hyperhive/nix/script-tests/agent-bao-fetch.sh

# Cases for ./agent-bao-fetch.nix. Each case gets a fresh runtime directory and
# credentials directory, runs one unit's script under the unit's `UMask=0377`
# with a clean environment, and asserts on the exit code, the output, the
# files left behind and the `bao` calls made.
set -uo pipefail

failures=0
count=0

fail() {
  echo "FAILED: $case: $*" >&2
  failures=$((failures + 1))
}

# The umask cases are only meaningful if a 0400 file cannot be reopened for
# writing, which is not so for root.
probe=$TMPDIR/umask-probe
: >"$probe"
chmod 0400 "$probe"
if (: >"$probe") 2>/dev/null; then
  echo "a 0400 file is writable by this builder, so the UMask=0377 cases would prove nothing" >&2
  exit 1
fi

# setup FORGE <description>
setup() {
  prefix=$1
  case="$prefix: $2"
  local unit_var=${prefix}_UNIT script_var=${prefix}_SCRIPT path_var=${prefix}_PATH addr_var=${prefix}_BAO_ADDR
  unit=${!unit_var}
  unit_path=${!path_var}
  bao_addr=${!addr_var}
  dir=$(mktemp -d)
  rt=$dir/rt
  creds=$dir/creds
  log=$dir/bao.log
  mkdir -m 0700 "$rt"
  mkdir "$creds"
  printf cert >"$creds/hive-agent-bao-cert"
  printf key >"$creds/hive-agent-bao-key"
  : >"$log"
  if ! sed "s|/run/$unit/|$rt/|g" "${!script_var}" >"$dir/script"; then
    echo "cannot read the rendered script for $unit" >&2
    exit 1
  fi
  chmod +x "$dir/script"
  if grep -q '/run/' "$dir/script"; then fail "the script still names /run after the rewrite"; fi
  if ! grep -qF "$rt/bao.err" "$dir/script"; then fail "the rewrite did not reach the script's error file"; fi

  login_rc=0
  login_out=s.fake-token
  login_err=
  kv_rc=0
  kv_out=the-secret
  kv_err=
}

go() {
  count=$((count + 1))
  (
    umask 0377
    cd "$dir" || exit 99
    exec env -i \
      PATH="$FAKE_BAO_BIN:$unit_path" \
      BAO_ADDR="$bao_addr" \
      CREDENTIALS_DIRECTORY="$creds" \
      FAKE_BAO_LOG="$log" \
      FAKE_BAO_LOGIN_RC="$login_rc" \
      FAKE_BAO_LOGIN_OUT="$login_out" \
      FAKE_BAO_LOGIN_ERR="$login_err" \
      FAKE_BAO_KV_RC="$kv_rc" \
      FAKE_BAO_KV_OUT="$kv_out" \
      FAKE_BAO_KV_ERR="$kv_err" \
      "$dir/script"
  ) >"$dir/out" 2>"$dir/err"
  rc=$?
}

expect_rc() {
  if [ "$rc" != "$1" ]; then fail "exit $rc, expected $1; stderr: $(<"$dir/err")"; fi
}

expect_err() {
  if ! grep -qF -- "$1" "$dir/err"; then fail "stderr lacks '$1'; stderr: $(<"$dir/err")"; fi
}

expect_no_err() {
  if grep -qF -- "$1" "$dir/err"; then fail "stderr has '$1'; stderr: $(<"$dir/err")"; fi
}

expect_out() {
  if ! grep -qF -- "$1" "$dir/out"; then fail "stdout lacks '$1'; stdout: $(<"$dir/out")"; fi
}

# expect_calls <line>... — the exact `bao` argument lines, in order.
expect_calls() {
  local want
  want=$(printf '%s\n' "$@")
  if [ "$(<"$log")" != "${want%$'\n'}" ]; then fail "bao calls were '$(<"$log")', expected '$*'"; fi
}

expect_file() {
  if [ ! -e "$1" ]; then
    fail "$1 missing"
    return
  fi
  if [ "$(<"$1")" != "$2" ]; then fail "$1 holds '$(<"$1")', expected '$2'"; fi
}

expect_no_file() {
  if [ -e "$1" ]; then fail "$1 left behind"; fi
}

secret_name=token
path=secret/swarm/agents/a1/forge-token
missing_msg="no forge token at $path yet"
login_call="login -method=cert -token-only"
kv_call="kv get -field=value $path"

setup FORGE "no store identity delivered"
: >"$creds/hive-agent-bao-cert"
go
expect_rc 0
expect_err "has no store identity"
expect_calls

setup FORGE "a credential that cannot be read"
chmod 0000 "$creds/hive-agent-bao-key"
go
expect_rc 1
expect_err "cannot read $creds/hive-agent-bao-key"
expect_calls

setup FORGE "bao's stderr file cannot be created"
chmod 0500 "$rt"
go
chmod 0700 "$rt"
expect_rc 1
expect_err "could not create $rt/bao.err, so bao never ran"
expect_calls

setup FORGE "the store refuses the login with an HTTP 4xx"
login_rc=2
login_err=$'Error authenticating: Error making API request.\n\nURL: PUT '"$bao_addr"$'/v1/auth/cert/login\nCode: 403. Errors:\n\n* permission denied\n'
go
expect_rc 1
expect_err "refused this agent's certificate login with HTTP 403:"
expect_err "* permission denied"
expect_calls "$login_call"

setup FORGE "the store fails the login with another HTTP status"
login_rc=2
login_err=$'Error authenticating: Error making API request.\n\nCode: 500. Errors:\n\n* internal error\n'
go
expect_rc 1
expect_err "failed this agent's certificate login with HTTP 500:"
expect_err "* internal error"
expect_calls "$login_call"

setup FORGE "the store refuses the certificate with a TLS alert"
login_rc=2
login_err="Error authenticating: Put \"$bao_addr/v1/auth/cert/login\": remote error: tls: unknown certificate authority"
go
expect_rc 1
expect_err "refused this agent's certificate in the TLS handshake:"
expect_err "remote error: tls: unknown certificate authority"
expect_calls "$login_call"

setup FORGE "the store does not answer"
login_rc=2
login_err="Error authenticating: Put \"$bao_addr/v1/auth/cert/login\": dial tcp: lookup bao.t.local: no such host"
go
expect_rc 1
expect_err "got no answer from the swarm secret store at $bao_addr"
expect_err "no such host"
expect_calls "$login_call"

# The unit keeps its runtime directory between runs.
setup FORGE "nothing minted at the agent's path yet"
printf old >"$rt/$secret_name"
chmod 0400 "$rt/$secret_name"
kv_rc=2
kv_err="No value found at secret/data/swarm/agents/a1"
go
expect_rc 0
expect_err "$missing_msg"
expect_err "No value found"
expect_calls "$login_call" "$kv_call"
expect_file "$rt/$secret_name" old

setup FORGE "a first fetch writes the secret 0400"
go
expect_rc 0
expect_out "fetched this agent's"
expect_no_err "Permission denied"
expect_calls "$login_call" "$kv_call"
expect_file "$rt/$secret_name" the-secret
if [ "$(stat -c %a "$rt/$secret_name")" != 400 ]; then fail "$secret_name is mode $(stat -c %a "$rt/$secret_name"), expected 400"; fi
expect_no_file "$rt/bao.err"
expect_no_file "$rt/token.new"

# `UMask=0377` makes every file the script creates 0400, the login's own
# `bao.err` included, and a redirect into a 0400 file fails before bao starts.
setup FORGE "0400 files already in place do not block the fetch"
printf stale >"$rt/bao.err"
chmod 0400 "$rt/bao.err"
printf stale >"$rt/token.new"
chmod 0400 "$rt/token.new"
go
expect_rc 0
expect_out "fetched this agent's"
expect_no_err "Permission denied"
expect_no_err "refused"
expect_calls "$login_call" "$kv_call"
expect_file "$rt/$secret_name" the-secret

setup FORGE "an unchanged token is left in place"
printf the-secret >"$rt/token"
chmod 0400 "$rt/token"
before=$(stat -c %i "$rt/token")
go
expect_rc 0
expect_out "is unchanged"
expect_file "$rt/token" the-secret
if [ "$(stat -c %i "$rt/token")" != "$before" ]; then fail "the unchanged token was replaced"; fi
expect_no_file "$rt/token.new"

setup FORGE "a rotated token replaces the old one"
printf old >"$rt/token"
chmod 0400 "$rt/token"
go
expect_rc 0
expect_out "fetched this agent's forge token"
expect_file "$rt/token" the-secret
expect_no_file "$rt/token.new"

if [ "$failures" -ne 0 ]; then
  echo "script-test-agent-bao-fetch: $failures failed assertions over $count runs" >&2
  exit 1
fi
echo "script-test-agent-bao-fetch: $count runs, all assertions hold"