"mirage describe" should reflect configured state of the unikernel

[mato]

With the changes in #703 and followup in mirage/functoria#85 the Mirage describe subcommand should show the configured state of the unikernel rather than the "default" state, i.e. reflect any keys persisted from a previous run of mirage configure.

Also, this subcommand currently accepts all the standard mirage options, including -t. Does that serve any useful use-case? If not then the command should behave identically to build following mirage/functoria#85, i.e. error out if configure has not been run first, not accept any configuration keys and only display the configured state.

@hannesm @yomimono @samoht Please comment on what the best behaviour with regard to the new workflow is here.

[yomimono]

I don't frequently use describe, but when I do I'm trying to figure out the dependency graph of modules, so I'm using it with the --dot output and want the configured state of the unikernel (the behavior that maps to previous --eval).

We don't describe mirage describe in introductory materials (if I remember correctly), but I imagine that it would be useful in key discovery for unconfigured unikernels (or confusing if it didn't do that, maybe) were we to teach its use.

[mato]

Relevant discussion from the list is here: https://lists.xenproject.org/archives/html/mirageos-devel/2016-12/msg00011.html

I think the conclusion on the list was that in the configured case describe should always behave as with --eval and reflect the configured values (but possibly have a --no-eval) while in the unconfigured case it should do what it does today.

For key discovery from an end user point of view that should be something like mirage configure --help?

[mato]

/cc @Drup

[hannesm]

this is still broken...

[hannesm]

some logging output in functoria leads to:

mirage: [WARNING] read mirage configure -t virtio -r home
mirage: [WARNING] cached context is prng=stdlib (default), target=virtio
mirage: [WARNING] context is prng=stdlib (default), target=unix (default)
mirage: [WARNING] merging with some default
mirage: [WARNING] merged context is prng=stdlib (default), target=virtio
Name       canopy
Root       /usr/home/hannes/devel/mirage/Canopy
Keys       interface=0 (default), ipv4=198.167.222.208/24 (default),
  ipv4-gateway=198.167.222.1 (default), logs= (default), port=8080 (default),
  prng=stdlib (default), push_hook=push (default),
  remote=https://github.com/Engil/__blog.git (default),
  target=unix (default), tls_port= (default), warn_error=false (default)

I suspect it has to be in this code

          let partial = match full_eval with
            | Some true  -> false
            | Some false -> true
            | None -> not (Cache.present cached_context)
          in
          Config'.eval ~with_required:false ~partial context config

where the merged context is passed in, but nevertheless as target unix is shown.

For some unknown reason, the read -r home is not at all put into the cached context (which it should), and thus defaults to remote=https://github.com/Engil/__blog.git (default),

Another abnormality is that prng=stdlib(default) is somehow put into the cached context, although no --prng key is on disk.

maybe @Drup has an idea...

[samoht]

I think this should now be fixed with the HEAD version of functoria, which should be compatible with the HEAD version of mirage when #849 is merged.

[yomimono]

849 is now merged; what are the release dependencies?

[samoht]

@yomimono: I guess functoria needs to be released first and then mirage. Or I didn't understand your question :-)

[yomimono]

That is what I meant! Thanks.

[yomimono]

I don't think this is fixed as of mirage 3.0.5. Configuring the network example with --dhcp true never gives mirage describe output reflecting that key; it always just shows defaults:

4.06.0+afl🐫  (master) 13.01 mirageos:~/mirage-skeleton/device-usage/network$ mirage clean
4.06.0+afl🐫  (master) 13.01 mirageos:~/mirage-skeleton/device-usage/network$ mirage describe
Name       network
Build-dir  /home/user/mirage-skeleton/device-usage/network/./
Keys       dhcp=false (default), interface=tap0 (default),
  interfaces=0.0.0.0 (default), ipv4=10.0.0.2/24 (default),
  ipv4-gateway=10.0.0.1 (default), logs= (default), net=direct (default),
  port=8080 (default), prng=stdlib (default), socket= (default),
  target=unix (default), target_debug=false, warn_error=false (default)
Output     
4.06.0+afl🐫  (master) 13.01 mirageos:~/mirage-skeleton/device-usage/network$ mirage configure -t unix --dhcp true
4.06.0+afl🐫  (master) 13.01 mirageos:~/mirage-skeleton/device-usage/network$ mirage describe
Name       network
Build-dir  /home/user/mirage-skeleton/device-usage/network/./
Keys       dhcp=false (default), interface=tap0 (default), logs= (default),
  net=direct (default), port=8080 (default), prng=stdlib (default),
  target=unix (default), target_debug=false, warn_error=false (default)
Output     
4.06.0+afl🐫  (master) 13.01 mirageos:~/mirage-skeleton/device-usage/network$ make
mirage build
ocamlfind ocamldep -package tcpip.unix -package tcpip.udp -package tcpip.tcp -package tcpip.stack-direct -package tcpip.icmpv4 -package tcpip.ethif -package tcpip.arpv4 -package tcpip -package mirage-unix -package mirage-types-lwt -package mirage-types -package mirage-runtime -package mirage-random -package mirage-net-unix -package mirage-logs -package mirage-clock-unix -package lwt -package functoria-runtime -package charrua-client-mirage -predicates mirage_unix -modules main.ml > main.ml.depends
ocamlfind ocamldep -package tcpip.unix -package tcpip.udp -package tcpip.tcp -package tcpip.stack-direct -package tcpip.icmpv4 -package tcpip.ethif -package tcpip.arpv4 -package tcpip -package mirage-unix -package mirage-types-lwt -package mirage-types -package mirage-runtime -package mirage-random -package mirage-net-unix -package mirage-logs -package mirage-clock-unix -package lwt -package functoria-runtime -package charrua-client-mirage -predicates mirage_unix -modules key_gen.ml > key_gen.ml.depends
ocamlfind ocamldep -package tcpip.unix -package tcpip.udp -package tcpip.tcp -package tcpip.stack-direct -package tcpip.icmpv4 -package tcpip.ethif -package tcpip.arpv4 -package tcpip -package mirage-unix -package mirage-types-lwt -package mirage-types -package mirage-runtime -package mirage-random -package mirage-net-unix -package mirage-logs -package mirage-clock-unix -package lwt -package functoria-runtime -package charrua-client-mirage -predicates mirage_unix -modules unikernel.ml > unikernel.ml.depends
ocamlfind ocamlc -c -g -g -bin-annot -safe-string -principal -strict-sequence -package tcpip.unix -package tcpip.udp -package tcpip.tcp -package tcpip.stack-direct -package tcpip.icmpv4 -package tcpip.ethif -package tcpip.arpv4 -package tcpip -package mirage-unix -package mirage-types-lwt -package mirage-types -package mirage-runtime -package mirage-random -package mirage-net-unix -package mirage-logs -package mirage-clock-unix -package lwt -package functoria-runtime -package charrua-client-mirage -predicates mirage_unix -w A-4-41-42-44 -color always -o key_gen.cmo key_gen.ml
ocamlfind ocamlc -c -g -g -bin-annot -safe-string -principal -strict-sequence -package tcpip.unix -package tcpip.udp -package tcpip.tcp -package tcpip.stack-direct -package tcpip.icmpv4 -package tcpip.ethif -package tcpip.arpv4 -package tcpip -package mirage-unix -package mirage-types-lwt -package mirage-types -package mirage-runtime -package mirage-random -package mirage-net-unix -package mirage-logs -package mirage-clock-unix -package lwt -package functoria-runtime -package charrua-client-mirage -predicates mirage_unix -w A-4-41-42-44 -color always -o unikernel.cmo unikernel.ml
ocamlfind ocamlc -c -g -g -bin-annot -safe-string -principal -strict-sequence -package tcpip.unix -package tcpip.udp -package tcpip.tcp -package tcpip.stack-direct -package tcpip.icmpv4 -package tcpip.ethif -package tcpip.arpv4 -package tcpip -package mirage-unix -package mirage-types-lwt -package mirage-types -package mirage-runtime -package mirage-random -package mirage-net-unix -package mirage-logs -package mirage-clock-unix -package lwt -package functoria-runtime -package charrua-client-mirage -predicates mirage_unix -w A-4-41-42-44 -color always -o main.cmo main.ml
ocamlfind ocamlopt -c -g -g -bin-annot -safe-string -principal -strict-sequence -package tcpip.unix -package tcpip.udp -package tcpip.tcp -package tcpip.stack-direct -package tcpip.icmpv4 -package tcpip.ethif -package tcpip.arpv4 -package tcpip -package mirage-unix -package mirage-types-lwt -package mirage-types -package mirage-runtime -package mirage-random -package mirage-net-unix -package mirage-logs -package mirage-clock-unix -package lwt -package functoria-runtime -package charrua-client-mirage -predicates mirage_unix -w A-4-41-42-44 -color always -o key_gen.cmx key_gen.ml
ocamlfind ocamlopt -c -g -g -bin-annot -safe-string -principal -strict-sequence -package tcpip.unix -package tcpip.udp -package tcpip.tcp -package tcpip.stack-direct -package tcpip.icmpv4 -package tcpip.ethif -package tcpip.arpv4 -package tcpip -package mirage-unix -package mirage-types-lwt -package mirage-types -package mirage-runtime -package mirage-random -package mirage-net-unix -package mirage-logs -package mirage-clock-unix -package lwt -package functoria-runtime -package charrua-client-mirage -predicates mirage_unix -w A-4-41-42-44 -color always -o unikernel.cmx unikernel.ml
ocamlfind ocamlopt -c -g -g -bin-annot -safe-string -principal -strict-sequence -package tcpip.unix -package tcpip.udp -package tcpip.tcp -package tcpip.stack-direct -package tcpip.icmpv4 -package tcpip.ethif -package tcpip.arpv4 -package tcpip -package mirage-unix -package mirage-types-lwt -package mirage-types -package mirage-runtime -package mirage-random -package mirage-net-unix -package mirage-logs -package mirage-clock-unix -package lwt -package functoria-runtime -package charrua-client-mirage -predicates mirage_unix -w A-4-41-42-44 -color always -o main.cmx main.ml
ocamlfind ocamlopt -g -linkpkg -g -package tcpip.unix -package tcpip.udp -package tcpip.tcp -package tcpip.stack-direct -package tcpip.icmpv4 -package tcpip.ethif -package tcpip.arpv4 -package tcpip -package mirage-unix -package mirage-types-lwt -package mirage-types -package mirage-runtime -package mirage-random -package mirage-net-unix -package mirage-logs -package mirage-clock-unix -package lwt -package functoria-runtime -package charrua-client-mirage -predicates mirage_unix key_gen.cmx unikernel.cmx main.cmx -o main.native
4.06.0+afl🐫  (master) 13.01 mirageos:~/mirage-skeleton/device-usage/network$ mirage describe
Name       network
Build-dir  /home/user/mirage-skeleton/device-usage/network/./
Keys       dhcp=false (default), interface=tap0 (default), logs= (default),
  net=direct (default), port=8080 (default), prng=stdlib (default),
  target=unix (default), target_debug=false, warn_error=false (default)
Output     

[samoht]

Hum Indeed. I think I just checked that "configure -> build" was working as expected and assumed it would work for describe ... and we are not definitely not testing this. I'll have a quick look at my patches ...

[samoht]

@Drup do you remember why you separated the eval of eval_cached in mirage/functoria@9b74280 ? Can't describe just use eval_cached as well?

[Drup]

@samoht Honestly, I don't remember. Maybe I just forgot to do it. Having eval/eval_cache separate was useful for handling failure, iirc.

[samoht]

Do you remember which case of failures? I will try to add some tests, so keen to test the failure modes as well.