Getting Started

Installation

So far we are offering two different variants for the installation. You can choose between Docker or pre-built binaries which are stored on our download mirrors and GitHub releases. Maybe we will also provide system packages for the major distributions later if we see the need for it.

Docker

TBD

Binaries

TBD

Configuration

We provide overall three different variants of configuration. The variant based on environment variables and commandline flags are split up into global values and command-specific values.

Envrionment variables

If you prefer to configure the service with environment variables you can see the available variables below.

Global

HELLO_CONFIG_FILE
Path to config file, empty default value
HELLO_LOG_LEVEL
Set logging level, defaults to info
HELLO_LOG_COLOR
Enable colored logging, defaults to true
HELLO_LOG_PRETTY
Enable pretty logging, defaults to true

Server

HELLO_TRACING_ENABLED
Enable sending traces, defaults to false
HELLO_TRACING_TYPE
Tracing backend type, defaults to jaeger
HELLO_TRACING_ENDPOINT
Endpoint for the agent, empty default value
HELLO_TRACING_COLLECTOR
Endpoint for the collector, empty default value
HELLO_TRACING_SERVICE
Service name for tracing, defaults to hello
HELLO_DEBUG_ADDR
Address to bind debug server, defaults to 0.0.0.0:9109
HELLO_DEBUG_TOKEN
Token to grant metrics access, empty default value
HELLO_DEBUG_PPROF
Enable pprof debugging, defaults to false
HELLO_DEBUG_ZPAGES
Enable zpages debugging, defaults to false
HELLO_HTTP_ADDR
Address to bind http server, defaults to 0.0.0.0:9105
HELLO_HTTP_ROOT
Root path of http server, defaults to /
HELLO_GRPC_ADDR
Address to bind grpc server, defaults to 0.0.0.0:9106
HELLO_ASSET_PATH
Path to custom assets, empty default value

Health

HELLO_DEBUG_ADDR
Address to debug endpoint, defaults to 0.0.0.0:9109

Commandline flags

If you prefer to configure the service with commandline flags you can see the available variables below.

Global

–config-file
Path to config file, empty default value
–log-level
Set logging level, defaults to info
–log-color
Enable colored logging, defaults to true
–log-pretty
Enable pretty logging, defaults to true

Server

–tracing-enabled
Enable sending traces, defaults to false
–tracing-type
Tracing backend type, defaults to jaeger
–tracing-endpoint
Endpoint for the agent, empty default value
–tracing-collector
Endpoint for the collector, empty default value
–tracing-service
Service name for tracing, defaults to hello
–debug-addr
Address to bind debug server, defaults to 0.0.0.0:9109
–debug-token
Token to grant metrics access, empty default value
–debug-pprof
Enable pprof debugging, defaults to false
–debug-zpages
Enable zpages debugging, defaults to false
–http-addr
Address to bind http server, defaults to 0.0.0.0:9105
–http-root
Root path of http server, defaults to /
–grpc-addr
Address to bind grpc server, defaults to 0.0.0.0:9106
–asset-path
Path to custom assets, empty default value

Health

–debug-addr
Address to debug endpoint, defaults to 0.0.0.0:9109

Configuration file

So far we support the file formats JSON and YAML, if you want to get a full example configuration just take a look at our repository, there you can always see the latest configuration format. These example configurations include all available options and the default values. The configuration file will be automatically loaded if it’s placed at /etc/ocis/hello.yml, ${HOME}/.ocis/hello.yml or $(pwd)/config/hello.yml.

Usage

The program provides a few sub-commands on execution. The available configuration methods have already been mentioned above. Generally you can always see a formated help output if you execute the binary via ocis-hello --help.

Server

The server command is used to start the http and debug server on two addresses within a single process. The http server is serving the general webservice while the debug server is used for health check, readiness check and to server the metrics mentioned below. For further help please execute:

ocis-hello server --help

Health

The health command is used to execute a health check, if the exit code equals zero the service should be up and running, if the exist code is greater than zero the service is not in a healthy state. Generally this command is used within our Docker containers, it could also be used within Kubernetes.

ocis-hello health --help

Metrics

This service provides some Prometheus metrics through the debug endpoint, you can optionally secure the metrics endpoint by some random token, which got to be configured through one of the flag --debug-token or the environment variable HELLO_DEBUG_TOKEN mentioned above. By default the metrics endpoint is bound to http://0.0.0.0:9109/metrics.

go_gc_duration_seconds
A summary of the GC invocation durations
go_gc_duration_seconds_sum
A summary of the GC invocation durations
go_gc_duration_seconds_count
A summary of the GC invocation durations
go_goroutines
Number of goroutines that currently exist
go_info
Information about the Go environment
go_memstats_alloc_bytes
Number of bytes allocated and still in use
go_memstats_alloc_bytes_total
Total number of bytes allocated, even if freed
go_memstats_buck_hash_sys_bytes
Number of bytes used by the profiling bucket hash table
go_memstats_frees_total
Total number of frees
go_memstats_gc_cpu_fraction
The fraction of this program’s available CPU time used by the GC since the program started
go_memstats_gc_sys_bytes
Number of bytes used for garbage collection system metadata
go_memstats_heap_alloc_bytes
Number of heap bytes allocated and still in use
go_memstats_heap_idle_bytes
Number of heap bytes waiting to be used
go_memstats_heap_inuse_bytes
Number of heap bytes that are in use
go_memstats_heap_objects
Number of allocated objects
go_memstats_heap_released_bytes
Number of heap bytes released to OS
go_memstats_heap_sys_bytes
Number of heap bytes obtained from system
go_memstats_last_gc_time_seconds
Number of seconds since 1970 of last garbage collection
go_memstats_lookups_total
Total number of pointer lookups
go_memstats_mallocs_total
Total number of mallocs
go_memstats_mcache_inuse_bytes
Number of bytes in use by mcache structures
go_memstats_mcache_sys_bytes
Number of bytes used for mcache structures obtained from system
go_memstats_mspan_inuse_bytes
Number of bytes in use by mspan structures
go_memstats_mspan_sys_bytes
Number of bytes used for mspan structures obtained from system
go_memstats_next_gc_bytes
Number of heap bytes when next garbage collection will take place
go_memstats_other_sys_bytes
Number of bytes used for other system allocations
go_memstats_stack_inuse_bytes
Number of bytes in use by the stack allocator
go_memstats_stack_sys_bytes
Number of bytes obtained from system for stack allocator
go_memstats_sys_bytes
Number of bytes obtained from system
go_threads
Number of OS threads created
promhttp_metric_handler_requests_in_flight
Current number of scrapes being served
promhttp_metric_handler_requests_total
Total number of scrapes by HTTP status code