Less noisy build logging

[andreasjansson]

Build logs now just print a high level trace of what's going on, e.g.

$ cog build
INFO[0000] --> Uploading /Users/andreas/r8/cog-examples/hello-world 
INFO[0000] --> Building package...                      
INFO[0000] --> Received model                           
INFO[0000] --> Building cpu image                       
INFO[0002]   * Installing Python prerequisites          
INFO[0002]   * Installing Python 3.8                    
INFO[0002]   * Installing Cog                           
INFO[0002]   * Copying code                             
INFO[0003] Successfully built 288e75031f73              
INFO[0003] --> Testing model                            
INFO[0003] Deploying container no_registry/hello-world:288e75031f73 for target docker-cpu 
INFO[0005] Waiting for model container to become accessible 
INFO[0005] Got successful ping response from container  
INFO[0005] Inference result length: 9, mime type: text/html 
INFO[0005] Inference result length: 9, mime type: text/html 
INFO[0016] --> Inserting into database                  
Successfully built 2894e44e45ad05e2ec43849ecadd29e448ded229

and if something goes wrong it spits out the logs for that specific build step:

$ cog build
INFO[0000] --> Uploading /Users/andreas/r8/cog-examples/hello-world 
INFO[0000] --> Building package...                      
INFO[0000] --> Received model                           
INFO[0000] --> Building cpu image                       
INFO[0002]   * Installing Python 3.8                    
INFO[0002]   * Installing Python prerequisites          
INFO[0002]   * Installing Python packages               
INFO[0005] #9 sha256:1a209009316a45300d4ee523e1d596a3ca4c6fb69a8aa2a0f5713c8a182b9cb8 
INFO[0005] #9 DONE 1.3s                                 
INFO[0005]                                              
INFO[0005] #10 [ 7/13] RUN pip install   asdfasdfadsffdsafdsaf==1.1.1.1.1 
INFO[0005] #10 sha256:3970572ce4364565003b3220e1e874c31d430d9f2ffc8c1c94823203fa8db7e5 
INFO[0005] #10 1.352 ERROR: Could not find a version that satisfies the requirement asdfasdfadsffdsafdsaf==1.1.1.1.1 (from versions: none) 
INFO[0005] #10 1.352 ERROR: No matching distribution found for asdfasdfadsffdsafdsaf==1.1.1.1.1 
INFO[0005] #10 1.530 WARNING: You are using pip version 20.2.3; however, version 21.0.1 is available. 
INFO[0005] #10 1.530 You should consider upgrading via the '/root/.pyenv/versions/3.8.8/bin/python3.8 -m pip install --upgrade pip' command. 
INFO[0005] #10 ERROR: executor failed running [/bin/sh -c pip install   asdfasdfadsffdsafdsaf==1.1.1.1.1]: exit code: 1 
INFO[0005] ------                                       
INFO[0005]  > [ 7/13] RUN pip install   asdfasdfadsffdsafdsaf==1.1.1.1.1: 
INFO[0005] ------                                       
INFO[0005] executor failed running [/bin/sh -c pip install   asdfasdfadsffdsafdsaf==1.1.1.1.1]: exit code: 1 
Error: Error: Failed to build Docker image: exit status 1
Usage:
  cog build [flags]

Flags:
  -h, --help          help for build
  -r, --repo string   Remote repository, e.g. andreas/jazz-composer (for replicate.ai), or replicate.my-company.net/andreas/jazz-composer

Global Flags:
  -v, --verbose   Verbose output

FATA[0005] Error: Failed to build Docker image: exit status 1