Introduce version command and handler

[pavolloffay]

No description provided.

[coveralls]

Coverage remained the same at 100.0% when pulling 61cbf22 on pavolloffay:build-version into 2b73fe9 on jaegertracing:master.

[black-adder]

wow, had no idea this was even possible.

[pavolloffay]

also could somebody with mac run it, I am not sure if date command works there too.

[black-adder]

Running on mac

make build-query-linux
CGO_ENABLED=0 GOOS=linux installsuffix=cgo go build -o ./cmd/query/query-linux -ldflags "-X github.com/uber/jaeger/pkg/version.commitSHA=2b73fe9aa45a54c6cbf3e9459a01a31a7ce6bdcc -X github.com/uber/jaeger/pkg/version.latestVersion=v0.9.0 -X github.com/uber/jaeger/pkg/version.date=2017-11-07T14:34:04Z" ./cmd/query/main.go

[yurishkuro]

how will it work on the command line, since we now have a root command and a single sub-command

[yurishkuro]

otherwise lgtm

[pavolloffay]

./cmd/collector/collector-linux help

Jaeger collector receives traces from Jaeger agents and agent and runs them through
				a processing pipeline.

Usage:
  jaeger-collector [flags]
  jaeger-collector [command]

Available Commands:
  version     Print the version

Flags:
      --cassandra.connections-per-host int           The number of Cassandra connections from a single backend instance (default 2)
      --cassandra.keyspace string                    The Cassandra keyspace for Jaeger data (default "jaeger_v1_local")
      --cassandra.max-retry-attempts int             The number of attempts when reading from Cassandra (default 3)
      --cassandra.password string                    Password for password authentication for Cassandra
      --cassandra.port int                           The port for cassandra
      --cassandra.proto-version int                  The Cassandra protocol version (default 4)
      --cassandra.servers string                     The comma-separated list of Cassandra servers (default "127.0.0.1")
      --cassandra.socket-keep-alive duration         Cassandra's keepalive period to use, enabled if > 0 (default 0s)
      --cassandra.timeout duration                   Timeout used for queries (default 0s)
      --cassandra.username string                    Username for password authentication for Cassandra
      --collector.health-check-http-port int         The http port for the health check service (default 14269)
      --collector.http-port int                      The http port for the collector service (default 14268)
      --collector.num-workers int                    The number of workers pulling items from the queue (default 50)
      --collector.port int                           The tchannel port for the collector service (default 14267)
      --collector.queue-size int                     The queue size of the collector (default 2000)
      --collector.write-cache-ttl duration           The duration to wait before rewriting an existing service or operation name (default 12h0m0s)
      --collector.zipkin.http-port int               The http port for the Zipkin collector service e.g. 9411
      --config-file string                           Configuration file in JSON, TOML, YAML, HCL, or Java properties formats (default none). See spf13/viper for precedence.
      --dependency-storage.data-frequency duration   Frequency of service dependency calculations (default 24h0m0s)
      --es.max-span-age duration                     The maximum lookback for spans in ElasticSearch (default 72h0m0s)
      --es.num-replicas int                          The number of replicas per index in ElasticSearch (default 1)
      --es.num-shards int                            The number of shards per index in ElasticSearch (default 5)
      --es.password string                           The password required by ElasticSearch
      --es.server-urls string                        The comma-separated list of ElasticSearch servers, must be full url i.e. http://localhost:9200 (default "http://127.0.0.1:9200")
      --es.sniffer                                   The sniffer config for ElasticSearch; client uses sniffing process to find all nodes automatically, disable if not required
      --es.username string                           The username required by ElasticSearch
      --log-level string                             Minimal allowed log level (default "info")
      --span-storage.type string                     The type of span storage backend to use, options are currently [cassandra,elasticsearch,memory] (default "cassandra")

Use "jaeger-collector [command] --help" for more information about a command.

./cmd/collector/collector-linux version -h

Print the version and build information

Usage:
  jaeger-collector version [flags]

./cmd/collector/collector-linux version --cassandra.keyspace=foo

Error: unknown flag: --cassandra.keyspace
Usage:
  jaeger-collector version [flags]

{"level":"fatal","ts":1510132598.8778965,"caller":"collector/main.go:146","msg":"unknown flag: --cassandra.keyspace","stacktrace":"main.main\n\t/home/ploffay/projects/golang/src/github.com/uber/jaeger/cmd/collector/main.go:146\nruntime.main\n\t/home/ploffay/bin/go/src/runtime/proc.go:195"}

./cmd/collector/collector-linux version

{"gitCommit":"61cbf2201789915389c3f9acf12f943117aeeb48","GitVersion":"v0.9.0","BuildDate":"2017-11-08T09:14:05Z"}

[coveralls]

Coverage remained the same at 100.0% when pulling 265ddad on pavolloffay:build-version into 2b73fe9 on jaegertracing:master.

[coveralls]

Coverage remained the same at 100.0% when pulling 843aedf on pavolloffay:build-version into 2b73fe9 on jaegertracing:master.