Retry Az Create

1#!/usr/bin/env bash
2# retry-az-create.sh
3# Wraps the idempotent `(az ... show ...) || (az ... create ...)` pair with
4# silent retries against transient ARM frontend errors (connection resets,
5# 429/502/503/504, timeouts).
6#
7# Usage:
8#   ./retry-az-create.sh "<show-command>" "<create-command>"
9#
10# Both commands are passed as single shell-quoted strings. The script:
11#   - runs `show` first (short-circuits any partially-succeeded prior attempt
12#     and avoids false NameAlreadyExists / Conflict errors);
13#   - if `show` fails, runs `create`;
14#   - on transient failure, retries up to 2 times (3 attempts total) with
15#     5s then 15s backoff;
16#   - on non-transient failure, surfaces the original error and exits 1.
17#
18# Examples:
19#   ./retry-az-create.sh \
20#       "az group show -n my-rg --only-show-errors" \
21#       "az group create -n my-rg -l eastus2"
22#
23#   ./retry-az-create.sh \
24#       "az appservice plan show -n my-plan -g my-rg --only-show-errors" \
25#       "az appservice plan create -n my-plan -g my-rg --is-linux --sku P0v3 -l eastus2"
26
27set -uo pipefail
28
29SHOW_CMD="${1:?Usage: $0 \"<show-command>\" \"<create-command>\"}"
30CREATE_CMD="${2:?Usage: $0 \"<show-command>\" \"<create-command>\"}"
31
32TRANSIENT='Connection reset|Connection aborted|ConnectionError|Read timed out|BadGatewayConnection|ServiceUnavailable|Max retries exceeded|TooManyRequests|\b429\b|\b50[234]\b'
33
34for attempt in 1 2 3; do
35    # Run show silently; on failure, run create and capture stderr.
36    if err=$({ eval "$SHOW_CMD -o none 2>/dev/null" || eval "$CREATE_CMD -o none"; } 2>&1); then
37        exit 0
38    fi
39
40    if ! echo "$err" | grep -qE "$TRANSIENT"; then
41        echo "$err" >&2
42        exit 1
43    fi
44
45    if [ "$attempt" -eq 3 ]; then
46        echo "$err" >&2
47        echo "ARM frontend is returning transient errors — please retry in a few minutes." >&2
48        exit 1
49    fi
50
51    sleep "$([ "$attempt" -eq 1 ] && echo 5 || echo 15)"
52done