Logging updates prior to supporting configuration through the API

[dianpopa]

Changes

• changed signature of the set functions inside the logger to receive reference to self (when configuring the logger from an external struct we need to be able to call the set functions separately).
• added a constant to tell us when user attempts initialization of the logging system
• updated unit tests to match changes

Testing

Build Time

Prerequisite

## add the necessary musl target to the active toolchain
rustup target add x86_64-unknown-linux-musl

Build tests

cargo fmt —all
cargo build # no warning
cargo build —release # no warning
sudo env "PATH=$PATH" cargo test --all #no warin
sudo env "PATH=$PATH" cargo kcov —all # overall 44.3%

Integration Testing

rm -f /tmp/firecracker.socket && \
target/debug/firecracker --api-sock=/tmp/firecracker.socket

• in another console start sending curl requests for starting basic firecracker guest

curl --unix-socket /tmp/firecracker.socket -i  \
     -X PUT "http://localhost/boot-source" \
     -H "accept: application/json" \
     -H "Content-Type: application/json" \
     -d "{ 
           \"boot_source_id\": \"alinux_kernel\",
           \"source_type\": \"LocalImage\", 
           \"local_image\": 
                { 
                    \"kernel_image_path\": \"${kernel_path}\" 
                }
        }"

echo 2
curl --unix-socket /tmp/firecracker.socket -i \
     -X PUT "http://localhost/machine-config" \
     -H "accept: application/json" \
     -H "Content-Type: application/json" \
     -d "{ \"vcpu_count\": 4, \"mem_size_mib\": 256}"

# Add root block device
echo 3
curl --unix-socket /tmp/firecracker.socket -i \
     -X PUT "http://localhost/drives/root" \
     -H "accept: application/json" \
     -H "Content-Type: application/json" \
     -d "{ 
            \"drive_id\": \"root\",
            \"path_on_host\": \"${rootfs_path}\", 
            \"is_root_device\": true, 
            \"permissions\": \"rw\", 
            \"state\": \"Attached\"
         }"


# Add readonly device
echo 4
curl --unix-socket /tmp/firecracker.socket -i \
     -X PUT "http://localhost/drives/read_only_drive" \
     -H "accept: application/json" \
     -H "Content-Type: application/json" \
     -d "{ 
            \"drive_id\": \"read_only_drive\",
            \"path_on_host\": \"${ro_drive_path}\", 
            \"is_root_device\": false, 
            \"permissions\": \"ro\", 
            \"state\": \"Attached\"
         }"

# Create a tap interface
ip tuntap add name vmtap33 mode tap
ifconfig vmtap33 192.168.241.1/24 up
echo 5
curl --unix-socket /tmp/firecracker.socket -i \
     -X PUT "http://localhost/network-interfaces/1" \
     -H "accept: application/json" \
     -H "Content-Type: application/json" \
     -d "{ 
            \"iface_id\": \"1\", 
            \"host_dev_name\": \"vmtap33\", 
            \"guest_mac\": \"06:00:00:00:00:01\", 
            \"state\": \"Attached\" 
        }"

echo 6
curl --unix-socket /tmp/firecracker.socket -i \
     -X PUT "http://localhost/actions/start" \
     -H  "accept: application/json" \
     -H  "Content-Type: application/json" \
     -d "{  
            \"action_id\": \"start\",  
            \"action_type\": \"InstanceStart\"
         }"

# Get the response of starting the instance
echo 7
curl --unix-socket /tmp/firecracker.socket -i \
     -X GET "http://localhost/actions/start" \
     -H "accept: application/json"

sudo ip link delete vmtap33

• in the initial console the guest should start up

# login: ...
# reboot

[acatangiu]

typo in commit message: s/confiuring/configuring

[acatangiu]

nit: This error message is a bit nondescript, maybe change it to something like "Reinitialization of logger is not allowed" or "Logger already initialized" ?

[acatangiu]

• no need for .ok() before .unwrap()
• while comparing references is fine in Rust because auto DeRef() is being done ( https://www.reddit.com/r/rust/comments/2dmzf6/why_do_equality_tests_of_references_seem_to/ ), it looks a bit weird; I suggest removing the '&' from '&INITIALIZED' if the compiler doesn't complain about it.
• nit: instead of error on "state == INITIALIZED", it's better practice to error on "state != UNINITIALIZED", that way if for whatever reason a new state is added, this check is still valid and correct.

[dianpopa]

• I did try it without references. If I call unwrap on INIT_RES it would try to move the content and given that INIT_RES is static the compiler complains about it. It does complain if I remove the &.

[acatangiu]

why is this change needed?

[dianpopa]

I need to be able to do the configuration of the logger (i.e. call the set functions) progressively. In the first version where the functions would return self I would only be able to do it from one call (Logger::new.set_bla.set_bla2 ...). But in the case of the API I need to be able to parse the config that I receive and call the set functions separately.

[acatangiu]

ok

[dianpopa]

@acatangiu The typo is in the pr description. I updated it. The commit message looks ok to me.