Magic Values

Describes magic values on the swarming server

Introduction

There are a few "magic" values in the isolate and swarming server. Also some dimensions and state values have special meaning.

run_isolated.py/.zip understands the following. These values should be set in the command section of the .isolate file.

${ISOLATED_OUTDIR}: If found on command line argument, replaced by the temporary directory that is uploaded back to the server after the task execution. This causes run_isolated to print a [run_isolated_out_hack] statement after the task.
${SWARMING_BOT_FILE}: If found on command line argument, replaced by a file written to by the swarming bot's on_before_task() hook in the swarming server's custom bot_config.py. This is used by a swarming bot to communicate state of the bot to tasks.

When a Swarming bot is running a task, the following environment variables are always set:

The following environment variables may be set to alter bot behavior:

SWARMING_EXTERNAL_BOT_SETUP=1 disables bot_config.setup_bot hook.
SWARMING_GRPC_PROXY=<url> and ISOLATED_GRPC_PROXY=<url> override the equivalent value in the bot config.
LUCI_GRPC_PROXY_VERBOSE dumps out additional gRPC proxy information if set to a truthy value (e.g. 1).
LUCI_GRPC_PROXY_TLS_ROOTS=<file> and points to a .crt file containing certificate authorities. LUCI_GRPC_PROXY_TLS_OVERRIDE=<name> specifies the name of the server in the certificate. These are useful for testing a gRPC proxy running on localhost but with TLS enabled. Unlike the *_GRPC_PROXY env vars, these are shared between Swarming and Isolated since they're only used in the limited case when you need to override TLS. See /client/utils/grpc_proxy.py for more information.

id: must be a single value in the list, which also must be unique. It's what uniquely identify the bot.
quarantined: if present, it specifies the bot self-quarantined, as it found out it needs manual sysadmin assistance before being able to accept any task. An example is that it doesn't enough free disk space.

cost_usd_hour: reports the base cost of this bot in $USD/hour.
lease_expiration_ts: when set to an integer or floating point value, informs the server of the time (in UTC seconds since epoch) that the bot will disconnect from the server. The server will not allow the bot to reap any tasks projected to end after the bot disconnects.
periodic_reboot_secs: when set to a integer, instructs the server to send a reboot command after this period. The actual period is fuzzed with a 10% delta.
quarantined: has the same meaning as in dimensions. It's also supported as a state.
bot_group_cfg_version: version identifier of the server defined configuration (extract from bots.cfg), applied to the bot during initial handshake. The server will ask the bot to restart if this configuration changes.