While we support initializing records via coercion from an expression
list, e.g.,
local x: X = [$x1=1, $x2=2];
this can sometimes obscure the code to readers, e.g., when assigning to
value declared and typed elsewhere. The language runtime has a similar
overhead since instead of just constructing a known type it needs to
check at runtime that the coercion from the expression list is valid;
this can be slower than just writing the readible code in the first
place, see #4559.
With this patch we use explicit construction, e.g.,
local x = X($x1=1, $x2=2);
It helps during testing to be able to control whether the Supervisor process
also routs node output to the console, in addition to writing to output
files. Since the Supervisor runs as the main process in Docker containers, its
output becomes visible in "docker logs" that way, simplifying diagnostics.
This improves the framework's handling of Zeek node stdout and stderr by
extending the (script-layer) Supervisor functionality.
- The Supervisor _either_ directs Zeek nodes' stdout/stderr to files _or_ lets
you hook into it at the script level. We'd like both: files make sense to allow
inspection outside of the framework, and the framework would benefit from
tapping into the streams e.g. for error context. We now provide the file
redirection functionality in the Supervisor, in addition to the hook
mechanism. The hook mechanism also builds up rolling windows of up to
100 lines (configurable) into stdout/stderr.
- The new Mangement::Supervisor::API::notify_node_exit event notifies
subscribers (agents, really) that a particular node has exited (and is possibly
being restarted by the Supervisor). The event includes the name of the node,
plus its recent stdout/stderr context.
