Debugging your first flow

Command line options to `flowc`

When running flowc using cargo run -p flowc you should add -- to mark the end of the options passed to cargo, and the start of the options passed to flowc

You can see what they are using --help producing output similar to this:

cargo run -p flowc -- --help                         
    Finished dev [unoptimized + debuginfo] target(s) in 0.12s
     Running 'target/debug/flowc --help'
flowc 0.8.8

USAGE:
    flowc [FLAGS] [OPTIONS] [--] [ARGS]

FLAGS:
    -d, --dump        Dump the flow to .dump files after loading it
    -z, --graphs      Create .dot files for graph generation
    -h, --help        Prints help information
    -p, --provided    Provided function implementations should NOT be compiled from source
    -s, --skip        Skip execution of flow
    -g, --symbols     Generate debug symbols (like process names and full routes)
    -V, --version     Prints version information

OPTIONS:
    -L, --libdir <LIB_DIR|BASE_URL>...    Add a directory or base Url to the Library Search path
    -o, --output <OUTPUT_DIR>             Specify a non-default directory for generated output. Default is $HOME/.flow/lib/{lib_name} for a library.
    -i, --stdin <STDIN_FILENAME>          Read STDIN from the named file
    -v, --verbosity <VERBOSITY_LEVEL>     Set verbosity level for output (trace, debug, info, warn, error (default))

ARGS:
    <FLOW>            the name of the 'flow' definition file or library to compile
    <flow_args>...    Arguments that will get passed onto the flow if it is executed

Command line options to `flowrcli`

By default flowc uses flowrcli to run the flow once it has compiled it. Also it defaults to passing the -n/--native flag to flowrcli so that flows are executed using the native implementations of library functions.

In order to pass command line options on to flowrcli you separate them from the options to flowc after another -- separator.

flowrcli accepts the same -v/--verbosity verbosity options as flowc.

Getting debug output

If you want to follow what the run-time is doing in more detail, you can increase the verbosity level (default level is ERROR) using the -v/--verbosity option.

So, if you want to walk through each and every step of the flow's execution, similar to the previous step by step section then you can do so by using -v debug and piping the output to more (as there is a lot of output!):

cargo run -p flowc -- flowr/examples/fibonacci -- -v debug| more

which should produce output similar to this:

INFO    - 'flowr' version 0.8.8
INFO    - 'flowrlib' version 0.8.8
DEBUG   - Loading library 'context' from 'native'
INFO    - Library 'context' loaded.
DEBUG   - Loading library 'flowstdlib' from 'native'
INFO    - Library 'flowstdlib' loaded.
INFO    - Starting 4 executor threads
DEBUG   - Loading flow manifest from 'file:///Users/andrew/workspace/flow/flowr/examples/fibonacci/manifest.json'
DEBUG   - Loading libraries used by the flow
DEBUG   - Resolving implementations
DEBUG   - Setup 'FLOW_ARGS' with values = '["my-first-flow"]'
INFO    - Maximum jobs dispatched in parallel limited to 8
DEBUG   - Resetting stats and initializing all functions
DEBUG   - Init: Initializing Function #0 '' in Flow #0
DEBUG   -               Input initialized with 'Number(0)'
DEBUG   -               Input initialized with 'Number(1)'
DEBUG   - Init: Initializing Function #1 '' in Flow #0
DEBUG   - Init: Creating any initial block entries that are needed
DEBUG   - Init: Readying initial functions: inputs full and not blocked on output
DEBUG   -               Function #0 not blocked on output, so added to 'Ready' list
DEBUG   - ===========================    Starting flow execution =============================
DEBUG   - Job #0:-------Creating for Function #0 '' ---------------------------
DEBUG   - Job #0:       Inputs: [[Number(0)], [Number(1)]]
DEBUG   - Job #0:       Sent for execution
DEBUG   - Job #0:       Outputs '{"i1":0,"i2":1,"sum":1}'
DEBUG   -               Function #0 sending '1' via output route '/sum' to Self:1
DEBUG   -               Function #0 sending '1' via output route '/sum' to Function #1:0
DEBUG   -               Function #1 not blocked on output, so added to 'Ready' list
DEBUG   -               Function #0 sending '1' via output route '/i2' to Self:0
DEBUG   -               Function #0, inputs full, but blocked on output. Added to blocked list
DEBUG   - Job #1:-------Creating for Function #1 '' ---------------------------
DEBUG   - Job #1:       Inputs: [[Number(1)]]
DEBUG   -                               Function #0 removed from 'blocked' list
DEBUG   -                               Function #0 has inputs ready, so added to 'ready' list
DEBUG   - Job #1:       Sent for execution
DEBUG   - Job #2:-------Creating for Function #0 '' ---------------------------
DEBUG   - Job #2:       Inputs: [[Number(1)], [Number(1)]]
1
DEBUG   - Job #2:       Sent for execution
DEBUG   - Job #2:       Outputs '{"i1":1,"i2":1,"sum":2}'
DEBUG   -               Function #0 sending '2' via output route '/sum' to Self:1
DEBUG   -               Function #0 sending '2' via output route '/sum' to Function #1:0
DEBUG   -               Function #1 not blocked on output, so added to 'Ready' list
DEBUG   -               Function #0 sending '1' via output route '/i2' to Self:0
DEBUG   -               Function #0, inputs full, but blocked on output. Added to blocked list

The 'flow' book