|error|fatal ]];
+  then
+    return 0
+  else
+    echo "${level} is not a valid BASH_LIB_LOG_LEVEL, it should be debug|info|warn|error|fatal"
+    return 1
+  fi
+}
+
+function log {
+  runtime_log_level="${BASH_LIB_LOG_LEVEL}"
+  write_log_level="${1}"
+  msg="${2}"
+
+  check_log_level "${runtime_log_level}"
+  check_log_level "${write_log_level}"
+
+  if (( ${BASH_LIB_LOG_LEVELS[${write_log_level}]} >= ${BASH_LIB_LOG_LEVELS[${runtime_log_level}]} )); then
+    echo -e "\e[${BASH_LIB_LOG_COLOURS[${write_log_level}]}m${msg}\e[0m"
+  fi
+}
+
+function debug(){
+  log debug "${*}"
+}
+
+function info(){
+  log info "${*}"
+}
+
+function warn(){
+  log warn "${*}"
+}
+
+function error(){
+  log error "${*}"
+}
+
+function fatal(){
+  log fatal "${*}"
+}
+

run-tests

@@ -1,4 +1,4 @@
-#!/bin/bash
+#!/usr/bin/env bash
 
 # This script is an entry point, so init
 # is not assumed to have been run

tests-for-this-repo/helpers.bats

@@ -46,6 +46,42 @@ teardown(){
     assert_failure
 }
 
+@test "is_num fails with no arguments" {
+    run is_num
+    assert_output ""
+    assert_failure
+}
+
+@test "is_num fails with alphabetical input" {
+    run is_num foo
+    assert_output ""
+    assert_failure
+}
+
+@test "is_num suceeds with integer" {
+    run is_num foo
+    assert_output 123
+    assert_success
+}
+
+@test "is_num suceeds with negative integer" {
+    run is_num foo
+    assert_output -123
+    assert_success
+}
+
+@test "is_num suceeds with float" {
+    run is_num foo
+    assert_output 123.4
+    assert_success
+}
+
+@test "is_num suceeds with negative float" {
+    run is_num foo
+    assert_output -123.4
+    assert_success
+}
+
 @test "retry runs command only once if it succeeds the first time" {
     retryme(){
         date >> ${afile}
@@ -116,3 +152,87 @@ teardown(){
     assert_success
     assert_equal $(wc -l <${afile}) 1
 }
+
+
+
+
+# ***************
+
+
+@test "retry_constant runs command only once if it succeeds the first time" {
+    retry_me(){
+        date >> ${afile}
+    }
+    run retry_constant 3 1 retry_me
+    assert_success
+    assert_equal $(wc -l <${afile}) 1
+}
+
+@test "retry_constant doesn't introduce delay when the command succeeds first time" {
+    retry_me(){
+        date >> ${afile}
+    }
+    start=$(date +%s)
+    run retry_constant 3 10 retry_me
+    end=$(date +%s)
+    assert [ "$(( start + 1 ))" -ge "${end}" ]
+    assert_success
+}
+
+@test "retry_constant runs n times on consecutive failure and waits between attempts" {
+    retry_me(){
+        date >> ${afile}
+        false
+    }
+    start=$(date +%s)
+    run retry_constant 2 1 retry_me
+    end=$(date +%s)
+    # introduces at least a two second delay between attempts
+    assert [ "$(( start + 2 ))" -le "${end}" ]
+    assert_failure
+    assert_equal $(wc -l <${afile}) 2
+}
+
+@test "retry_constant returns after first success" {
+    retry_me(){
+        date >> "${afile}"
+        case $(wc -l < ${afile}) in
+            *1)
+                return 1
+            ;;
+            *)
+                return 0
+            ;;
+        esac
+    }
+    run retry_constant 3 1 retry_me
+    assert_success
+    assert_equal $(wc -l <${afile}) 2
+}
+
+@test "retry_constant fails with less than three arguments" {
+    run retry_constant 3 1
+    assert_failure
+    assert_output --partial usage
+    assert [ ! -e "${temp_dir}/appendfile" ]
+}
+
+@test "retry_constant fails with non-integer retry count" {
+    run retry_constant "this" 1 date
+    assert_failure
+    assert_output --partial number
+    assert [ ! -e "${temp_dir}/appendfile" ]
+}
+
+@test "retry_constant fails with non-integer interval" {
+    run retry_constant 2 "this" date
+    assert_failure
+    assert_output --partial interval
+    assert [ ! -e "${temp_dir}/appendfile" ]
+}
+
+@test "retry_constant succeeds with compound statements" {
+    run retry_constant 3 1 "true && date >> ${afile}"
+    assert_success
+    assert_equal $(wc -l <${afile}) 1
+}

tests-for-this-repo/logging.bats

@@ -7,3 +7,25 @@
     assert_output --partial "one two one two"
     assert_success
 }
+
+@test "check_log_level succeeds with valid level" {
+    run check_log_level
+    assert_success
+}
+
+@test "check_log_level fails with invalid level" {
+    run BASH_LIB_LOG_LEVEL="foo" check_log_level
+    assert_failure
+}
+
+@test "debug doesn't output anything using the default info level" {
+    run debug foo
+    assert_success
+    assert_output ""
+}
+
+@test "debug outputs its inputs while using the debug level" {
+    run BASH_LIB_LOG_LEVEL="debug" debug foo
+    assert_success
+    assert_output "foo"
+}

tests-for-this-repo/run-bats-tests

@@ -1,4 +1,4 @@
-#!/bin/bash
+#!/usr/bin/env bash
 
 set -euo pipefail
 

tests-for-this-repo/run-python-lint

@@ -1,4 +1,4 @@
-#!/bin/bash
+#!/usr/bin/env bash
 
 # This script is an entry point, so init
 # is not assumed to have been run